We were planning a visit to Volcano Bay this weekend and now the weather report is looking like it will be in the high 40’s when we arrive in the morning and will hit the low 60’s after lunch in the mid afternoon. Will this be too unpleasant? I don’t mind being in heated water (which the Universal phone attendants keep touting) but really we aren’t talking about that. We are talking about standing around most of the time while wet in lines, etc. right? I know they have the virtual lines but I have been reading you still stand in a 20-30 min physical line even with this system.
I’ll be curious to hear how your experience is if you choose to go. We’re going in early January and worried about the same thing.
60 degrees I might be able to do, but 40 - no way. On the plus side, if it’s that chilly, you’ll probably have pretty low crowds - but if it’s too chilly, they may decide to not open the park…
Another possibility would be to get full-length “swim skins”; as far as I know, they’re allowed on the slides.
I see that WDW is closing Typhoon Lagoon for Friday and Saturday due to low temps. Maybe Volcano Bay will follow suit. Typhoon Lagoon Water Park Closed Due to Cold Weather on Dec. 9 - Orlando Theme Park News
It was in the 50’s all day today here in Austin, Texas and no way am I going to a waterpark in this weather! We’re going to Animal Kingdom instead! 
Thank you all for your responses!
Agree, I would “worry” they’d close if the temps were anywhere close to the 40s.
Also agree that you won’t be waiting in line very long in temps lower than 65!
Today the lows for Sat and Sun are supposed to be in the high 30s with highs in the 50s on Sat and highs in the low 60s on Sunday. Just getting worse! No matter what the temperature, Animal Kingdom will still be enjoyable! We haven’t seen Pandora yet or Rivers of Light (though we saw the Jungle Book show last summer 2016) so there will still be something new for us and we’ll just make a special stop for Volcano Bay next time. There’s always a next time with us! 
Disney changed Friday back to a day TL is open.