Among other models, Professional Equipment has a "water resistant" pocket sized model (5" temp. probe) for $19.95. -58 to +300 deg. in .1 deg increments. Great company to do business with. You'll get a monthly catalog from them forever. Just like Edmunds Scientific that Trish mentioned, PE also has a lot of nifty gadgets you'll wish you had more money to buy....
Best of luck from someone else fumbling through how to get one of these contraptions built...
http://www.professionalequipment.com
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Diamondhead