Climate averages 1991–2020
Reykjavík weather
in September.
A cool, wet month: the 4th warmest and the wettest of the year.
Long-term climate patterns, not a forecast for a particular trip.
September is a cool month in Reykjavík: daytime highs average 10.3°C and nights cool to about 5.8°C. By daytime temperature it is the 4th warmest of the 12 months.
Expect about 126 mm of rain on roughly 17 days, which makes September a wet month (the wettest month of the year). Daylight, from sunrise to sunset, lasts about 13 h 08 min on an average September day.
The nearest other city in this atlas is Tórshavn (795 km away). In September its highs average 11.2°C, 0.9°C warmer than Reykjavík, with 94 mm of rain.
From September to October, average highs fall by 4.3°C to 6.0°C, and monthly rainfall falls from 126 mm to 111 mm.
The annual picture
September in context
Monthly precipitation
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
Reykjavík climate table
| Month | Average highHigh / low | Average low | Precipitation mm/month | Wet days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 1.0°C-3.7°C | -3.7°C | 124 | 17.9 | 5.55 h |
| February | 1.2°C-3.6°C | -3.6°C | 123 | 16.8 | 8.58 h |
| March | 2.4°C-2.7°C | -2.7°C | 114 | 16.9 | 11.712 h |
| April | 5.7°C0.0°C | 0.0°C | 90 | 15.3 | 15.015 h |
| May | 9.4°C3.3°C | 3.3°C | 83 | 14.8 | 18.418 h |
| June | 12.7°C6.8°C | 6.8°C | 69 | 12.8 | 20.821 h |
| July | 14.4°C8.7°C | 8.7°C | 76 | 13.3 | 19.720 h |
| August | 13.5°C8.2°C | 8.2°C | 93 | 14.9 | 16.416 h |
| September, selected | 10.3°C5.8°C | 5.8°C | 126 | 16.8 | 13.113 h |
| October | 6.0°C1.9°C | 1.9°C | 111 | 14.8 | 9.810 h |
| November | 2.7°C-1.1°C | -1.1°C | 113 | 15.5 | 6.67 h |
| December | 1.2°C-3.4°C | -3.4°C | 124 | 16.5 | 4.44 h |
Precipitation (rain or snow, as water) is the average of the 30 separate monthly totals. A wet day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
September in nearby cities
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Reykjavík) is explained once on the Reykjavík year overview and on the Sources, method and limits page.