If you don't have classpass you can sign up for a free trial (remember to cancel). I think it's one month free at the moment. Then you can sign up for gyms with open time or "gym time" where you can show up to use the gym and the amenities. For example, right now Republic Fitness allows you to come in for open gym time for a few credits.

I did this a few years back when the shower in my apartment was dropping like an IV drip and hopped around to different gyms and use their showers.