The solution is going to depend on how miserable you are about your snug balls. You could consult with cosmetic surgeons to see if anything can be done surgically but usually the opposite (balls that hang too low) can be corrected this way only. Some people suggest stretching the scrotum gradually or weighing it down but given there's a lot of sensitive tissues and muscles in the region, I don't recommend it. There is no proof that such activities provide a permanent solution either.

It sounds to me that you have efficient muscles down below that keep your balls tucked up. You'd need to see how low your balls do hang in warm weather and if it there's not much difference to how they are in the cold, I'm guessing that's how you're made.

If it helps, women aren't too concerned about whether balls hang low or not but if you are totally unhappy then it may be worth discussing your options with a cosmetic surgeon. I'd rather think that your snug balls are a good indication that your muscle tone is excellent and those assets are well protected.