We went the first Sunday in February (2015) and didn't encounter much for crowds. Popular rides had no more than a 10-15 minute wait at most; for most rides, my kids pretty much walked on in under 5 minutes. It was a very pleasant, relaxing day. The only thing I really didn't like about Legoland was the food --- I'd pack a picnic lunch if we ever went again -- but other than that, you really can't go wrong which ever day you pick.