Just an FYI from the Raspberry Pi FAQ:
What is the usable temperature range?
The Raspberry Pi is built from commercial chips which are qualified to different temperature ranges; the LAN9512 is specified by the manufacturers being qualified from 0°C to 70°C, while the AP is qualified from -40°C to 85°C. You may well find that the board will work outside those temperatures, but we’re not qualifying the board itself to these extremes.
70°C = 158°F
85°C = 185°F
Dan