ORIGINAL: mewzella
I agree with Aussie....
From the JR FAQ section
What's the maximum and minimum operating temperature of my JR equipment?
0 Degrees Celsius or 32 Degrees Farenheit Minimum
50 Degrees Celsius or 122 Degrees Farenheit Maximum
Funny, I just tried to find anything about this in the manual for my brand new JR radio.... can't find a think about temperature range for the transmitter or the receiver.....
Maybe the assumption is no one would ever fly if the water in your bottle is frozen solid or evaporating due to heat...