12/3/20
Can't speak to most of your questions....probably the whole state is tornado-prone, and quick google search should be able to locate information re. worst weather month
Been to two OK state parks...Lake Thunderbird (just went last week) and Keystone Lake (twice)...all trips over a Thanksgiving weekend...
Both are pretty standard state parks, with the expected atmosphere and amenities.as shown by the names, both are on a lake...both also have marinas (although Thunderbird's seems to be accessible only to slip renters)
Word of caution...the reservation system doesn't make it easy to tell what's on each site...we went with the Hog Creek loop at Thunrderbird, which we discovered upon arrival (to our disappointment) had water only every other site (a shared spigot) and our particular site was basically a blocked-off space at the edge of a parking lot...the other loops were traditional and have standard hookups