If you think the water coming out of your hose is cold in Florida ... don't move to Colorado! Alaska would be right out too.

City rec centers have showers too.

You can get adapters to connect a garden hose to a bathroom sink faucet. Any hardware store should have them. Some will work on kitchen sinks too - it depends on what type of faucet you have (the fancy kitchen faucets may not have screw-on threads you can access like most bathroom sinks). Throw the hose out a window, adjust the water temp, and use it out back.