First "cold" day in Orlando, Florida and my tire pressure light came on.
 

And by cold I mean 60~F lol it's Florida.

Anyways, my tire pressure light came on this morning. I didn't get a chance to check what the psi in the tires were since I had to go to work. I read online weather temperature affects psi so I was wondering if they are below 30psi, should I go ahead and fill them up now? I think for the next few days in Orlando it will be 50-60 degrees F in the mornings and back to 80s in the afternoon. I'm sure by next week it'll be 80-90 degrees throughout the day lol

Not only will temperature fluctuations change your tire pressure, but tires will also typically lose up to 2 psi a month just from simple air permeation through the innerliner.
I would check your pressure and keep it up to spec. If it gets hot out, just check again, you might not need to let any air out by then.

Every 10 degrees will gain/lose you about 1 PSI. It's perfectly normal for folks to have the TPMS light come on when the winter season arrives. You need to fill the tires to the proper, 35 PSI rating, at a temperature that makes sense for your climate. In other words, if you have a few days 30 degrees below average, don't fill your tire son those days or they will be over-inflated by about 3 PSI when the temperatures climb back up.

Basically, tires need a few more PSI of air in the winter, as they lose a few PSI due to the temperature change, as well as slow leakage over time, as mentioned earlier. The TPMS is letting you know this.

Checking in from Orlando, FL here.... *currently wearing Advan Racing hoodie*

But yeah, very normal for your light to come on with this change of weather.

TPMS light comes on, indicating low tire pressure: What do I do?
Check tire pressure, add air accordingly.

I am also in Florida, if we have a cold snap I don't bother with the pressures. If I know it's going to be cold for an extended time then I will make the adjustment. This is the problem with simply having a light. There has to be some threshold for when it turns on but that doesn't mean your tire is going to blow. I really wish we had actual pressures listed for each tire. I can read them in Techstream so I know it's possible to get via OBD2. I would love it if someone could figure out the PIDs needed to read the pressures in Torque or something.

Yes, add air for now. When you're in hot weather, check the tire pressure again and adjust accordingly.

Best practices indicate that should check tire pressure regularly regardless of whether the TPMS comes on. I always keep a pencil tire pressure gauge in the car

In my experience if you TPMS comes on because of the temp change that just means you were underinflated to begin with, but not enough to turn the light on. They don't come on 1PSI under expected pressure. It comes on at 25% under. So at 35PSI expected the light comes on at 26.25PSI (probably at under 27).

So, put air in the tire you needed it anyway, you just didn't know it.

I agree with this statement in general, but want to show that it is possible to have underinflation due to weather only (and not simply because the tire was already underinflated).

I have experienced this personally, though the issue does not come up overnight. I'm not always 100% diligent with checking my tire pressure, so I have had temperature-induced underinflation occur. However, my situation is somewhat unique since the temperature change across seasons is very severe in my area (California High Desert - 110 F summer highs, 20 F winter lows). Obviously, as it warms up from the winter, I need to do the opposite and start letting air out.

In the end, the moral is to be diligent about maintaining your car no matter what the season is.

agreed there are a lot of variables that come into play but as a rule of thumb in "normal" temperature ranges, you probably just need to put some air in the tires and move on.

You're thinking about it too much. Your TPMS light is on, check your tire pressures.

Did anyone mention checking the tire pressure yet?

Tire pressure should always be maintained based on ambient temperatures. So when the weather changes, you should check the pressure.

~29 psi triggered the TPMS light on my 2017

I think a lot of people missed the part where I said, "I didn't get a chance to check what the psi in the tires were since I had to go to work." I figured I'd get a discussion going while I'm at work until I got off to actually check.