Author Topic: Humidity wont go over 97%  (Read 5929 times)

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Offline Bashy

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Humidity wont go over 97%
« on: June 28, 2017, 01:03:18 AM »
Hi folks,

Its been hammering down now for 18hrs straight, if i measured the rain from 8am til 8am then it would be
60mm and loads to go yet, so, how come the humidity wont go over 97% and it took hours to get there from 96%
I have a Vue down the road at 100% so Davis does go to 100% i have 2 RAF US occupied bases at 100%, oh
hold on, Marham RAF base (official UKMO Station) is only at 95%, should i shut up now?
Kind regards
Bashy

Offline CW2274

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Re: Humidity wont go over 97%
« Reply #1 on: June 28, 2017, 02:24:29 AM »
Rain does not 100% humidity necessarily make. Thick fog is about the only safe bet. That being said, with your others reading 100%, even professional sensors can have difficulty pulling the 100% trigger whereas others not as much. Common issue.

Offline Bashy

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Re: Humidity wont go over 97%
« Reply #2 on: June 28, 2017, 02:30:32 AM »
Cheers, we did have thick fog towards the end of winter and still the same then, so it looks like mine is 97 tops
Kind regards
Bashy

Offline CW2274

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Re: Humidity wont go over 97%
« Reply #3 on: June 28, 2017, 03:25:40 AM »
Cheers, we did have thick fog towards the end of winter and still the same then, so it looks like mine is 97 tops
If you're using this as it appears on your site, Oregon Scientific WMR928NX, then 98% is as high as your sensor will register just as is.

Offline Bashy

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Re: Humidity wont go over 97%
« Reply #4 on: June 28, 2017, 03:27:29 AM »
Thats the old station still in use mind but not servicing the site, thats the Davis VP2, my sites info has not been updated as yet..
« Last Edit: June 28, 2017, 04:05:26 AM by Bashy »
Kind regards
Bashy

Offline belfryboy

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Re: Humidity wont go over 97%
« Reply #5 on: June 28, 2017, 04:34:33 AM »
If your sensor is the SHT11 then @ 100% the tolerance is +/- 5%, if it's the SHT15 then you get a slightly better +/- 4%. If it's the SHT31 then the best you can hope for is +/- 2%. So all in all I'd say your sensor is within tolerance, for an electronic sensor.

Offline Bashy

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Re: Humidity wont go over 97%
« Reply #6 on: June 28, 2017, 04:51:31 AM »
Thanks, not got a clue whats in it, i got it in February this year
« Last Edit: June 28, 2017, 11:25:01 AM by Bashy »
Kind regards
Bashy

Offline Lucht

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Re: Humidity wont go over 97%
« Reply #7 on: June 28, 2017, 03:31:25 PM »
I have the same problem with my Vantage Vue. The ISS which has just been upgraded to the latest electronics package and yet still won't go above 97% even in fog.

Offline CW2274

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Re: Humidity wont go over 97%
« Reply #8 on: June 28, 2017, 03:52:39 PM »
I have the same problem with my Vantage Vue. The ISS which has just been upgraded to the latest electronics package and yet still won't go above 97% even in fog.
The Vue only comes with the SHT11, so even more problematic hitting 100%, but can happen.

Offline Lucht

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Re: Humidity wont go over 97%
« Reply #9 on: June 28, 2017, 03:54:40 PM »
Thanks for that. At least I now know why  :-)

Offline Billyram

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Re: Humidity wont go over 97%
« Reply #10 on: June 28, 2017, 05:10:06 PM »
The most I've seen with my VP-2 is 98% but I see it regular this time of year.
Billy

Offline LeeWx

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Re: Humidity wont go over 97%
« Reply #11 on: June 28, 2017, 05:20:24 PM »
My Vue did great up until a very wet period last summer(about 5 years use). It registered 100% many times when socked in with fog. Since that period last summer it only reaches about 76% now and then drops as humidity rises to as low as 36% in heavy fog.

Offline Jáchym

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Re: Humidity wont go over 97%
« Reply #12 on: June 28, 2017, 05:26:06 PM »
I get 99% almost everytime it rains, is humid, foggy etc., but 100% Ive only seen a few times.

Offline CW2274

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Re: Humidity wont go over 97%
« Reply #13 on: June 28, 2017, 05:59:45 PM »
My Vue did great up until a very wet period last summer(about 5 years use). It registered 100% many times when socked in with fog. Since that period last summer it only reaches about 76% now and then drops as humidity rises to as low as 36% in heavy fog.
Sensors wear out like everything else. Time for a new one.

Offline PaulMy

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Re: Humidity wont go over 97%
« Reply #14 on: June 28, 2017, 06:54:19 PM »
I just checked my maximums and since installing in November 2008 my VP2 has had:
2008 no 100% humidity
2009 5 months had 1 day at 100% and 1 month had 2 days
2010 4 months had 1 day at 100%
2011 2 months had 1 day at 100%, 2 months had 4 days, 2 months had 5 days, and December had 11 days
2012 1 month had 1 day at 100%
2013 no days at 100%
2014 1 month had 1 day at 100%
2015 1 month had 1 day at 100%
2016 2 months had 1 day at 100%
2017 1 month with 1 day at 100%

All other days had highs from 89% to 99%
Not sure why 2011 had 31 days at 100%.

Paul

Offline dendrite

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Re: Humidity wont go over 97%
« Reply #15 on: June 29, 2017, 08:05:12 AM »
I just checked my maximums and since installing in November 2008 my VP2 has had:
2008 no 100% humidity
2009 5 months had 1 day at 100% and 1 month had 2 days
2010 4 months had 1 day at 100%
2011 2 months had 1 day at 100%, 2 months had 4 days, 2 months had 5 days, and December had 11 days
2012 1 month had 1 day at 100%
2013 no days at 100%
2014 1 month had 1 day at 100%
2015 1 month had 1 day at 100%
2016 2 months had 1 day at 100%
2017 1 month with 1 day at 100%

All other days had highs from 89% to 99%
Not sure why 2011 had 31 days at 100%.

Paul
That's all with the same sensor?


I've hit 100% a few times with my SHT31, but usually it maxes around 96-98% during the warm season. In the winter it maxes around 92-95%. The 98-100% tend to occur with a prolonged saturated stretch with higher dewpoints (60F+).

Offline PaulMy

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Re: Humidity wont go over 97%
« Reply #16 on: June 29, 2017, 11:18:21 AM »

Yes all with the original - I haven't touched it in any way other than clean out the rain gauge occasionally and changed the battery once about 6 years ago.


Maybe time to get a replacement (WS station that is - like the guy who got a new car when the ash tray was full ;) )


Enjoy,
Paul

Offline dalecoy

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Re: Humidity wont go over 97%
« Reply #17 on: June 29, 2017, 11:27:39 AM »
Cheers, we did have thick fog towards the end of winter and still the same then, so it looks like mine is 97 tops

If that is causing you great pain and discomfort, isn't that exactly what the console calibration is for?

Offline ct

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Re: Humidity wont go over 97%
« Reply #18 on: June 29, 2017, 04:57:27 PM »
Right now my SHT31 is at 100%, SHT35 is at 99.7%.  Both sensors in same FARS.

Offline CW2274

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Re: Humidity wont go over 97%
« Reply #19 on: June 29, 2017, 05:19:43 PM »
Right now my SHT31 is at 100%, SHT35 is at 99.7%.  Both sensors in same FARS.
OK, sorry OT, I know you're an electronic whiz, how tough is it to get a 35 to work with our VP2's?
« Last Edit: June 29, 2017, 05:55:25 PM by CW2274 »

Offline Lucht

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Re: Humidity wont go over 97%
« Reply #20 on: June 29, 2017, 05:54:44 PM »
I get 99% almost everytime it rains, is humid, foggy etc., but 100% Ive only seen a few times.

Got fog here right now. The Vue is saying 96%.

Offline ocala

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Re: Humidity wont go over 97%
« Reply #21 on: June 29, 2017, 06:29:48 PM »
My Vue did great up until a very wet period last summer(about 5 years use). It registered 100% many times when socked in with fog. Since that period last summer it only reaches about 76% now and then drops as humidity rises to as low as 36% in heavy fog.
You might want to pull out that sensor and see if it needs a cleaning. Bugs and-other critters can block the ports that might affect the readings.
The blues had a baby and they named it Rock & Roll

Offline CW2274

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Re: Humidity wont go over 97%
« Reply #22 on: June 29, 2017, 07:04:46 PM »
Right now my SHT31 is at 100%, SHT35 is at 99.7%.  Both sensors in same FARS.
OK, sorry OT, I know you're an electronic whiz, how tough is it to get a 35 to work with our VP2's?
And by the way, how are you reading humidity resolution to a tenth of a percentage?

Offline ct

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Re: Humidity wont go over 97%
« Reply #23 on: June 29, 2017, 07:28:16 PM »
how tough is it to get a 35 to work with our VP2's?

I'm using I2C type SHT31/35 sensors with my own controller.  The VP2 uses a different type of interface (SMBus?) which won't work with these I2C sensors.

Offline dalecoy

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Re: Humidity wont go over 97%
« Reply #24 on: June 29, 2017, 07:39:32 PM »
Right now my SHT31 is at 100%, SHT35 is at 99.7%.  Both sensors in same FARS.

Which one is correct?

 

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