What kind of jersey for summer heat and sun?
This is a matter of personal preference. I live in a hot climate. I've worn everything from sleeveless jerseys with perforated backs to long-sleeved jerseys in hot weather. My current preference is for long-sleeved jerseys, in order to get the added sun protection. There aren't a lot of lightweight long-sleeved jerseys, but there are some, and some advertise their SPF ratings.
Some clothing manufacturers advertise &quot;coldblack&quot; jerseys (black, but intended for hot weather). I've never tried one, and I'll admit I'm skeptical they'd be comfortable. I always wear lighter colors.
Jerseys are designed to wick sweat and breathe well. Modern performance textiles are pretty amazing.