Keeping stick-on thermometers dry

On my last batch, I used a stick-on thermometer to monitor the fermentation temperature of my glass carboy in a swamp chiller. The thermometer was above the water line, but the wet t-shirt eventually soaked it. Does anyone have a good system for covering/sealing stick-on thermometers so they don't get wet?

Covering it with some clear packing tape does the trick. Go past it enough to seal it off from the water.

i used a stick on thermometer for my first batch about 2 years ago. it's still on the side of my fermenter but it's such crap at this point that i don't trust it or use it. i can't even read it anymore anyway. i spent $8 on a good solid glass brewing thermometer that i can sterilize in boiling water and stick and leave in the fermenting beer or wort at any time. i'd just go to the local hardware store or hb shop and pick one of those up when you can so you don't have to worry about a stick on thermometer.