Iceland Weather in September
September’s Reykjavík precipitation normal is 87.0 mm, compared with 64.5 mm in August. That change is a reason to plan for wet days, not to predict how much rain will fall during your stay.
September compared with the adjacent months
| Month | Average daily maximum | Average daily minimum | Monthly precipitation |
|---|---|---|---|
| August | 14.1°C | 8.6°C | 64.5 mm |
| September | 11.4°C | 6.2°C | 87.0 mm |
| October | 7.6°C | 2.7°C | 79.8 mm |
Source: WMO normals archived by NOAA (CSV), checked September 10, 2026. Temperatures are averages of daily highs and lows, not extremes. Precipitation is a monthly total, not the number of rainy days. This Reykjavík station does not represent every region or elevation.
Autumn routes and dark evenings
Make a route that still works if an inland hike drops out. Keep a lower-commitment alternative near your overnight base and check both road and trail conditions before leaving.
On September 10, 2026, SafeTravel advised against hiking Fimmvörðuháls because of dangerous conditions. That dated alert is a concrete reason not to describe September trails as generally open. Recheck the official notice for your own visit.
What to keep within reach
Bring a waterproof shell, insulation and dry layers for evening waits. If you go out for aurora, decide on a return time that preserves sleep before the next driving day.
Check the conditions for your day
- IMO weather forecasts: choose the region and forecast time.
- Road conditions and SafeTravel alerts: check the actual route and destination before departure.
- IMO aurora page: darkness and cloud cover matter alongside activity. Its sun-time panel is for Reykjavík.
For the wider comparison, see Iceland’s climate, August and October.
Planning help
September weather questions
Quick answers with safety notes where it matters.
How cold is Iceland in September?
Reykjavík’s 1991–2020 average daily maximum is 11.4°C and average daily minimum 6.2°C. These station normals describe historical averages, not the full range of possible temperatures or a forecast for all Iceland.
Is this a forecast for September 2026?
No. The table uses 1991–2020 climate normals. Check the Icelandic Meteorological Office forecast for the actual place and dates of your trip.
For monthly temperature and rainfall averages, explore the climate data in our Iceland statistics.