Any day is best to go, just bring a hoodie or jacket! The Space Center is near the ocean, so it will be very windy! You can actually purchase tickets the day of! Try getting there early though, if not the lines will be long.
You don't need to buy in advance. It might save if you do. You might get a discount.
We bought tickets nearly two weeks in advance. Then as it drew closer we were able to adjust our reservation by 24 hours due to weather concerns with beach days planned later that week. Called the reservation line and since they were not at capacity those two days they switched them for us.
My mom in law bought hers online from her work the night before. They are not very busy so you should be ok buying it over there in the morning. Make sure you book the bus tour right away when you pay for your tickets. They only run so many bus tours a day and it is so worth it.
We went yesterday (a Wednesday during Spring Break) and bought the tickets the day we went.
We were there 2 weeks ago, just drove up and purchased tickets at the machine. Wear comfortable shoes,lots of walking and bring a jacket or sweater in case it gets windy. They close at 4 pm, so make sure you get there early to have time to see everything or most of it. We did not go on the weekend,I believe we went on Wednesday, so not too many ppl. Have fun and enjoy whenever you go.
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