Topic: Recommendations for a PWS for extreme cold location

[toofarout]

Well Darn!  There I was, getting all excited over nothing.   
Thank you johnd.

[sleepypup]

I live in the heart of the Canadian Prairies (Regina, SK) and cold temperatures extremes are likely very close to what you experience.  Like you, winters are long and -20 to -30 F is a regular occurrance in winter and -30s not uncommmon.  In January 2004 I recorded my all time low at -40.8 C on my first generation VP. That was a cabled version but I have since replace that with a wireless VP2 and have no complaints with the ISS battery life.  Ran 2 winters with the same battery.  I know others that automatically replace the battery every fall to ensure trouble free data transmissions all winter.   

So it would appear that the VP can record values below -40.  I assume there is some buffer built into the specs claim.  On the day I recorded the -40.8 C the local airport metar recorded -41.8 C which is about the difference I would expect as I live in a suburban area.

Hope this helps and keep warm.  Regina is currently sitting at a balmy -15 F...-38 with the windchill. 
Dean  http://nwrweather.com/

[PaulMy]

So it would appear that the VP can record values below -40.  I assume there is some buffer built into the specs claim.  On the day I recorded the -40.8 C the local airport metar recorded -41.8 C which is about the difference I would expect as I live in a suburban area.

Not at my location but I had followed a Davis station in Baffin Island a couple winters ago on WU and several times it flat lined at -40 or slightly lower but not -41.0.  The nearest airport recorded somewhat lower.

Paul

[sleepypup]

The temp as you see in the image did cross the -40 threshold a couple of times.  Again,  Davis specs claim -40 but some units may squeeze out a little more range.   Thankfully the coldest I have seen since that record day is -36.2 C.    Details aside, I would not hesitate to subject the Davis products to extreme cold based on what I have observed over the past 12 years.

[toofarout]

The temp as you see in the image did cross the -40 threshold a couple of times.  Again,  Davis specs claim -40 but some units may squeeze out a little more range.   Thankfully the coldest I have seen since that record day is -36.2 C.    Details aside, I would not hesitate to subject the Davis products to extreme cold based on what I have observed over the past 12 years.

Thanks Dean,
Every winter I see cold spells lower than -40F, -45F is commonplace, and every few years there is a cold spell of -55F or lower.  The lowest I've known I've encountered was below -60F, the thermometer bottomed out at -60F so I'm not sure how much lower it was.
Anyway, If the Davis pws went to at least -50F I probably wouldn't hesitate to get one.  Right now I am still trying to figure something out.  They seem to be good and uncomplicated.  I did hear back from a Davis sales rep through email, he said their temperature sensors will not read lower than -40.  I think that means it won't register -41, since yours obviously registered -40.8C. 
Seriously, the way I look at temperature here, anything *above* -40F (-40C) is OK, though I'd prefer temps from -15F to 15F above!

Lonnie at Rainwise emailed and said all their pws read as low as -67F, but the batteries and the electronics cannot be guanenteed below -40.  I've asked him about moving the battery and electronics box away from the temp./humidity sensors and using a low wattage battery warmer pad and switching out the battery at intervals during the winter, and perhaps wiring in a larger solar panel, haven't heard back yet of course since it is the weekend.

I not only live in a cold sink valley, but the ridge to the south blocks all available possible sunlight for 2 months each winter.  It gets light out, but sun is below the ridge.  I don't know enough about solar to know if a wireless pws could run all winter on that little sun.  Maybe I should move.   Hawaii always looks real good to me about this time of year. 

A cabled pws might work better than wireless?????  I am electronically deficient so not sure about how I could handle something that complicated. 
Gee, it was all so much easier when I worked at the weather stations in the military, all the putting things together stuff was done by someone else!

[sleepypup]

I see that you are in a particularly challenging location and I must concede that you are colder than southern Saskatchewan.  We typically just have to deal with added wind with trees few and far between.

I think the battery would get you through 1 winter if you replaced it each year in November but agreed a cabled unit might make the most sense in your situation.  I get a couple of hours of sun a day on mine in winter and that has been enough to pull the battery through 2 winters already.  Either way if you are looking to record those extreme temps the Davis will fall short it would appear.

Good luck and I look forward to an update on this post when you come up with solution.