Weather in September
September in
Kópavogur commences the initial phase of autumn, as the warmth of the sea regress to a cooler 9.8°C (49.6°F). Decreased daylight hours accompany this gradual temperature shift, as the summer's residual effervescence begins to dim. The likeness of the weather to the upcoming
October further instills the autumn atmosphere, gradually unpacking colder, darker days.
Sea temperature
In September, the average sea temperature is 9.8°C (49.6°F).
Note: With the appropriate swimsuit, one can swim in 9.8°C (49.6°F) even if temperatures dip below 10°C (50°F); otherwise, be ready for cold shock and breath issues. A fleeting swim around 13°C (55.4°F) is distressing.
Daylight
In Kópavogur, the average length of the day in September is 13h and 1min.
On the first day of September in Kópavogur, sunrise is at 06:12 and sunset at 20:42. On the last day of the month, sunrise is at 07:35 and sunset at 18:59 GMT.