Days of Air Frost – Annual Average
The days of air frost are recorded as the number of days where the air minimum temperature is less than 0˚C. Air frost is closely related to both altitude and sea temperature. Air frost mostly (but not exclusively) occurs during winter, and during these months the sea temperature regulates the air temperature due to its latent heat properties. The sea takes longer to heat up and cool down than the land, so the sea is still relatively warm from the summer temperatures and this influences land air temperature close to the coast. Inland the number of ground frost days is considerably greater, and increases with altitude to peak in the uplands.