Mailing film

Hope this it the right place to ask this.
I mail my film in and was wondering if putting it in a rural type mail box in 100 degree heat will hurt it?
I try to catch the mail carrier when he comes and hand it to him. But sometimes I don't see him.

I have to imagine that the inside of a mailbox will get as hot as the inside of a car in that heat. Whether or not it will damage the film is hard to know for sure without trying it, but it's a risk I wouldn't want to take.

I read about this in a book years ago - the author specifically recommended taking the film to a post office, then carrying it inside rather than leaving it in any mail box that's outside. Once it's out of your hands it's, well, out of your hands but most likely the hottest it would get would be sitting all day long outside waiting to be collected.

That is what I thought. Thanks :)