In the smartphone era, the journey from futuristic fantasy to everyday nuisance is short. When the Motorola Atrix 4G made phones with fingerprint scanners widely available in 2011, then when the iPhone 5S made them very widely available two years later, it was the sort of thing you would hungrily unpack the box to play with. Now, if a scanner gets your attention at all, it’s because the blasted thing won’t work.

Right now especially. For many people, it is a winter ritual to place a thumb on the sensor, then place it again, then again, then try a finger instead and ... oh, forget it, just pretend it’s still 2011 and enter the code! As Apple explains, and as we all know: “Moisture, lotions, sweat, oils, cuts or dry skin might affect fingerprint recognition.” So might “certain activities ... including exercising, showering, swimming, cooking”. Which is just a typically wholesome day, of course, in the life of an iPhone user.

Mysteriously, though, the cold weather problem can recur indoors, and no amount of drying or cleaning the fingertips will solve it. This is not because your phone is cold (although subzero temperatures can slow it down) or, per se, because your skin is. The issue here is cold weather actually changing your fingerprint enough to make it unrecognisable. This may in part be a matter of the tiny skin ridges stiffening temporarily. More often, it is a matter of your skin being dried and roughened by exposure to cold air, which alters the print shape and changes its conductivity. (The mechanics of optical, capacitative and ultrasonic fingerprint scanners are too complex to explain in the space available. This is a narrow escape because they are also too complex for me to understand.)

Happily, there are many possible solutions. One is to use a lot of hand cream, and try to keep your fingertips summery and youthful. Another is to teach your phone the “fingerprints” of your gloves. Indeed, there are gloves made specifically for this purpose. Some people have even found that you can record a nose print instead of a finger, although it is not clear that the skin on your nose is any more resilient. Probably the best solution overall is to install a new set of “winter fingerprints” with your worn fingers, much as you might switch to a winter wardrobe. And just as classy, I’m sure you will agree.