Outdoor pool is always open! I've never seen it shut down but the penguin answer is about right!
No joke, two weeks ago I saw 4 or 5 shirtless guys in their late 20s huddled together like penguins standing chest deep in the outdoor pool. I have no idea what they were doing, but it means the pool is open and it's too cold to swim in unless you're a penguin.
I believe it's open all year, but it's not heated. Water will be quite cold until temperature warms up.
Thanks! Your answer is awaiting moderation.