31-40 degrees. in southern california, in the winter, lots of early morning rides in the foothills, lower mountains or deserts will start in that range and warm up
25-35 degrees so layering stuff and a windbreaker that compacts nicely are huge. will usually try to bring a mix of full finger gloves, glove underliners, regular gloves,
a warm skull cap, cycling cap, neck gaiter, arm warmers and either that windbreaker or medium weight jacket that doesn't compact. it can be a tough balance
depending on wind, how much effort you're putting out, how much it's actually warmed up, if you're in and out of the shade and if you can be bothered to stop
and take the minute-3 minutes to make the change(s). how much annoyance can you take before pulling over (or trying to make changes while moving)?
i usually end up opting for overheating so that i only have to make one longer change.