Temperature and humidity play a major role in the handling of the cars. I would argue that humidity plays a larger role than temperature. AC lowers temperature, but also humidity quite a bit when in operation.

at a home track, a cheap weather station with humidity and temp can help see what the favorable conditions are at your track.

last RCCW race, there was a bad thunderstorm going through, and a lot of the cars lost their setup around that time. Humidity shot up through the roof. The same happened at the PN NAC and it got really messy during the 2nd round of mains. As humidity rises, it tends to make the cars more edgy in my experience. Some tires react to it more noticeably.