That's good, but cold snakes tend to be more... sleepy I guess you could say, if he's cold he'll be way less active
It's not a bad thing per say, but you will want to raise his temp, and maybe do it gradually if he's cold. If it rises really fast and he's really cold, it could stress him out more. Again no worries though, you're getting it corrected
And snakemom85 is right, if you have a mesh top or "open" top, it loses humidity quicker. In the winter I cover up the top of my snakes enclosure with a wood board, tin foil also works great. If you find too much humidity is staying in, try a cloth (so it can "breathe")
Goodluck!