It really depends on what you want to do...if your going through the butterfly house that takes a bit more time and is not free. There are some other exhibits that also cost so plan accordingly.
I would say you could leisurely go through in 2-3 hours.
We did the free museum with 2 preteen girls in about 2.5 hrs
If you just walk through and at everything it'll take you to about an hour ,hour and half tops if you add the butterfly enclosure 2 hours if you have children then you're in there for the long haul.
One could easily spend a whole day there, there's so much to enjoy at that place!
Atleast 2 hours to see the whole museum. If you check out the butterfly exhibit and the scoop on poop that can be atleast 3 hrs and a half.
I'd say a good 3 hours, but it depends on whether you read the labels!
I would give yourself about 2 hours, more if you have kids who will participate in the activities they have available.
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