Topic: How accurate is a 5n1

[DoctorKnow]

Doctor Know.... How did you ensure that the holes didn't crack? So you took a screw larger than the small holes and made them larger?

George/Harold... If you don't want exact accuracy, why even have a station? I want to know what the temp is at my house with the greatest accuracy possible. If I just cared that it was too hot for golf or lawn work, I'd just use the Accuweather app or watch my local news.

You don't need "exact accuracy" to have useful data.  +/- 1F is usually good enough for most purposes. 

It's impossible to have "exact accuracy", anyway.  The best you can do is keep chipping away at the uncertainties involved.

I wouldn't bother with enlarging the holes.  You could probably remove the entire grill and not see a verifiable difference. 

We just want to enjoy our hobby. Hopefully, all this isn't too upsetting. ROFL

[nincehelser]

Doctor Know.... How did you ensure that the holes didn't crack? So you took a screw larger than the small holes and made them larger?

George/Harold... If you don't want exact accuracy, why even have a station? I want to know what the temp is at my house with the greatest accuracy possible. If I just cared that it was too hot for golf or lawn work, I'd just use the Accuweather app or watch my local news.

You don't need "exact accuracy" to have useful data.  +/- 1F is usually good enough for most purposes. 

It's impossible to have "exact accuracy", anyway.  The best you can do is keep chipping away at the uncertainties involved.

I wouldn't bother with enlarging the holes.  You could probably remove the entire grill and not see a verifiable difference. 

We just want to enjoy our hobby. Hopefully, all this isn't too upsetting. ROFL

I suspect in a few weeks you'll be back complaining that your readings are off and then come back with another magic fix.  It's a repeating pattern...

[Inverno]

Ironically, the station just west of you was 2 degrees cooler today. I checked the other day and it was around 2 degrees cooler too. It's an Ambient station too. Looks like you may be experiencing what I am.

[DoctorKnow]

Ironically, the station just west of you was 2 degrees cooler today. I checked the other day and it was around 2 degrees cooler too. It's an Ambient station too. Looks like you may be experiencing what I am.

Both my tower in the sun shield and my 5 in 1 hit 94. The 5 in 1 used to be at least 3 degrees more, and I really think they are right now because I have compared with a mercury instrument. If acurite is 2 F off on every sensor, then we are screwed.

Here is the nearest Davis, a few blocks the other side of me from the Ambient. It also hit 92. I don't think every part of town would be 92 exactly. http://www.weatherlink.com/user/riverstjaxnc

[Inverno]

I have multiple Davis stations near me. They all read 76 as a high, the three Acurite stations read 78 as a high.


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[haroldashe]

"George/Harold... If you don't want exact accuracy, why even have a station? I want to know what the temp is at my house with the greatest accuracy possible. If I just cared that it was too hot for golf or lawn work, I'd just use the Accuweather app or watch my local news."

I have many things more worthy of my concern than a 1 deg. difference between a $80 sensor suite and a $12 tower.  If I was that worried about it, I would probably buy a much more expensive set-up.  And, for what it's worth, a sensor suite, like the 5in1, is a compromise at best.  For example, unless yours is 33' (10 meters) above level ground with no obstructions anywhere near it, your wind speed data will be somewhat incorrect when compared to airport readings.  If it is 33' high, temps will be compromised, etc.  It's just the nature of the beast.

[Inverno]

Harold, I think you're missing my point. Yes we all have more impotent things than our weather station. I do want accuracy but unfortunately I cannot afford to go buy a $1000 weather station. When I do buy a $150 station, I expect the temperature to be as, if not more accurate than a $2 mercury thermometer. Is that too much to ask from Acurite? If you aren't interested in accuracy, then why not just watch the news or look online for the interpolated readings in your town? 88, 90, 93 degrees, it's hot right?

[DoctorKnow]

Everyone's lows all around were 72 last night, including mine. So if someone can figure out what gives us the extra 2 degrees in the daytime, it will be an amazing feat. Acurite specs say 2 degree error, so technically, there is no problem... other than we are real serious about accuracy.

[nincehelser]

Harold, I think you're missing my point. Yes we all have more impotent things than our weather station. I do want accuracy but unfortunately I cannot afford to go buy a $1000 weather station. When I do buy a $150 station, I expect the temperature to be as, if not more accurate than a $2 mercury thermometer. Is that too much to ask from Acurite? If you aren't interested in accuracy, then why not just watch the news or look online for the interpolated readings in your town? 88, 90, 93 degrees, it's hot right?

If those are your expectations, you will be sorely disappointed with some Davis and Ambient systems that don't come with fan aspiration and can run a degree or two F higher than might be expected.

[Jáchym]

Harold, I think you're missing my point. Yes we all have more impotent things than our weather station. I do want accuracy but unfortunately I cannot afford to go buy a $1000 weather station. When I do buy a $150 station, I expect the temperature to be as, if not more accurate than a $2 mercury thermometer. Is that too much to ask from Acurite? If you aren't interested in accuracy, then why not just watch the news or look online for the interpolated readings in your town? 88, 90, 93 degrees, it's hot right?

If those are your expectations, you will be sorely disappointed with some Davis and Ambient systems that don't come with fan aspiration and can run a degree or two F higher than might be expected.

If it was just a degree or two it would still be quite good .... it can get much worse

[Inverno]

Funny you say that George, the Davis systems near me that are 2 degrees cooler are passive systems.


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[DoctorKnow]

So I moved the solar shield to the huge Oak trunk and now my readings are spot on temp and humid wise with the two airports, and is 3 degrees less than the 5 in 1 and the Ambient, and is 1 degree less than the Davis. This isn't the way to site, but whatever works... Trial and error with these things. I will watch it over a time and adjust the exact spot to minimize error.

[nincehelser]

Funny you say that George, the Davis systems near me that are 2 degrees cooler are passive systems.

So you'd be OK spending around $500 (Amazon) VP2 without aspiration realizing it can be a few degrees F off what should be expected?

What happened to your concerns about "exact accuracy"?

[Inverno]

If you read my previous post, I wrote that expensive stations are not in my budget.  Maybe $150 is chump change to you but to me, it's expensive enough that my temperature should be very, very close... Not high continuously.


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[nincehelser]

If you read my previous post, I wrote that expensive stations are not in my budget.  Maybe $150 is chump change to you but to me, it's expensive enough that my temperature should be very, very close... Not high continuously.

You're missing the point.  That non-aspirated Davis system is not always going to be "very, very close" to the actual temperature.  In some cases it might be high continuously throughout the day during daylight hours.

For some reason you're willing to let a $500 Davis system off-the-hook for your "exact accuracy" expectations, yet you are demanding a $150 Acurite to be held to a higher standard?

This is a good example of why comparing readings to neighboring systems is a dicey proposition.  There are many variables involved and you can't be sure how "exact" the neighboring systems are.  You need to confirm the temperature at your particular location in a controlled fashion.  That eliminates many of the problem variables, including siting.

You've already put up a second device in your location and found a 1.5F degree difference.  That's not unreasonable given the uncertainties involved with both devices.  If you want to narrow it down further, you need to look into calibration against a reliable source and work from there.

[Inverno]

I've discussed this for years on here so yes I understand all the basics about the variables involved.

The issue here is that other Davis and Ambient passive systems are reading lower by about 1.9-2.3 degrees lower than my active Acurite system, along with the other Acurite systems in the area. It's not a coincidence, there is a slight "problem" with Acurite's system. I'm not the first person to point this out with examples. I like Acurite products, just want a little better accuracy.


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[nincehelser]

I've discussed this for years on here so yes I understand all the basics about the variables involved.

The issue here is that other Davis and Ambient passive systems are reading lower by about 1.9-2.3 degrees lower than my active Acurite system, along with the other Acurite systems in the area. It's not a coincidence, there is a slight "problem" with Acurite's system. I'm not the first person to point this out with examples. I like Acurite products, just want a little better accuracy.

I'm sure you do.  I'm just suggesting a way to eliminate all the unknown variables for those of us aren't in a privileged position to see.

I don't agree with your concepts on "accuracy", though.  Perhaps I should just go listen to the radio.   

[Inverno]

No George, you are the type of person that keeps Acurite in business, you settle for 2 degrees off.


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[nincehelser]

No George, you are the type of person that keeps Acurite in business, you settle for 2 degrees off.

We're done here.  Good day, sir.





 

[DoctorKnow]

With all the authoritarians pumping climate change by rising thermometers, we can't afford 1 degree. Even an amateur scientist should see that as a valid argument.

[nincehelser]

With all the authoritarians pumping climate change by rising thermometers, we can't afford 1 degree. Even an amateur scientist should see that as a valid argument.

It sure would be nice if all weather stations could report with such accuracy, but that's not the current reality.  Even official government stations have to contend with things like concrete being built up around them throwing things off.

Scientists try to account for error and station distribution issues with statistical methods. 

They also rely heavily on satellite data... it gives more surface coverage, plus the temperature of the lower 10km of the atmosphere.

Even a fake doctor should know this basic info.

[DoctorKnow]

Inverno,

I managed to get the right high temp with the tower sensor in the tree where it doesn't come in contact with direct sun on the shield. I am now the same as the Davis and Ambient, as well as the nearest NWS site. The sensor tends to read low though all during the day until the sun gets on the shield just enough to meet the actual high. I guess I'll leave the shield on the tree trunk... The 5 in 1 does read about 3 degrees high for me.

[Inverno]

I've been building a new tower sensor shield that I should have done tonight. Those cheap bowls crack after the cold winter. My old installation spot got a bit of sun but I'll find a new spot in the shade.

I've been still reading 1.8 to 3 degrees higher than the Davis near me. There is another Acurite a stone's throw from the Davis reading the same as me. Either we are high, or the Davis is low.


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[DoctorKnow]

I think we are high. The radiation shield must be perfect, and I believe Davis has it down.

[CW2274]

The radiation shield must be perfect, and I believe Davis has it down.

Not perfect, but the VP2 shield with a proper fan, especially where I live, is very tough to beat.