Keflavík Weather in September
Average highs run from 11°C on September 1 to 8°C on September 30, and lows from 8°C to 5°C. Normal precipitation for the month is 147 mm over about 21 wet days.
September day by day
The normal high and low for each date, in °C.
- Normal low
- Normal high
- Reanalysis extreme high
- Reanalysis extreme low
September at a glance
- Average high
- 10°C
- Average low
- 7°C
- Precipitation
- 147 mm
- Reanalysis high
- 16°CSep 2, 2008
- Reanalysis low
- 1°CSep 30, 1994
- Daylight
- 14 h 33 min to 11 h 27 min
- Cloud cover
- 78%
- Humidity
- 86%
- Dew point
- 6°C
- Wind
- 20.2 km/h
Every day of the month
A wet day has at least 1 mm of precipitation in the reanalysis.
| Date | Normal high | Normal low | Reanalysis high | Reanalysis low | Chance wet |
|---|---|---|---|---|---|
| Sep 1 | 11°C | 8°C | 14°C 2006 | 5°C 1992 | 68% |
| Sep 2 | 11°C | 8°C | 16°C 2008 | 5°C 1992 | 69% |
| Sep 3 | 11°C | 8°C | 14°C 2006 | 3°C 1992 | 69% |
| Sep 4 | 11°C | 8°C | 14°C 2010 | 4°C 1992 | 70% |
| Sep 5 | 11°C | 8°C | 14°C 2016 | 4°C 1992 | 70% |
| Sep 6 | 11°C | 8°C | 13°C 1998 | 4°C 2005 | 70% |
| Sep 7 | 11°C | 8°C | 13°C 2010 | 3°C 2005 | 68% |
| Sep 8 | 11°C | 8°C | 14°C 2010 | 4°C 2012 | 66% |
| Sep 9 | 10°C | 7°C | 13°C 2003 | 4°C 1999 | 65% |
| Sep 10 | 10°C | 7°C | 13°C 2010 | 3°C 2011 | 64% |
| Sep 11 | 10°C | 7°C | 14°C 2008 | 4°C 2011 | 64% |
| Sep 12 | 10°C | 7°C | 13°C 1993 | 3°C 1997 | 64% |
| Sep 13 | 10°C | 7°C | 13°C 2002 | 3°C 1997 | 65% |
| Sep 14 | 10°C | 7°C | 13°C 2006 | 3°C 2007 | 64% |
| Sep 15 | 10°C | 7°C | 12°C 2015 | 3°C 2007 | 65% |
| Sep 16 | 10°C | 7°C | 12°C 2017 | 3°C 2007 | 65% |
| Sep 17 | 10°C | 7°C | 13°C 1996 | 3°C 1997 | 65% |
| Sep 18 | 10°C | 7°C | 12°C 1996 | 2°C 2000 | 65% |
| Sep 19 | 9°C | 6°C | 12°C 2006 | 2°C 2000 | 66% |
| Sep 20 | 9°C | 6°C | 13°C 1999 | 3°C 2018 | 66% |
| Sep 21 | 9°C | 6°C | 13°C 1999 | 2°C 2018 | 66% |
| Sep 22 | 9°C | 6°C | 11°C 1999 | 2°C 2003 | 68% |
| Sep 23 | 9°C | 6°C | 12°C 2019 | 2°C 2005 | 68% |
| Sep 24 | 9°C | 6°C | 12°C 2000 | 1°C 2005 | 69% |
| Sep 25 | 9°C | 6°C | 12°C 2019 | 1°C 2005 | 70% |
| Sep 26 | 9°C | 6°C | 12°C 2019 | 2°C 1994 | 70% |
| Sep 27 | 9°C | 6°C | 12°C 2019 | 2°C 1994 | 69% |
| Sep 28 | 8°C | 6°C | 11°C 2019 | 1°C 2005 | 68% |
| Sep 29 | 8°C | 5°C | 12°C 1992 | 1°C 2005 | 68% |
| Sep 30 | 8°C | 5°C | 12°C 2001 | 1°C 1994 | 67% |
Chance of rain
- Chance of a wet day
Sunrise and sunset
Times for 2026, local time (GMT).
- September 1
- sunrise 6:13 AM, sunset 8:46 PM
- September 30
- sunrise 7:36 AM, sunset 7:03 PM
Other months
Sources
Cloud, humidity, wind and sunshine, and temperature and precipitation: NASA POWER (MERRA-2, CERES and GEWEX SRB), 1991-2020. The data was obtained from the National Aeronautics and Space Administration (NASA) Langley Research Center's Prediction Of Worldwide Energy Resources (POWER) project funded through the NASA Earth Science Division: POWER Daily API v2, accessed 2026-09-25. Sun and moon: computed with the NOAA solar equations and Meeus.