Back in October, when I upgraded from the original iPhone 5 to my new iPhone 6 Plus, I entered the world of Touch ID for the first time. What a revelation. When it works, it’s a superb, almost magical experience—I want it for all of my devices, and for my desktop, too. When it works.

At first, I was perturbed by the fact that, once Touch ID is activated, you have to use it every time you want to unlock your phone. With previous models, I liked to set a long time interval before my passcode would be required to unlock my phone. That’s not entirely secure, I know, but I lock and unlock my phone so many times during the day that entering my passcode each time was a drag.

Over time though, I found Touch ID seemed to somehow get better at recognizing my thumbprint. I freely admit that might be my imagination, but I sincerely do believe that a month or so after having the phone, I was able to unlock it with Touch ID much more easily than before. Sometimes it worked so well that merely touching the phone’s home button instantly unlocked it when I only meant to just turn the screen on to see what notifications had arrived.

Then the weather got cold here in New York—very, very cold. Over the past few days I’ve found that Touch ID has gotten worse again. Now Touch ID frequently fails for me; I try it and I try it, and ultimately I have to enter my passcode in order to unlock the device.

My theory is that perhaps with the colder temperatures and heated indoor environments my skin is getting dryer, which is making my prints less conducive to Touch ID. This is consistent with my experience after washing my hands: when they’re dry and free of oil, Touch ID fails, and I have to lick a fingertip quickly to return some natural oil to the print, and then Touch ID works great again. However, a colleague says that he finds that the exact opposite to be true for him; when his fingers are dry it works better, and when they’re even the least bit wet, it fails. All the same, he agrees that the cold weather has made Touch ID much more problematic for him, too.

I learned today that you can actually “overtrain” Touch ID so that it is more tolerant of variations in your thumb presses. I tried it, but it didn’t help. Hopefully the weather will warm up around here soon, because this almost makes me want to turn off Touch ID altogether.