Topic: Comparing Acu-Rite 01015 to NWS Standard Rain Gauge

[wxtech]

I just had a heavy rain 3:35pm - 3:55pm 110820.  I measured the accumulation in the National Weather Service standard rain gauge and compared it to the Acu-Rite 01015 and to the Davis VP2+ with a Waterlog H-340 tipping bucket gauge.
NWS SRG =0.35"
Acu-Rite = 0.35"
Davis VP2 = 0.33"
CoCoRaHS = 0.35" (4" plastic pro gauge)
I will make a correction on the Davis VP2 because that feeds the web site and the station annual totals.
http://www.lexingtonwx.com/

[Rhino]

Results look good! We are finding some folks are having rain inaccuracies, but after some investigation we found that it was mostly due to mounting- if the unit moves in the wind too much it will register rain due to the measuring bucket being tipped.

By the way, just curious-did you need to calibrate the 01010 rain gauge at all?

[jeeptj5]

We had a rain event here in the Chicago area today and my (1050c) display unit logged .45 inch of rain.  My web site reading was .34 inch of rain for the same period.  The connection to the server was good the whole time and the signal strength to the bridge and the display unit is full bars.  Any thoughts on the discrepancy???

[Rhino]

I have seen discrepencies like this from 2 identical rain gauges placed mere feet apart many many times, i would say in general it is well within the (real world) margin of errors for most rain gauges. You could run some tests and calibrate the 5n1 rain. Gauge though...

[George Richardson]

Rhino,
What jeeptj5 stated amounted to a 33% error which I seriously doubt would be "
well within the (real world) margin of errors for most rain gauges.".

George

[wxtech]

With the Acu-Link web bridge, sometimes the data indicated on the display doesn't match what is on the backyard weather site or what Wunderground shows.  It appears that Jeeptj5 is using just the one rain sensor.

[DanS]

With the Acu-Link web bridge, sometimes the data indicated on the display doesn't match what is on the backyard weather site or what Wunderground shows.  It appears that Jeeptj5 is using just the one rain sensor.

It kind of sounds like the "rackspace server outage at Acu-rite HQ" issue you explained happened before with your testing.  http://www.wxforum.net/index.php?topic=13154.msg128104#msg128104 

[jeeptj5]

What I was referring to was the difference between my one 5-in-one sensor's display on the hardware display unit and the data reported on my "backyard weather" page.  I noticed that as the storm progressed the difference widened.

[Rhino]

Ahhhh, understood. This was an issue we had with the older firmware. If you log into the bridge from your browser-what firmware do you have?

[tonyguy2000]

I have the same problem. The webpage rain total is always lower then what shows on the table top display. I called tech support today and Jenny told me it's an ongoing problem due to conversion from metric mm to inches. I don't know what she meant so I changed unit to mm and it rained again today and the web portal still showed less than my display. I called tech support again and this time I was told it's because Acurite's server has problems rounding up numbers. Could some please tell me what is going to be the fix. Thanks.

[Weather Display]

how much is the difference?
does the difference get larger the more rain there is?
(i.e could be a scaling/conversion factor)

[tonyguy2000]

For example, yesterday we had a 3 hour heavy downpour. The display read 3.25 inches while the web portal read 2.7. And yes, the more rain the bigger the difference percentage wise.

[wxtech]

These last few posts are confusing because they aren't comparing rain gauges, the original topic.  These last posts above are people complaining that Acu-Rite has modified their data prior to displaying their data on "My Backyard Weather" and sending their data to WeatherUnderground.
 
I say again that the Acu-Rite 5-n-1 compares favorably with the NWS SRG.  Comparing rain gauges on my last rain event:
NWS SRG =0.47"
Acu-Rite 5-n-1 = 0.47"
Davis VP2 = 0.43"  corrected to 0.47"
CoCoRaHS = 0.48" (4" plastic pro gauge)
Peet Ultra Pro = 0.494"
Suton/Fischer-Porter weighing rain gauge = 0.4x"?
R M Young 50202 failed on siphon due to low, misting rain rate
 

[tonyguy2000]

Sorry, I will repost again in it's own thread.

[txagwx]

I just had a heavy rain 3:35pm - 3:55pm 110820.  I measured the accumulation in the National Weather Service standard rain gauge and compared it to the Acu-Rite 01015 and to the Davis VP2+ with a Waterlog H-340 tipping bucket gauge.
NWS SRG =0.35"
Acu-Rite = 0.35"
Davis VP2 = 0.33"
CoCoRaHS = 0.35" (4" plastic pro gauge)
I will make a correction on the Davis VP2 because that feeds the web site and the station annual totals.
http://www.lexingtonwx.com/

I have the Davis Vantage Vue and the Acurite.  Both are roughly the same temperature, although I think the Acurite reads about 1F warmer.  There are some days when the Acurite will read warmer than the Vue in full sun...but it is usually within 1-2F.  Not a bad weather station for the price.  Rainfall totals have been about the same between the Vue and the Acurite, although my NWS plastic 11" gauge reads less than both of them.  All 3 stations are within 15 feet.