The Science Behind Why Your Fingernails Grow Faster When You're Hot

Have you ever noticed you need to clip your toenails more during the summer? Maybe you thought you were just imagining things, or that your fixation on your summer pedicure had you seeing the need for nail clippers when none really existed. But it's true that your nails — including both your fingernails and toenails — grow more in warmer weather (via Nails Magazine). This strange quirk is the result of a confluence of different things, from increased blood flow to a higher consumption of fruits and vegetables.

According to Healthline, nails are made of keratin, which is a protein. Nail cells are dead, but they're produced by a bundle of living cells — something called the matrix, which is found at the base of your nail, near your nail bed, according to Informed Health. The root of the nail, the matrix continually produces new cells, from which the nail grows outward along the finger, according to Live Science.

Why blood supply is boosted in warmer months

One major factor at play is how temperature affects circulation, according to Nails Magazine. In colder weather, people experience reduced circulation and reduced blood flow to the fingers — which, in turn, means reduced blood flow to the nailbed and less growth. Other things can affect the blood flow to your nails, too, including exercise levels and what hand you use more, according to Healthline. In short, the more you do with your hand, the more blood flow it gets.

Vitamin levels also play a role in nail growth, helping your fingernails grow faster in the summer, according to Orangeville Foot Clinic. During the summer, you get more Vitamin D through fresh fruits and vegetables that you might be less likely to consume during the winter, which helps your nails grow quicker. Similarly, if you're spending the warm months out in the sun, you'll be getting more Vitamin D that way, too.

Other factors which affect nail growth

Apart from warm weather, your age and gender can affect how frequently you need to trim your nails, according to Healthline. Younger people have better blood circulation, which means faster nail growth. For less clear reasons, men's nails have also been observed to grow a little quicker than women's.

During periods of hormonal change, like puberty and pregnancy, nail growth also sees a significant boost, according to Healthline. On the other hand, being sick or having other conditions that affect circulation can inhibit your nail growth, the New York Times reports.

But the biggest factor that determines how fast your nails grow? Where they're located on your body. While your fingernails grow around three millimeters or 0.11 inches per month, that number falls to only one millimeter a month for toenails, according to Live Science. That means, regardless of the season, you're going to have to trim your fingernails around three times as often as your toenails.