I went in May 2003 and it was the seriously BEST time I've ever gone!!! It was late may... I've been to DW in June, July Aug and September and even March and May was the absolute best time. NOt too hot, but hot enough to get a nice tan. Not humid, crowds are very low, THE BEST! Didn't rain much, but when it did, it was nice and only rained for like 10 minutes. Then the sun was back out.