Is there a reliable backpackign thermometer out there?

Cheap thermometers are good

Main problem is they can be off by a few degrees. Fill a bowl with ice cubes, fill with water. Put thermometer in the middle and stir. Wait a few minutes. Remember difference between thermometer reading and actual freezing temp. I always just write the freezing temperature on the thermometer, like "34" if the thermometer reads 2 degrees high.

I use a small digital version made for restaurant/food prep work and has a high/low memory function. You can find them in any upscale cooking store, or better yet, a restaurant supply store. Ranges vary, so buy to suit. Typical food range is -40f to 450f, so that will cover most hiking conditions ;) You will find a bunch on eBay too. Taylor is a decent brand. Go for a waterproof one while you're at it.

Most of these little thermometers have an auto shutoff, so they won't keep sampling, as in recording an overnight low. You can find some small indoor/outdoor models (Radio Shack and others) than can do that. Accuracy is not lab grade by any means and they are the size and weight of a pocket radio.

I have the Accurite Thermometer and it works really well. I don’t know how accurate it is, but it keeps track of the 24-hour high and low for you as well (based upon when you put the battery in).

It’s less than $6 and my local Wal-Mart carried it. It’s only 1.2 ounces (including the battery, but without the suction cup). I kept the little battery strip and simply wrap it around the battery after each trip to save the battery.

Someone broke apart the plastic shell and cut the weight almost in half if you want to go that far…

I have an old, old, old zipper pull combo thermometer and button compass from REI. It's so scratched up I can barely read it, but the temps have always been pretty accurate. They still sell those.

I've got the same one as Kevin. Its great for recording the overnight low but its been less useful during the day. If I stick it in the outside pocket of my pack and it happens to be in the sun for a while the temp sky rockets. A few weeks ago it reported that it was over 90* when it was only around 65*. Not knowing the real day time temperature isn't a huge loss but it would be nice to know for my trip journal. It's so light and cheap that I'm going to work with it and see if I can find somewhere the store it that gives more accurate day time temps.

Adam

It's not the thermometer's fault, it's your placement. If it's in an outside pack pocket, it'll warm up from sun. And you want it away from body heat.

If you dangle thermometer from outside and wait for a time that your pack is out of the sun for a while it can be fairly accurate.

Plus, some thermometers have thermal mass that can take an hour to stabilize. Little cheap zipper pull thermometers aren't too bad.

I realized at the time it was the placement that was skewing the reading, I'm just not sure of the best place to put it. I'm going to try it in the hipbelt pocket next time, my hope is that it will be insulated from my body and not in direct sunlight. If that doesn't work I might put it in the top layer of the body of the pack. Then my concern is it being too insulated. I think I'm putting way too much thought into this $6 thermometer!

Adam

Remember day time temps as reported by weather stations are measured in the shade (a small amount of effort is taken to eliminate heat by solar radiation). The temperature differential can easily be +30F going from shade to sun and more if you have dark clothing on.

I'd find it all interesting if I didn't live in a region that routinely sees 100-115F in the shade for a solid 3 months of the year.

My REI keychain thermometer has been decent so far, but i don't expect it to last indefinitely or be reliable in sub freezing temps.s

If you put it on hipbelt it will be effected by body temp. Inside pack will be way off.

Weather stations have like a reflective roof to provide shade, lots of air flow on all sides, doesn't seem practical for backpack.

And if you're in a shady spot under a tree it will be cooler than if you're in a sunny place, even if you have a shady roof over it.

Better to have it outside pack. Wait until you're at a shady spot. Low thermal mass thermometer so it quickly stabilizes.

I also have the same one as Kevin.

http://www.walmart.com/ip/Accurite-Thermometer-with-Suction-Cup/16888909

I removed the suction cup, and the plastic shell. Weighs 17 grams and records 24hr Highs and lows as stated above.

I only have it to assess my sleep setup based on trip lows.

+1 on Rob & Kevin, except I haven't removed the shell yet. The max function is useless for daytime temps. The min function is quite useful for assessing sleep system performance under varying conditions. A slight breeze makes a bigger difference than 4-6° F!

I keep an REI zipper-compass on my packs for daytime temps. Redundant now, but I've had them on packs and PFDs for decades. I should find a way to hang the Acurite from my pack, but keep it protected from rain.

Calibrated – only to my comfort levels, and the comfort of those around me.

As a trip leader who can be quite comfy in 50° F windy conditions wearing shorts and a t-shirt, I want an objective temperature to remind me to look after others who start shivering at 71° F. Plus or minus a few degrees F doesn't matter that much for those purposes. I can't even read the zipper compasses that close!

— Rex

I'm surprised nobody has mentioned the Garmin Tempe which integrates with many of their GPSs. I use mine with an eTrex 30 which provides the readout. The Tempe pod weighs 10 grams (1/3 oz) and attaches to whatever you want – overnight I attach it to a guy line. It provides a max and min reading for the previous 24 hours and current temperature.

it works really well. I don't know how accurate it is,

Somehow the above comment made me smile…

A slight breeze makes a bigger difference than 4-6° F!
Not sure how to read that because that AcuRite Thermometer does not appear to be able to account for wind chill.

A wind chill chart :

(BTW I take wind chill charts with a grain of salt but that is OK because I'll sweat it out anyway)

http://www.tiptemp.com/Products/Thermometers/COCSEN017

I can usually assess the temperature close enough by feel and experience, within a couple degrees. Thats in humid SE conditions, sheltered from wind, and inactive.

Put me out west where its dry , start moving and heating up, and Id be way off. Howver the only thing Im ever interested in was the overnight low, and that, Im pretty good at.

SUN has several small thermometers. Although graduated in 5F increments, the ones I have have proven fairly accurate (used on my kids science project, and compared with a better thermometer).

I bought four of the Accurites that Kevin mentioned. I hung them all in a shaded place with no wind. A few days later the current, min and max temps were all within 1 degree of each other.

Good enough for me.

If you just want to know the temperature at one point in time a zipper pull thermometer like the REI one mentioned above work well and there are a lot of companies making them.

If you want the minimum and maximum temperatures for the entire day the acurite is a good choice but again there are a lot of companies making such devices. Some companies make them with a USB connector and memory so you can download the data from every day of your trip into your computer. Some also include humidity sensors. I haven't used any of these USB devices. In another forum the I button was mentioned.

If you want more such as wind chill you might want to look at something like the Kestrel 3500. I purchased one for a project and figured I might occasionally bring it on a hike. Well after I got it and stripped it down (removed the lanyard, cord stop and hard shell case) I found it weighed 2oz (55g). Thats about 1/2oz less than my altimeter watch.

the Kestrel 3500 measures wind speed, temperature, humidity, pressure and has a clock. The temperature sensor has a fast response and one takes a second or two to give an accurate reading. With wind speed and temperature it calculates wind chill. The temperature and humidity sensors are used to calculate the dew point and the pressure sensor also calculates altitude. So I don't need to bring my watch anymore.

The only limitations are that the clock doesn't keep track of date or have an alarm function. It automatically turns off after 45 minutes so collecting a days worth of data is not possible,and there no way to downloaded the data. Kestrel does sell units capable of recording data long term but they weigh and cost more.

Sorry about the comment regarding the accuracy…When I reread it I had to smile as well. I really like that it captures the low temperature because I use that info to evaluate my sleep system.

In terms of how weather-resistant it is, my parents have one affixed to the outside of a window on their RV. They leave it outside regardless of the weather and haven't had any problems with it. They take it off when they're traveling, but other than that it's always on the window.

I clipped mine to a carabiner that I attach to my pack. I simply remove the "battery strip" around lunchtime the first day of my trip and know that it will reset the 24-hour that time each day. Works really well.

I wonder is this might be useful:

I've ordered one of those themodos. When I eventually get it I'll comment on it's accuracy and usability.

So  how did the Thermodo work out? I’m very interested in the idea.

I just use a zip-pull thermometer, but when I buy one, I look at the dozen display and pick the one with the most accurate reading at the store temperature, or if I can’t discern that, the one with the median temperature.

Haven’t used the Thermodo, but I see a few issues for lightweight backpackers.

Your phone needs to be on and running to record temperatures. If you want to record the overnight low, expect to have a nearly dead phone by morning, since most phones my phone can’t run continuously for 8+ hours, and cold temperatures also reduce battery output. You could carry an external battery pack – which weighs at least an order of magnitude more than the Thermodo. Plus a charging cable.

Thermodo temperature readings can be pushed higher by the heat from the phone. The app has a (constant) fudge factor, but my phone’s temperature varies widely depending on use. To help with the problem, Thermodo sells a short extension cable. Oh joy, one more cable. And how much does that weigh?

Thermodo uses this mythical thing called a “headphone jack.” If you don’t have one built into your iAndroidPhone XXII, then you’ll need some kind of adapter dongle. One more tiny thingy to lose in the backcountry, one more tiny thingy adding grams to your back. And oops – can’t charge the phone and use most headphone adapters, too. Guess you won’t get that overnight low after all.

And the app reviews are … mixed.

There are plenty of lighter, simpler, … better alternatives. I’m still happy with my keychain thermometer for everyday use, and Accurite when I want overnight lows.

— Rex

After trying a variety of logging devices with very mixed success I’ve found that Blue Maestro makes a product that addresses my curiosity and doesn’t drain my phone or wallet much.  I’m using the Tempo Disc Bluetooth Wireless Thermometer, Hygrometer, Barometric Pressure meter, found on Amazon.  They make a variety of devices, some only available directly from Blue Maestro, some on Amazon.  Some measure just temperature, others temperature and humidity, others add barometric pressure.  Some can be immersed in water, some need to be protected from rain.

The devices are about the size of a quarter, and have a wide variety of configuration settings.  They record data internally at a user set frequency, and transmit it to the phone when requested.  There is no need to have continuous phone contact or communication.  My device collects 6000 data points for each parameter internally before overwriting the oldest points.  You can easily download the data, and the control app displays tables and graphs of the data which can also be saved as a csv. file for viewing later off line.  My device measures from -40 to +85 C, with a .4 C accuracy.  If you want, you can buy devices with a calibration curve provided.  On my scale the tempo is about 0.2 ounces.  Since I usually have my phone on at airplane mode when hiking, I can place the disc in a protected location, out of direct radiation in my pack and see the current statistics just by looking at the phone.  The coin battery is rated at 1 year continuous use.  You can even control the strength of the Bluetooth signal, which can markedly extend battery life.  At max strength, the signal is supposed to reach 275 feet.  I’ve tested it at better than 90 feet with no problem.  Since ordinarily the sensor will be within a few feet of me, I’ve decreased the transmission power markedly.  I’ve read negative things about prior versions of the app, but I find the current version quite easy to use and intuitive.

Renais