One thing to be aware of is that the first half of the hear includes "Jersey Week," when the NJEA holds their annual teachers convention for a few days and a sizable chunk of my lovely little state takes advantage to head down to Orlando. This is prominent enough that many planning sites and books factor it in (in fact, on some crowd calendars, you'll see most peaks associated with a named holiday or event, as well as this random, unnamed attendance bump in early November).
I was in Disney for Jersey Week in 2013, 2014, and 2016, and the crowds generally ranged from a 3 to a 7, depending on the park and the day. In 2015, with judicious use of FastPass+, we only had two waits of more than 20 minutes (one where we missed a cycle for a show, the other because we misjudged what Star Tours crowds would look like the month before the release of Episode VII). Most waits were 5-10 minutes, and many rides were essentially walk-ons.
The weather was hot on all three trips, generally upwards of 80. In 2014 and 2015, I believe there were multiple days that topped 90 degrees. Very little rain. Across all three trips, I think we got rained on maybe three times, with only one of them being a very heavy or prolonged storm.