In the northern hemisphere, summer hasn't ended yet.
In California in particular, our scorching weather is just getting started.
It's most likely because the hotel set the thermostat low to save money if you find yourself in a hotel room.
That you just can't get cold enough for your tastes.
Personally, I don't blame them, and if I owned a hotel, I definitely would too.
Especially if there aren't even any people in the room.