Topic: WeatherFlow

[stromb0li]

Hey WXForum,

It's been awhile since I was looking at the weather station market, but noticed a "new" one called WeatherFlow, which appears to have started from a crowd sourcing venture and has recently become more commercially manufactured:
https://weatherflow.com/smart-home-weather-stations/

Per their stats:

Measurement	Range	Accuracy	Interval
Air Sensor
Air Temperature	-35°F to 140°F	± 0.7°F	1 min
Relative Humidity	0 to 100%	± 4%	1 min
Atmospheric Pressure	up to 1100 mbar	± 1 mbar ; station and sea-level	1 min
Lightning activity	0 to 40 km (25 miles)	upto 40% of strikes at 5km	Instantly
Wireless	100m (300ft++)	sub-Ghz telemetry
Sky Sensor
Wind Speed	0 to 100 mph	± 0.5 mph	continuous sampling
Wind Direction	0-359°	± 5°	continuous sampling
Ambient Light	1 to 128 kLUX	± 100 mLUX	1 min
UV Index	0 to 11+ index		1 min
Solar Irradiance	0 to 1900 W/m2	± 5%	1 min
Rain Intensity	Light to Torrential	± 0.2mm / hr	Instantly
Rain Accumulation	1hr and 24hr	± 20%	1 min
Wireless	100m (300ft++)	sub-Ghz telemetry

Many of the stats appear to contend close to what my Vantage Pro2 has, except for UV Index range and Air Temperature range... but in doing a quick search on the forums it appears reviews of this have been all over the board.  With the device offering to be solar powered and no moving parts, it's compelling to look at this as an alternative.

Curious what your thoughts are!

[CW2274]

Two deal breakers for me. One, the "air" must be shaded at all times (virtually impossible for myself), or you'll need some kind of radiation shield, which is another problem in itself.
Two, the rain fall accuracy is abysmal.
Personally, not worth the price of admission.

[dport]

Appears to be complete junk from what I have seen in watching a couple local WeatherFlow units on WU.  As mentioned above, if a ray of sunlight hits the "air" the temp spikes rapidly (i.e. if it's truly 85 F, I've seen these units spike to 95 F).  This means you need to place it up against a house, shed, etc and try to grab as much shade as possible.  These structures in themselves will create erroneous readings (let alone the fact that true temp is measured in the sun).

[havtrail]

Hey WXForum,

It's been awhile since I was looking at the weather station market, but noticed a "new" one called WeatherFlow, which appears to have started from a crowd sourcing venture and has recently become more commercially manufactured:
https://weatherflow.com/smart-home-weather-stations/

<snipped>

Many of the stats appear to contend close to what my Vantage Pro2 has, except for UV Index range and Air Temperature range... but in doing a quick search on the forums it appears reviews of this have been all over the board.  With the device offering to be solar powered and no moving parts, it's compelling to look at this as an alternative.

Curious what your thoughts are!

If you use this forum's search function, it will help you:
https://www.wxforum.net/index.php?topic=35368.0

Rich K.

[waiukuweather]

the AIR sensor needs to be placed in a proper instrument shelter for sure

[nincehelser]

AIR does have to be kept out of the sun or put in some sort of shield.

I've not had much luck with the AIR's lightning detection feature.  Compared to my other AS3935-based sensors, it seems "deaf".

The SKY eats batteries quickly, and requires 8 lithiums.  I've just installed the new solar panel which replaces the batteries completely.  It's 40% off until May 31st.

The rainfall readings on my SKY haven't been very accurate due to vibrations.  There's a new mounting available which is said to isolate it better, but I don't have that yet.

Lack of a display kind of bugs me, but you can make your own with an inexpensive tablet.

I like the way they broadcast data on your local network.  That way you don't need a direct connection to get your data.

[txweather.org]

So to sum what nince said. It has issues

[nincehelser]

Not the word I would use.

Someone has to pioneer, and that means taking a few arrows.

[txweather.org]

Not the word I would use.

Someone has to pioneer, and that means taking a few arrows.

Indeed.

[vreihen]

With the exception of rainfall measurements, my WeatherFlow Sky tracks very nicely against my Davis VP2 on the same mast under most conditions.



I have the Air mounted to the north wall of my detached/unheated garage in permanent shade, and it actually performs better than the VP2 with the passive radiation shield on sunny days.

The open local access to data via UDP broadcast is a lesson that every other PWS vendor should learn from WeatherFlow, and rumor has it that some geek wrote a pretty solid WeeWX driver to gather them up and send the observations everywhere.....

[weather34]

AIR does have to be kept out of the sun or put in some sort of shield.

I've not had much luck with the AIR's lightning detection feature.  Compared to my other AS3935-based sensors, it seems "deaf".

The SKY eats batteries quickly, and requires 8 lithiums.  I've just installed the new solar panel which replaces the batteries completely.  It's 40% off until May 31st.

The rainfall readings on my SKY haven't been very accurate due to vibrations.  There's a new mounting available which is said to isolate it better, but I don't have that yet.

Lack of a display kind of bugs me, but you can make your own with an inexpensive tablet.

I like the way they broadcast data on your local network.  That way you don't need a direct connection to get your data.

nincehelser the air use for lightning its not too bad see below from this morning but it needs positioning and requires a lot of trial and error to find that sweet spot.however big trade off is being vulnerable to high unreal temperatures .mine is horizontally mounted and not used for temperature I use a second Air mounted in a home made shield.

Rainfall its improved in terms of sensitivity and under the hood remote adjustments to calibration but the big but is anyone living in an area susceptible to frequent high (i do all year round) winds of 50kmh or more is going to get false rain especially under very frequent gusty periods in minutely intervals.we went through a rare quiet period when i first installed this 2019 package but last week the winds returned and the rainfall measurements went all wonky as it wasn't even raining.

The recent package from March 2019 received, the addition of the solar panel is a big bonus , the superhydrophobic coating treatment to reduce the wind drop outs or erratic wind direction readings during long periods of rainfall works very well .the new cushioned pole mount helps reduce building/pole vibrations but as above overall rain area the design struggles to cope with the shear brute wind force when hitting the rain sensor area . think about it if you ever the get opportunity go and stand outside in the strong wind especially gusty winds of 50kmh or more put your hand up in the air you will feel the wind force.the results get worse as the wind gusts increase in speed .
so even with out being mounted on a pole a common thought about pole vibrations being the only issue its not , Ive done many tests on short poles /long pole and no poles ! when ive had the opportunity and simply come to the conclusion wind force is major factor of false rain due to the nature of technology and the design..

yes the lack of console is a big thing always was my first thought from the early days ,the latest weatherflow App software release for IOS has just rendered my iPad Mini useless which i used solely as a console unfortunately my original iPad minis not possible to upgrade the IOS OS itself beyond IOS 9.6 so I no longer have a permanent device to mount and view without buying an additional solution.
so the approach that everyone has a smart device to hand for use needs a rethink .there are third party solutions available but most are not stable and requires some ongoing upkeep.

so some pictures as they always speak louder than words
this morning Air mounted horizontally



false rain no actual rain that day




have a good day all..brian

[pfletch101]

With the exception of rainfall measurements, my WeatherFlow Sky tracks very nicely against my Davis VP2 on the same mast under most conditions.

I have the Air mounted to the north wall of my detached/unheated garage in permanent shade, and it actually performs better than the VP2 with the passive radiation shield on sunny days.

How do you know which is 'better'? Do you have a 'gold standard' system on your site?

[vreihen]

How do you know which is 'better'? Do you have a 'gold standard' system on your site?

The curse of owning more than one measuring instrument is never knowing which one is correct.  As the owner of eight rain gauges of various types, I could be easily convinced that *none* of them are correct!

No 'gold standard' system here, but I do have a custom weewx report that overlays both VP2 and WF data on the same daily graphs where you can see the two lines diverging every morning shortly after sunrise on clear days...with the VP2 in the sun with a passive shield reading 1-2 degrees F warmer than the WF in the constant shade on the north wall of the detached/unheated garage.

FWIW, the Davis VP2 is my station of record reporting to CWOP et al.....

[pfletch101]

How do you know which is 'better'? Do you have a 'gold standard' system on your site?

The curse of owning more than one measuring instrument is never knowing which one is correct.  As the owner of eight rain gauges of various types, I could be easily convinced that *none* of them are correct!

No 'gold standard' system here, but I do have a custom weewx report that overlays both VP2 and WF data on the same daily graphs where you can see the two lines diverging every morning shortly after sunrise on clear days...with the VP2 in the sun with a passive shield reading 1-2 degrees F warmer than the WF in the constant shade on the north wall of the detached/unheated garage.

FWIW, the Davis VP2 is my station of record reporting to CWOP et al.....

If I wanted to be a pain (perish the thought!  ), I would repeat my question, pointing out that, given that the most authoritative meteorological temperature readings are taken by carefully calibrated thermometers in well ventilated enclosures in the sun, the shade temperature measured by the AIR is at least as likely to be erroneously low (compared to such a measurement) as the VP2's reading is to be high. With any reasonable amount of air movement (since you have a passive shield) my money would be on the VP2's reading as closer to 'reality'.

[vreihen]

Here's the Davis VP2 (blue line) and WF (red line) temperature graph from today.  Notice how the WF is reading warmer than the VP2 just before sunrise, and then the VP2 reads warmer during daylight hours:



Throwing some data science at the VP2's readings, here's the MADIS prediction (red line) versus actual VP2 readings (blue line) for today's CWOP/APRS readings:



The VP2 is reading lower than the MADIS prediction during the night, and higher during the day.

The VP2 is reading lower than the WF Air just before sunrise, and higher than the WF during the day.

The VP2 is passing MADIS QC for temperature.  While I don't have a WF-vs-MADIS graph, I am reasonably certain that they track each other closer than the VP2 does.

FWIW, the VP2 is a 13 month-old aerocone setup with the SHT31, and the WF Air being recorded is also 13 months old.....

[CW2274]

Your side by is certainly a true comparison (sensors being equal, which is another thing in itself). Using MADIS to determine which is possibly more accurate overall...forget it. It may be right, but just as likely it's not. The only way you'll truly know (apples to apples) is to stick the VP2 in constant shade also, because you certainly can't do that to the "air".

[pfletch101]

Here's the Davis VP2 (blue line) and WF (red line) temperature graph from today.  Notice how the WF is reading warmer than the VP2 just before sunrise, and then the VP2 reads warmer during daylight hours:

Throwing some data science at the VP2's readings, here's the MADIS prediction (red line) versus actual VP2 readings (blue line) for today's CWOP/APRS readings:

The VP2 is reading lower than the MADIS prediction during the night, and higher during the day.

The VP2 is reading lower than the WF Air just before sunrise, and higher than the WF during the day.

The VP2 is passing MADIS QC for temperature.  While I don't have a WF-vs-MADIS graph, I am reasonably certain that they track each other closer than the VP2 does.

FWIW, the VP2 is a 13 month-old aerocone setup with the SHT31, and the WF Air being recorded is also 13 months old.....

While your direct comparisons are not proof of your contention, I agree that they are (at least) suggestive, particularly if today was not unusually calm (which would, of course, disfavor the VP2). I am impressed by how well the two devices track at night, which suggests that there isn't a fixed offset between them. I also have to ask what the weather was like in the first early evening shown on the comparison graph, where they also track very well - much better than at the same time on the following day. Was it quite windy or overcast?

[vreihen]

It rained up until midnight the night before.  There were passing dark clouds in the afternoon on the graphs, and 20+ MPH wind gusts at mast level.

The more interesting comparison is using Weewx's daily averages to compare anemometers.  On a typical day, the vector average speeds are usually identical, and the vector average direction are exactly three degrees apart.  It is very possible that my aging eyeballs mis-calibrated the north marks on the two anemometers by 3 degrees when mounting them together on the shared mast.

Being ultrasonic, the WF Sky does record extremely low winds (think drafts) that aren't strong enough to spin the cups on a mechanical anemometer.  It also seems to record slightly higher quick-hitting peak gusts at times, possibly due to the momentum lag with accelerating the cups.  As I said, they come out pretty close looking at daily averages.  Water in the wind sensor path is an issue with wind accuracy for some owners, and WF is supposedly using some sort of surface treatment to mitigate this on the current shipping Sky hardware.

It bears mentioning that WeatherFlow is not a startup company.  They operate a large commercial network of near-shore automated weather stations (using commercial equipment), and employ data scientists and meteorologists to produce several specialized commercial forecast products.....

[weather34]

unfortunately rain measurements  is a big issue .

this morning intense flash flood like conditions 20 minute burst then another 10 minute burst .
overall rain period aprox 1 hour

VP2 7.2 mm or 0.28in 30 minute period
Weatherflow same period 3.2 mm or 0.126in stopped  registering rainfall during really intense bursts did not restart measuring rainfall until i guess the surface of the rain sensor area dried or build up drained off . i actually thought the unit had failed but the wind readings continued
reporting .

the surface treatment has eradicated previous issue of wind sensor failure or erratic wind direction readings under these intense conditions.throughout the downburst wind readings functioned ,in the past i.e last year wind readings either stopped or went erratic .

overall the rain measurements under intense conditions is a big issue , as an enthusiast this is where you want some relative valid figure .however under steady or light rain conditions it does well . as we now head into the storm season of flash flood like conditions where an hour later you would hardly known it had rained with such intensity and i dont have much hope of being able to use it reliable . if they can nail this one big issue because i dont live in an extreme weather location but susceptible too adverse conditions and and frequent winds .

on the back of this mornings intense we had our first land tornado appear though short and nothing significant as seen in the USA the tornado area was some 3-5km away . but just an indication of localized conditions .

below shows the period where it stopped recording though it was raining very very hard
 [ You are not allowed to view attachments ]

[Dennis Rogers]

Traditional rain buckets are not always reliable, break down and need regular maintenance and often stop works and not always give accurate rainfall either

[weather34]

Traditional rain buckets are not always reliable, break down and need regular maintenance and often stop works and not always give accurate rainfall either

thats true and perhaps its good to know weatherflow are considering adding a tipping bucket , make no mistake they have had a lot of problems with rainfall and they are no closer to resolving it with the haptic ...piezo sensor method and on the back of that any one outside of usa is not able to use there latest method of calibration, you will see when it arrives and not only that if you own existing hardware well you’ll   spend more time comparing than actually using them for what is was designed for or intended unless thats your interest... sadly im not convinced and not see anything to tell me or convince otherwise.. hence there toying with the idea of tipping bucket.. i no longer use mine the uv has gone awol in less than 6 months of use and donated 3 other complete packages to locals and students . ps how you calculate vibrations into a true accumulation of rainfall is beyond me , i always thought piezo type sensors were good for transferring vibrations or pressure they make good cheap acoustic guitar pickups..

positive side of tipping bucket designs you have some chance to remedy the discrepancies or fault using a piezo sensor doesnt offer much chance.. sorry to be negative but 2 years of testing there are still some issues to resolve..brian

[Dennis Rogers]

True a sensor for rainfall could never work, but the plus side if far more accurate wind speed.

I did read its 10x more sensitive at picking up wind over cups which has some weight to push and drag even before it detects wind.

Think the way it measures wind is the strong point and even detects draughts which cups wont pick up.

The whole practical no maintenance and wind are its main selling point.

But with a rain bucket some stations you can calibrate them.

I think the most accurate system would be the use of like a manual rain gauge with no tipping bucket, so like a manual rain gauge fills up with rain and at midnight then empties it.

But would need a sensor to show how much rain is collected.

Maybe weight or sensors in the gauge itself. Or floating sensor measuring height of rain then midnight reset but emptying it.

Think there has to be a better way than bucket tipping as you wont get accurate results either unless you are given the option to calibrate it and many stations you cannot. And will still never be quite accurate.

And as many have their stations to high up the rain gauge is out anyway.

Seems many place wind over rain measurements anyway. Which is 5 in 1s are often high above the roof.

For rain no good there. But wind is great and where the weather flow shines.

[waiukuweather]

you can get a second wind/rain sensor and place that at ground level and then use that for the rain reading

[CW2274]

Traditional rain buckets are not always reliable, break down and need regular maintenance and often stop works and not always give accurate rainfall either

thats true and perhaps its good to know weatherflow are considering adding a tipping bucket , make no mistake they have had a lot of problems with rainfall and they are no closer to resolving it with the haptic ...

Obviously the "big boys" concur. Here's the just the intro, the full article is the link should anyone want.

https://www.weather.gov/media/asos/ASOS%20Implementation/awpagimplan.pdf

11.INTRODUCTION1.1 Description of Technology Improvement Scheduled For ImplementationThe Automated Surface Observing System (ASOS) is equipped with a Heated Tipping Bucket RainGauge (HTBRG) for the measurement of precipitation.   The HTBRG accurately measures liquidprecipitation in most rain events except for excessively heavy rain events where the tipping bucketcannot tip fast enough and keep up.  For freezing or frozen precipitation (e.g.,  freezing rain, snow, etc.)the HTBRG uses  a heated collar and funnel to melt snow and ice so they can be collected by  thefunnel and measured by the tipping bucket.   However, the heated funnel sometimes excessively meltssnow resulting in significant evaporation/sublimation/convection losses and consequent under reportingof liquid equivalent precipitation accumulation.  At other times, the heating is insufficient to preventsnow from building up, bridging over the gauge orifice, and forming a cap which prevents any furtherprecipitation from falling into the gauge and being measured.  This results in under reporting ofprecipitation accumulation during the precipitation event, and a false surge report when the cap melts ata later time.  For this reason, NWS ASOS Planned Product Improvement (PPI) Program has identifiedan alternate technology precipitation gauge to replace the HTBRG at National Weather Service (NWS)-sponsored ASOS sites.  The ASOS All Weather Precipitation Accumulation Gauge (AWPAG) ismanufactured by Ott Hydrometrie of Germany and is designed to provide accurate measurement of alltypes of precipitation.   In contrast to earlier weighing gauge designs, the AWPAG does not use oil(environmentally unfriendly) to prevent evaporation.  The AWPAG measures precipitation by weighingtotal accumulation and uses environmentally friendly antifreeze to liquefy the collected snow.  TheAWPAG also compensates for evaporation and wind-induced vibration effects via the internalalgorithm.The AWPAG can only be installed at sites equipped with the ASOS PPI processor upgrade.  Theprocessor upgrade  incorporates numerous approved software enhancements and provides the increasedprocessing capability needed to support the ASOS PPI components:o   replacement dew point sensor (the DTS1),o   ice free wind sensor (the Model 425),o   AWPAG,o   enhanced precipitation identifier, ando   ceilometer replacementThe AWPAG contract is with C. C. Lynch and Associates of Pass Christian, Mississippi, representingOtt Hydrometrie of Germany, the gauge manufacturer.  The AWPAG measures precipitation byweighing its total accumulation using strain gauge technology to convert the weight to an electricalsignal.  The AWPAG resolution is 0.01 inches and the gauge capacity is 40 inches of liquid equivalentprecipitation.  There is additional capacity to hold approximately 13 inches of antifreeze whichliquefies the snow collected, reducing its volume while not changing its weight.  The AWPAG includesa metal windshield to minimize aerodynamic collection losses of snow and the orifice rim is heated inlow temperatures to prevent snow and ice from building up on the rim and reducing the diameter of the orifice.

[weather34]

True a sensor for rainfall could never work, but the plus side if far more accurate wind speed.

I did read its 10x more sensitive at picking up wind over cups which has some weight to push and drag even before it detects wind.

Think the way it measures wind is the strong point and even detects draughts which cups wont pick up.

The whole practical no maintenance and wind are its main selling point.

my own experience of comparing cups(vp2) is the weatherflow begins to fall behind has the wind increases , calm winds are rare events here so the lower end is never noticeable but the frequent lower  5-10 kmh reading of the weatherflow is noticeable  i.e yesterday wf 35kmh max vp2 41kmh sometimes its greater sometimes a marginal difference but its far more consistent in wind than it is measuring rainfall.. we are only 10 minutes into a new day so last 10 minutes wf max 15kmh vp2 22.7kmh both are aprox 80ft agl clear view..150 metres from sea front..as i said before you end up spending too much time comparing so i dont monitor both simultaneously i just take a look when the conversations arise .. if they take the path of releasing an additional separate rain module and a specific well designed radiation shield,address some of the quality control  then i think they have a real good chance accomplishing a well made innovative weather station for the home enthusiast but dont buy into its a challenger to the trusted davis vp2 range and alike .

vp2 range with its flexibility, the upgrade path,the replaceable parts are very beneficial , you say low maintenance is a strong selling point however i tend to not quite see it that way the downside of low maintenance means pretty much no replaceable parts simply have to replace whole unit or buy another ...

the sky unit needs a clear 360 view with no nearby objects,buildings in its path the reflected winds can send the directions erratically off considerably .

cw2274 im in harmony with that ...