Do we know when it opens? Does it fluctuate year from year? If so, is there A website or phone number or something where I can check?

Saltrivertubing.com

Yes. It fluctuates by year.. July 4th is the 1st event when it opens. Stays open until 1st week of oct...you can float anytime you would like. But it is way to cold and not safe when there is noone out with u. There is a crew team that will be on boats when summer time hits.

If you have your own tube/boat you can float any time you want.

https://www.saltrivertubing.com/