Why do nails grow slower in winter? Because cold constricts the small blood vessels in your fingers, so slightly less blood reaches the nail matrix. The honest answer to why do nails grow slower in winter is less dramatic than it sounds: fingernails grow around 3 mm per month, and winter trims only a little from that.
It does seem slower, and by a small margin it is. What you mostly notice is a different problem. Cold air, indoor heating, and frequent hand washing leave nails dry and brittle, and a brittle nail splits before it gets long. The length goes missing at the tip, not at the root.
The numbers and most of the advice below come from a nail health expert. None of it promises faster growth. At Mirellé, we would rather give you a small honest number than a big hopeful one.
Do Nails Really Grow Slower in Winter?
Nails grow slightly slower in winter, and the slowdown is smaller than most winter advice suggests. Fingernails grow around 3 mm per month, and cold weather trims only a little from that. That is the short version of why do nails grow slower in winter.
One nail health expert is direct about the size of the effect: "Nails probably do grow a little more slowly during the winter, but the difference is pretty small." The expert adds that "any seasonal change is usually subtle."
Climate research points the same way. A 1958 study, summarized in what the research says about climate and nail growth, found slower growth in cold climates, though the mechanism is not firmly established. Summer growth likely runs a touch faster by the same logic, so be wary of any exact percentage quoted for the seasonal gap.
