Perugia enjoys a traditional Mediterranean climate – cold winters and hot, dry summers. It can get very hot during the day in the summer, but somewhat chilly at night given Perugia’s high altitude.
The likely best time to visit Perugia is from the spring (roughly March or April) to the early fall, like October. This is, of course, the most stable time of year to visit, weather-wise, and yet it will also be the most busy. If you want to avoid crowds and perhaps get some off-season deals on hotels and airfare, consider travel during the winter months.
During the peak summer months of June and July, highs average around 78 degrees in Perugia, though it can get quite a bit hotter. But since Perugia is at a high altitude, it cools down considerably at night, so pack accordingly.
If you happen to visit Perugia in the winter months, bundle up. Highs in December average in the mid-40s, and lows dip into the low and mid-30s. Perhaps the best time to visit Perugia is in April, before the crowds descend and when the weather is warmer than winter (average highs in April are in the mid-50s), but not warm enough to bring in the big tourist crowds.