have not owned garmin dash cam in hot weather-yet. would advise not to use a micro sd card larger than 32g as mine would not function well with a 64g card. works fine with a 32g card though with no problems just be certain its a high speed card as garmin advises. also i would try to locate as high on the windshield as possible, behind the tint strip if your windshield has this feature, just don't get tint strip in image, takes a little effort. very satisfied with my purchase so far.