How does cold weather affect the nails?
The nail grows slower in cold weather and faster in warm weather because circulation is slower in the cold weather, causing a growth slow down. If there is damage to the matrix, the nail may be deformed (thickened, brittle, etc.). You will see the nail growing out from the matrix and may see some of these changes as the nail grows. I don’t believe cold weather alone will damage the matrix and cause the nail to be brittle, unless there is some other health condition or trauma that may have affected the matrix along with the cold weather. — Dr. Dennis Arnold is head of the International Pedicure Association.