We Want to go to park tomorrow which is Thursday March 8th. Taking our niece. Will there be a chance for her to see manatee? I know it has been cooler the past couple of nights. Not sure if that helps bring more manatee in to park

You might luck out and see some there since it has been a bit cool out. Its not guaranteed.

There will be. There usually always there because the water that comes out of there is warm

The chance of seeing manatees is directly related to the surrounding area water temperatures. The Manatees will come to the park because they like the warmer water from the power plant discharge. I suggest you go enjoy the park as an adventure itself telling your niece you'll look for Manatees but may not see any.

With the cold front passing I would say yes

I would belueve so since its quite cold here now ...