So I am very new to snake keeping and I absolutely love my about 4 month old Ball. Great Temper, good eater, etc.

On one side of my 40 gallon tank (yes I know this is big for a young ball, I have a lot of hides and plants for comfort), the hot side is regulated by an under tank heater and a thermostat, the ground temperature being about 95 degrees. I also have a dome lamp with a ceramic heater overhead to warm the air to what is a bit over 80.

However, my real problem is the cold side. It stays around 70-75 degrees which from what I read isn't appropriate. Sometimes the snake will stay around the cold side but moves back and fourth as it pleases (unsure of the gender right now). I don't think it is too uncomfortable because it still eats once a week and doesn't appear reckless in its tank. It just chills in hides.

Should I be worried? Is there anything I can do to fix this problem? It is also the winter time in NYC.