We've been three times May/early June and would have no hesitation going back that time next year, school hols permitting. Trying October this year purely because first time I ever went in the 80s was October/November and wanted to try it again. Please don't let me down, October
May is a great time - mid-May is "normally" the best, because June starts bringing in the hurricane season and rainy afternoons.
The temps are high 80s, low 90s, humidity gets worse as the month goes on, but if you're heat lovers like my DH, you're gonna love it.
However, the weather can be unpredictable, so all I can do is relay what our weather was like

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It's not as busy in the parks as summer, but the end of the month sees lots of schools breaking up and visiting the parks for their last day, or whatever - sure there's a name for it in the US!
Yep, it can rain, but we found different levels of rain each trip. Mid-May - 5 mins of rain for the whole trip; end of May rained for 10-30 mins every afternoon with some cracking storms. However, if you're in the parks, stay put because loads of people head home when it rains . . . then when it stops it's quieter

. When we went in June we had rain for anything up to 2 hours for 3/4 of the afternoons, but again this we anticipated and really almost enjoyed - especially DH who is a lightening fan

. Our only mildly disappointment was our first ever trip to Busch gardens - it rained, thundered etc solid for 2 hours - and the storm was so bad we couldn't move at first out of respect of said lightening storm and were "trapped" under some hessian tarpauling in a bird enclosure

- don't like feathers, and we kept thinking it would stop soon, two hours later we ran for cover and bought most of the shops clothes, towels etc. 15 mins later once the sun had come out, the park was almost deserted and practically dry. Remember, we're used to rain here!
In fact the rain was almost a welcome cooling off period some afternoons.
It's not high season, so you can get some really good offers and discounts.
May - you'll love it (I hope

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