Thermometer?

[Justin Baker]

I’m looking for a thermometer that is reliable, accurate, and can record the night time lows while I sleep. I’m trying to do personal research on clothing and sleep systems. Can anyone recommend me something? I don’t mind spending a little extra for something good.

[Bob Moulder]

I don’t have one, but I’ve been researching this myself lately and saved the link for This One.

Just wondering what happens to the battery at -50°C…(?)

edit to add: it is switchable to Farenheit scale

[d k]

Hi, Justin –  I got this one a while back and it works well for me (as long as it’s not directly exposed to a clear night sky, which apparently will cause a thermometer to read falsely low).

P.S.  Found it at Home Depot, I think – either there or Orchard Supply Hardware.

here

 

 

[Rex Sanders]

d k’s Acurite and other thermometers are featured in “Backpacking With A Thermometer“, with 48 replies. Might be useful.

— Rex

[Dean F.]

Kestrel makes several weather and environmental meters, though I have never used one.  Their premium one measures:

• Altitude
• Barometric Pressure
• Density Altitude
• Dew Point
• Heat Stress Index
• Relative Humidity
• Temperature
• Wet Bulb Temperature (Psychrometric)
• Wind Chill
• Wind Speed

[Jay L]

I have the Acurite too (picked mine up at Wally World).  It works well for what it is.  One thing to note is that it resets high/low every 24hrs.  You have to pick when you want them to reset, wait for that time then pull the battery for a moment to reset the device.

I also have the Elitech RC5 temperature logger.  It is a USB device that logs temperature data over time.  I wanted to log the temps over my entire trip and pull them off to the computer when I got home so I could generate graphs etc.  It works pretty well – you use the software to set how often it takes a reading and the same software to pull data off.  It shows the current temperature on the little display but does not show the high/low on the display.  My only complaint is that every time I pull it out of the gear bin (about once a month) I have to replace the battery.

 

[David Thomas]

99 cents, free shipping, 22 grams, remote bulb.  No high/low recording, though:

http://www.ebay.com/itm/LCD-Refrigerator-Freezer-Fridge-Digital-Thermometer-Temperature-50-110-ac-T5-/181925439966?hash=item2a5b99e9de:g:jIoAAOSwT5tWPg3y

“(as long as it’s not directly exposed to a clear night sky, which apparently will cause a thermometer to read falsely low).”

Yes and no.  If you are trying to read air temperature, then, yes, you want to shield the thermometer or its probe from having a direct view of the night sky – everything radiants heat away from itself and if all the objects around are close to air temperature, then you’ll get an accurate air temperature reading.  But if exposed to a  clear night sky, especially with no wind, and especially at high elevation, then objects (thermometers, people, tents, sleeping bags) radiant away more heat than they receive from deep space (which is at about 4K absolute).  This is why you can have frost on your lawn or car when the air temperature was well above freezing.

If you’re recording temperatures to learn about your sleeping system’s limits, I’d suggest you look at both air temperature (put a leaf over the probe, or use the “indoor” reading with the unit in the tent) and also at air temperature less the radiant effects by putting the remote sensor outside with a view of the night sky.  You’ll learn more about total heat loss and how siting your shelter under a tent can make a huge difference.

[Kenneth Keating]

I use a Traceable Products Min/Max #4145 thermometer.  I can read and record  min/max readings for both indoor and outdoor temps while I’m in my tent, so that makes it nice.  I velcro it to my shoulder strap while hiking so I can easily get to it while on the move.  Size is 4-1/4 x 1 x 5/8 inches. Cable length is 3′ and the probe is submersible which also allows me to take water temps.

 

[Jerry Adams]

99 cents???  How can they do that?  Shipping must be more than that

I was experimenting with measuring temperature under clear night sky.  Tried experiment with wrapping sensor in foil to minimize radiant heat loss.  And shielded under a cover that blocked night sky.  And a sensor exposed to the night sky.

Didn’t make any difference for a probe sensor.  I figure the probe is exposed to the air on all sides, so it gets the same temperature as air, even though it’s radiating heat to the night sky.

For a meter with enclosed temperature sensor maybe it makes a difference?  It’s bigger.  It would be easy enough to check if you had two temperature sensors – first put both of them under cover and see what the difference is, then put one of them out under the night sky…

Measuring the effect of radiant heat loss is a little trickier.  You could measure with one of those IR remote surface temperature readers.

Your body will be maybe 10 F colder at sea level under a clear sky because of radiant heat loss.

But the ground next to you will also get colder, maybe 20 F after a few hours.  I’ve slept under trees where it was 40 F but 20 F in a nearby meadow.  Sleeping in a tent in a meadow would be somewhat better than just cowboy camping, but the air inside the tent will get close to the outside air temperature and the outside of the tent would get colder because of radiant heat loss.

And it would be much worse if you were exposed to space where it’s close to absolute zero,  Most IR is absorbed in a few thousand feet of air above you, so it’s the temperature of the first few thousand feet of air that’s important.  That’s a few 10s of degrees F colder.

(I know, engineers are unsufferable : )

[Jerry Adams]

and, if it’s 40 F under the trees and you cowboy camp in the meadow at 20 F, you’ll lose an additional 10 F to radiant heat loss – it would be like sleeping at 10 F under trees

and to answer the original question, I have a Brunton ADC Pro – $180 or something – 3 ounces.  Also measures wind speed.  One complaint I have is it takes about 15 minutes for temperature to stabilize – the sensor is buried inside it so the entire instrument has to cool down.  And it has no min/max funtion.

Normally, it’s coldest when you get up in the morning, so you don’t really need the minimum temperature function.  Plus, your metabolism gradually slows over the night, so just before you get up is the most important.

[Rob Reynolds]

I use the Accurite and have no issues.  Works great and I haven’t changed the battery in 2 years.  Pull the suction cup off and you have a nice place to clip on a biner or a loop of cord.

[William Kerber]

I picked this up one over a year ago and haven’t remembered to pack it once. It’s about the size of a flattened cigar and has a clip on the back.

http://www.amazon.com/gp/product/B005Y0RFKO?psc=1&redirect=true&ref_=oh_aui_search_detailpage

 

 

 

[Justin Baker]

I decided to order the accurite, it had decent reviews. I will see how it works. Thanks!

[d k]

I think you’ll like it.  I agree with taking off the suction cup, and the other nice thing is that you can open up the battery “drawer” when you’re not using it, so that it isn’t running down the battery.

[Alex H]

I have 4 or 5 of the Accurites, they all read within a degree of each other and have worked well placed all around our farm.  They don’t take knocks on the head well.  I had one get blown off a hook and it the deck, it was never the same.  I carry one backpacking, seems to read accurately out in the open, hung on something.  They only go down to -5 degrees if that is an issue.

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