I'm the same way, but it's still possible to cover all bases for 3 season camping with well under 20lbs of gear. And if your load is that light you can also ride a bike that's in the 20lb range.
+1
I figure that pretty much any good list allows for some cold weather and the possibility of rain. On long tours especially ones with some portion of them in the mountains a few cold nights and probably some rain are a given. That doesn't necessarily mean that much bigger of a load.
Even with frost a lot of nights and at least one night with an overnight low in the teens I was fine with my normal summer kit on the Southern Tier in February. That is with a base load that might range from 10-15 pounds depending on what luxuries I take (second pair of shoes, bigger heavier camera, etc.).
I have a newer proposed list with a few more gram counter specific items that even goes a fair amount lighter that should still good for some iffy weather.