You ride your bike with mittens??At 94 deg F like last week and no rain, I wear cotton BLACK work gloves from Dollar Tree. These allow me to twist the shifter without slipping on my sweat, and keep my hands from being sunburned. I can't shift in the rain with the twist shifter in bare hands, but it prevents the white castle slider sized cyst over my thumb the shimano index shifter caused. My hands were roasted red in 2016 when I was using a shimano index shifter & no gloves: right through the SPF 60 sun screen.
At 6 deg F with a 30 mph wind as in January, I wear Wells Lamont mittens from the Rural King Farm supply. All synthetic, I believe. You have to pay extra for deer skin, which I don't see the point of with all the petroleum based alternatives that insulate better.
I wear long sleeved cotton red hat workshirt and long leg Dickies polyester cotton pants, in all weather. Wicks off the sweat, prevents sunburn, prevents road rash if I hit my forearms or knees. Some woman at a bus stop shouted today "how can you stand to wear all that?". I learned in marching band in texas, your never as hot was when you are sunburned. Cotton wicks up the sweat and cools you. Dark colors block UV better than light colors. It was very nice today, sunny, 90 degree, 10 mph headwind which slowed me down but made me very comfortable. Knocked off 20 oz water and 20 oz cold diet soda (7-up) on my 30 mile trip today.