Keflavík Weather in May
Average highs run from 6°C on May 1 to 10°C on May 31, and lows from 3°C to 6°C. Normal precipitation for the month is 87 mm over about 16 wet days.
May day by day
The normal high and low for each date, in °C.
- Normal low
- Normal high
- Reanalysis extreme high
- Reanalysis extreme low
May at a glance
- Average high
- 8°C
- Average low
- 4°C
- Precipitation
- 87 mm
- Reanalysis high
- 15°CMay 30, 1991
- Reanalysis low
- -3°CMay 1, 2013
- Daylight
- 16 h 49 min to 19 h 58 min
- Cloud cover
- 75%
- Humidity
- 83%
- Dew point
- 3°C
- Wind
- 18.7 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 |
|---|---|---|---|---|---|
| May 1 | 6°C | 3°C | 11°C 2019 | -3°C 2013 | 51% |
| May 2 | 6°C | 3°C | 9°C 2011 | -2°C 2013 | 50% |
| May 3 | 7°C | 3°C | 11°C 2011 | -1°C 2003 | 50% |
| May 4 | 7°C | 3°C | 9°C 2008 | -1°C 2003 | 50% |
| May 5 | 7°C | 3°C | 10°C 2017 | -2°C 1997 | 49% |
| May 6 | 7°C | 3°C | 13°C 2017 | -2°C 1997 | 49% |
| May 7 | 7°C | 3°C | 13°C 2006 | -1°C 2015 | 50% |
| May 8 | 7°C | 3°C | 14°C 2006 | -2°C 2015 | 49% |
| May 9 | 7°C | 4°C | 14°C 2006 | 0°C 1992 | 49% |
| May 10 | 7°C | 4°C | 10°C 1999 | 0°C 1992 | 48% |
| May 11 | 7°C | 4°C | 10°C 2011 | -1°C 2015 | 46% |
| May 12 | 7°C | 4°C | 11°C 1996 | 0°C 2015 | 44% |
| May 13 | 7°C | 4°C | 12°C 1996 | -1°C 2012 | 44% |
| May 14 | 8°C | 4°C | 11°C 1996 | -2°C 2012 | 44% |
| May 15 | 8°C | 4°C | 11°C 2009 | -1°C 1993 | 44% |
| May 16 | 8°C | 4°C | 12°C 2009 | 0°C 2012 | 44% |
| May 17 | 8°C | 4°C | 13°C 2009 | 1°C 1993 | 46% |
| May 18 | 8°C | 4°C | 11°C 2009 | 1°C 2005 | 46% |
| May 19 | 8°C | 4°C | 11°C 2009 | 1°C 2000 | 46% |
| May 20 | 8°C | 4°C | 10°C 2003 | 1°C 2011 | 47% |
| May 21 | 8°C | 5°C | 12°C 2017 | 0°C 2006 | 48% |
| May 22 | 8°C | 5°C | 11°C 2019 | -1°C 2006 | 48% |
| May 23 | 8°C | 5°C | 12°C 2020 | 1°C 2006 | 47% |
| May 24 | 9°C | 5°C | 13°C 2010 | 1°C 2006 | 47% |
| May 25 | 9°C | 5°C | 12°C 2002 | 1°C 2006 | 48% |
| May 26 | 9°C | 5°C | 12°C 2002 | 1°C 2007 | 48% |
| May 27 | 9°C | 5°C | 12°C 2010 | 2°C 2007 | 48% |
| May 28 | 9°C | 6°C | 13°C 2004 | 2°C 1993 | 48% |
| May 29 | 9°C | 6°C | 13°C 2012 | 2°C 2019 | 48% |
| May 30 | 9°C | 6°C | 15°C 1991 | 2°C 2000 | 46% |
| May 31 | 10°C | 6°C | 14°C 2012 | 1°C 2000 | 47% |
Chance of rain
- Chance of a wet day
Sunrise and sunset
Times for 2026, local time (GMT).
- May 1
- sunrise 5:04 AM, sunset 9:53 PM
- May 31
- sunrise 3:30 AM, sunset 11:28 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.