After participating in the DUI Dry Suit Rally at Beaver Lake, Arkansas I had a rude awakening (my own fault). If your regulator is not rated as "environmentally sealed" be sure you check the temperature ratings for that regulator. If you are one who has a different 1st stage, primary, and/or a different octo, you need to operate within the temperature limits of the highest temperature rating.
For example: if your primary or 1st stage is rated to 50 degrees and your octo is rated to 45, you should not exceed the rating of the primary or 1st stage being 50 degrees.
The reason for this is that as compressed air (at depth or going to depth) gets cooler (usually temps below 50 degrees) it can build up residual moisture within a tank. That residual moisture can make it to your 1st stage. Without an environmentally sealed unit, the residual moisture and colder temps can freeze up a unit due to the cold/moist air moving through a pressurized system at speed which causes even colder temps within the system.
If you`ve ever purged a tank, you know how easily it is to ice over a valve as well as the surface of the tank if you`re not being careful.
Your owners manual should have this information. If not, you should be able to contact the manufacturer to find out (websites may have this information).