Most electronic controls have an upper temperature range of about 150ºF±, so be careful if the outer box is in direct sunlight and it's a dark color. It can pretty hot in those things. If you could sit it in the shade or under a deck, etc. that would help.
If you're unsure how hot it gets, I'd suggest getting a thermometer and putting in there and checking it during the hottest part of the day a few times to see how hot it gets.
I looked through the manual and didn't see an upper operating temp for the control box, so you may want to call Maytronics to see what they say.