In October, the weather in Keflavík is typically cold. Average daily high temperature in October is about 7 degrees above zero. On average, Keflavík has 23 rainy, 4 sunny, 3 cloudy, and 1 partly cloudy day in October. The rains are usually heavy. October as well as January, February, March, and April is considered the most uncomfortable time to visit Keflavík.