Check tire pressure after driving and warming the tires up. Once tires are sufficiently warmed make sure pressure is at recommended for car inside driver door sticker.

I asked a car buff friend about this. I get tired of adding air when the temp falls 50 degrees or so. I always have to do it the first true cold snap of the year, but after that it's fine. He puts nitrogen in his. Problem solved (for a cost though).

You should check your tire pressure monthly, it goes down 1 to 2 pounds for every 10 degrees of temperature change.

The TPMS are incredibly inaccurate and a really stupid gizmo to put in tires. They just add one more light to your dashboard. It's better to check your tire pressure yourself and take the car in to get the light turned off.

The technology is so-so and the physical conditions of the TPM basically destroys them pretty quickly.

Even with the cold weather, your tire pressure light probably shouldn't have come on. Was one tire way lower in pressure than the others? If so, you might have a slow leak.

Yes, you should add air in the winter as needed. Do not add and remove air every time you come and go. Just add air so that it's at the recommended PSI. A few pounds over the limit is fine, but you don't want it under the limit. If you find you have to keep adding air more than once or twice a year, then there's something wrong with your tires.

You should carry a gauge and check your tire pressure regularly, cold or not.

This and checking oil used to be standard when you got gas.

Add more air and see what happens.

Your tire pressure signal should NOT come on and off throughout winter.

I do add more air to my tires in the winter when it gets cold.

My TPMS light (tire pressure monitoring system) came on this morning and what I learned is that you are supposed to adjust your tire pressure according to the weather. But I'm confused... The website says that if you house the car in a garage then drive into the cold an adjustment needs to be made. What if I'm in and out of the garage, are they suggesting that I need to adjust the pressure each time I either enter or leave? Obviously I know that's not the case but help me understand what I need to do. Just adjust once and then again when the weather is warmer?

http://drive2.subaru.com/Spr05_WhatsInside.htm