That should be fine if it stays that warm out. Is that the "low" night time temp. or the daytime one?

its the daytime temp still warming up though

Are you leaving the plants out overnight and what are the nighttime temperature lows? If you have a mixed collection of warm and cool growers it would be safest if you try to keep the nighttime temperatures as close to 15C as possible but temperatures as low as 10C are fine for many Hoyas. There are sensitive species as well so it's best to be cautious, cold wet conditions can cause problems for many warm loving plants.

Mike