Weather in Reykjavik in September 2025
Average weather
Average temperature in Reykjavik in September
The expected average maximum temperature in September is +11°C with a maximum of +14°C and a minimum of +1°C.
The average maximum temperature goes down 23% by the end of the month, compared with the beginning of the month, from +13°C to +10°C.
Is Reykjavik warm or cold in September?
Reykjavik is typically cool in September.
Maximum temperatures go down compared to the previous month from +14°C to +11°C. The minimum temperature also goes down from +9°C to +6°C.
Pack a sweater and a jacket as there will be cooler temperatures.
Take a look at how September is compared to other months in Reykjavik:
Water temperature in Reykjavik in September
Water in Reykjavik in September is Cold. It varies from +8°C to +11°C, with an average of +10°C. This is almost similar to the air temperature, which averages +11°C.
The water temperature in September is one of the warmest of the entire year:
Can you swim in Reykjavik in September?
Climate in Reykjavik in September
| August | September | October | ||||
|---|---|---|---|---|---|---|
| Avg. temperature | ||||||
| +14°C | +11°C | +7°C | ||||
| Min. temperature | ||||||
| +2°C | -3°C | -10°C | ||||
| Max. temperature | ||||||
| +24°C | +18°C | +15°C | ||||
| Rainfall | ||||||
| 87 mm | 98 mm | 86 mm | ||||
| Wind | ||||||
| 3 m/s | 4 m/s | 4 m/s | ||||
| Avg. water temperature | ||||||
| +11°C | +10°C | +8°C | ||||
| Humidity | ||||||
| 79% | 78% | 78% | ||||
| Air pressure | ||||||
| 1007 HPa | 1004 HPa | 1002 HPa | ||||
| Sunny days | ||||||
| 3 | 3 | 4 | ||||
| Cloudy days | ||||||
| 8 | 7 | 8 | ||||
| Rainy days | ||||||
| 20 | 20 | 16 | ||||
| Snowy days | ||||||
| 0 | 0 | 3 | ||||
September weather is still as ok as in August. It’s getting colder in September. From +14°C in the day, the average maximum temperature lowers to +11°C. Prepare for more rain. Average rainfall goes from 87 mm to 98 mm. It feels drier, as humidity decreases from 79% to 78%. Winds are stronger in comparison to August, going up from 3 m/s to 4 m/s on average. The amount of sunny days stay about the same, averaging 3 sunny days during the month.
October brings much the same weather, it remains ok.
Wind
The average wind speed is 4 m/s getting up to 11 m/s which is a medium breeze. You can feel it, especially getting out of the water.
The average wind speed in Reykjavik is gradually decreasing during September, going from 8 m/s to 5 m/s over the course of the month.
Rain
How was the weather last September in Reykjavik?
Climate Change over Years
The climate in Reykjavik in September has not changed much over the last 43 years.
The average temperature was the lowest in 1979 (+5°C) and the highest in 2003 (+9°C). The driest year was 2019 with only 289 mm of rainfall, and the wettest year was 2003 with 1379 mm.
FAQ
Is September a good time to visit Reykjavik?
Can you sunbathe in Reykjavik in September?
Can you swim in Reykjavik in September?
Is Reykjavik rainy in September?
Is it sunny in Reykjavik in September?
Monthly weather in Reykjavik
Source of the data
For this page, we’ve looked at the typical weather in Reykjavik, based on historical hourly weather data from January 1, 1979, to December 31, 2023.
For past dates, we show actual recorded data at the location at that time. Forecasts are based on recorded weather during that day of the year, averaged over the total years for which we have records (unless stated otherwise). The daily temperature is the highest recorded temperature in the shadow during that day.