Iceland
Reykjavík in September: weather, sea & travel advice
This month's data profile
Rain shapes the decision
Reykjavík in September is climatically mixed. The average daily high is around 10 °C, and the sea is about 10 °C. With about 20 rainy days it is very wet.
Historical monthly averages, not a weather forecast. Individual days and years can differ substantially.
Rank among 12 monthly averages
17/100 · #6
Warmth
#4
Dryness
#10
Sun
#6
Sea warmth
#3
Published best categories: none
Reykjavík · SeptemberPhoto: rheins · CC BY 3.0Climate facts
- Average high
- 10 °C
- Average low
- 6 °C
- Sea
- 10 °C
- Rainy days (est.)
- 20 rainy days (est.)
- Sun (est.)
- 3 h/day
- Humidity
- 87 %
Climate evidence with direct month comparison
The highlighted row is the selected month. Precipitation total and rainy days are separate monthly averages.
| Month | Avg high °C | Avg low °C | Rainy days (est.) | Precipitation mm | Sun h/day (est.) | Humidity % | Wind m/s | Sea °C | Score |
|---|---|---|---|---|---|---|---|---|---|
| August | 13 | 8 | 18 | 126 | 4.4 | 86 | 2.2 | 11 | 26 |
| September (selected) | 10 | 6 | 20 | 164 | 2.6 | 87 | 2.7 | 10 | 17 |
| October | 6 | 2 | 18 | 146 | 1.2 | 90 | 3.1 | 8 | 13 |
How do the previous and next months compare?
Baseline: September (17/100)
Positive and negative values show the change from the selected month.
| Score Δ | Average high Δ | Average low Δ | Rainy days Δ | Rain Δ | Sun Δ | Humidity Δ | Wind Δ | Sea Δ | |
|---|---|---|---|---|---|---|---|---|---|
| August | +9 | +2.9 °C | +2.4 °C | -2.4 | -37.5 mm | +1.8 h | -1.9 % | -0.5 m/s | +1.3 °C |
| October | -4 | -4 °C | -3.4 °C | -2 | -18 mm | -1.4 h | +2.8 % | +0.4 m/s | -1.8 °C |
All twelve months in context
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Where to stay in Reykjavík
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Useful next decisions
Frequently asked questions
How warm is Reykjavík in September?
The average daily high is around 10 °C, with an average daily low of about 6 °C.
Can you swim in Reykjavík in September?
The sea is about 10 °C (cold).
Does it rain a lot in Reykjavík in September?
The curated estimate is about 20 rainy days per month, not a directly measured long-term average. Total precipitation averages around 164 mm for the month. A rainy day does not mean all-day rain.
When is the best time to visit Reykjavík?
No month in Reykjavík reaches the threshold for a clear recommendation in the climate score; the month comparison above shows the differences.