I've found the most wallet-friendly approach is to try to acclimate. I wear the same bib shorts and short sleeve jerseys from "as hot as it gets" down to 50ºF. Some arm warmers and thicker socks down to around 40ºF. Convertible jacket with zip off sleeves also very handy-- some days just the action of a wind vest is enough-- keep the core insulated.

There were plenty of guys out this morning (low 60 temps) in the full winter regalia-- arm and leg warmers, jackets, full finger gloves. Insane. When actual winter comes (what we have of it here) those guys are gonna be sipping cocoa under an afghan on the sofa.