Originally Posted by spongebob218
Recommended pressure is actually 33psi, cold. The TPMS system must see at least 33psi to clear the warning light. Try setting the pressure to 35psi in all the tires and see if the light goes out. Maybe your gauge is slightly off.
Also, does the light flash for a minute when you start the car up and then stay on, or does it come on solid initially. If it flashes first, it means there is a fault and a code is stored. If it doesn't flash, then it just indicates low tire pressure.
Great answer, particularly about a possible high-reading gauge combined with the mistake on the recommended pressure resulting in not enough pressure in the tire to turn off the warning.
OP, you thought cold weather MIGHT have affected pressure - it definitely does. You have to check your pressures weekly even when the low temps are about the same every night because all tires leak a little. When the low is 10 degrees lower than the previous low, you have to check them again.
Always check tire pressure first thing in the morning before the sun hits the tires.