A few rambling thoughts.

I hiked yesterday in misty rain in Sequoia NP at about 7000 feet. I had a long sleeve oxy t, REI branded, and a Marmot windshirt (4 oz, polyester, water resistant) and a pair of nylon convertible pants on. When we stopped for lunch I put on a fleece jacket over the windshirt (wasn't raining just then). Temps were in the mid 50s with a high of 63F, feeling cooler because of the rain and fog.

Before I ramped up from once-in-a-while hikes to hiking a lot, hiking longer distances, and backpacking, I would have been a lot colder and required more insulation than that. I've noticed my cold and heat tolerance is different than it used to be; people are suffering from Fresno dry 90F heat while I am enjoying a beer on the back patio.

I currently plan to do a leg of the JMT with the windshirt, a poncho for rain protection, 200wt fleece, midweight base layer (synthetic), nylon pants, rain pants (for a warm layer or for hiking in heavy rain), and a synthetic long sleeved shirt. I will have extra socks and possibly an extra shirt. I have down quilts for use with my hammock, and will wrap up in one if temps drop at night before bed. I'm basing this on experience - I hike in the Sierras every weekend, except for the weekends I hike on the coast or have to work.

Consider what is comfortable for you and then plan to confront temps anywhere between 80F to 25F. I think experience allows you to take lighter gear, and your personal tolerances might let you take fewer layers, but it's hard to gauge where you are at in this - so go hiking in various conditions and see. Dayhikes are a great way to test gear and clothing.