AlanH, back beyond the memory of many bicycling shorts were uniformly black and made of wool jersey fabric. The were cool and comfortable in warm weather. The wool wicks perspiration away from the skin, where it evaporates and cools. Wearing jersey shorts on a hot, low humidity Kansas day was almost like wearing nothing at all. You never felt sweaty. Wool cycling shirts were also available. Given your sewing skills, you ought to be able to whip out some wool jersey shorts in very little time. I've not found wool jersey in any fabric store lately, but have found plenty available online. The fancy lycra cycling clothing doesn't cool like wool. It was adopted by high level racers to reduce drag, and give them a tiny margin of speed that might be critical in a close race. It became fad gear for recreational cyclists, and wool shorts and shirts died out. I used be be a darned serious cyclist and always wore wool, never did like the lycra stuff. I'm kinda getting back into it again, and will be making wool jersey shorts for next summer, it's going to be too cool for shorts soon here.

A reenactor/guide at the Fort Larned historic site, along the Sate Fe Trail in south central Kansas, told me his wool uniform was quite comfortable outdoors, where the evaporative cooling effect could work. Indoors, where he wasn't exposed to the wind, the wool uniform cold become uncomfortable in the un-air conditioned buildings.