In spring and fall we are int he 70s for daytime but it can dip down to the 50s in the evening so I layer so that I can ride with the top down. and my wife likes it way warmer than me so I often have a layer to get rid of when she cranks the heat to 85. In these in between months I usually go for a tank top (not undershirt) and a long sleeve lightweight shirt for road trips. Then a Harrington as a top layer. Or a short sleeve button up and a fleece zip up jacket. I always keep a sweatshirt in the jeep for an extra layer if needed. But just for every day, not really.