September weather forecast
Iceland

September ushers in the autumn season in Iceland, bringing cooler temperatures and the onset of more frequent precipitation. Average temperatures range from 7°C (44.6°F) to 11°C (51.8°F), a noticeable drop from the summer months. The southern and western coastal regions, including Reykjavik, still enjoy slightly milder conditions due to the moderating influence of the ocean.

In September, daylight hours reduce significantly, with the sun rising around 7 am and setting around 7 pm by the end of the month. The decreasing daylight marks a stark contrast to the endless summer days, as Iceland starts to experience darker nights, which makes it a favourable time for viewing the Northern Lights.

Precipitation in September is variable, averaging between 60mm (2.36") to 90mm (3.54"), and occurs primarily as rain. Increased rainfall, coupled with cooler temperatures, means that snow can begin to appear, especially in the northern regions and higher elevations. September can also be a windy month, with gusts averaging 14km/h (8.7mph), which can make the temperature feel cooler than it actually is.

September marks the start of the aurora season in Iceland. As the nights get longer, the opportunity to witness the spectacular Northern Lights increases. Although the weather can be unpredictable, with a mix of rain, wind, and potential snow, the chance to view this natural phenomenon is a significant draw for visitors.

Despite the shift towards cooler and potentially wetter weather, September remains an excellent month for outdoor activities, including hiking and sightseeing. The autumn landscape is a sight to behold, with vibrant hues of yellow, orange, and red adorning the foliage, contrasting with the country's blue lakes and rivers. The beauty of the changing seasons, coupled with the increasing chances of Northern Lights sightings, makes September an attractive month for those willing to brave the unpredictable weather.

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• Reykjavík - September »
  January, February and September, with an average relative humidity of 82%, are most humid months in Reykjavík, Iceland. Entering fall, the weather in Reykjavík, Iceland starts to cool in September, with an average high of 9.6°C (49.3°F) and the return of snowfall recorded at meager 0mm (0").
• Kópavogur - September »
  September in Kópavogur commences the initial phase of autumn, as the warmth of the sea regress to a cooler 9.8°C (49.6°F). In Kópavogur the average seawater temperature in September is 9.8°C (49.6°F).
• Akureyri - September »
  In Akureyri, in September, during 20.5 rainfall days, 72mm (2.83") of precipitation is typically accumulated. In Akureyri, in September, during 20.5 rainfall days, 72mm (2.83") of precipitation is typically accumulated.
• Akranes - September »
  On the first day of September in Akranes sunrise is at 06:09 and sunset at 20:46. The arrival of September in Akranes sees the onset of fall, as temperatures continue to drop, and daylight hours shorten.
• Selfoss - September »
  In Selfoss in September, during 18.7 rainfall days, 95mm (3.74") of precipitation is typically accumulated. On the first day of September in Selfoss sunrise is at 06:06 and sunset at 20:41.
• Ísafjörður - September »
  Yet, the splendid colors of autumn combined with the still mild weather keeps Ísafjörður notable. Ísafjörður marks the start of September with an average high-temperature of a frosty 9°C (48.2°F), hinting at a slight fluctuation from August's 11.9°C (53.4°F). In Ísafjörður, in September, the average water temperature is 7.4°C (45.3°F).
• Vestmannaeyjar - September »
  In Vestmannaeyjar in September, it is raining for 15.7 days, with typically 131mm (5.16") of accumulated precipitation. In Vestmannaeyjar the average seawater temperature in September is 10.3°C (50.5°F).
• Grindavik - September »
  On the first day of September in Grindavik, sunrise is at 06:13 and sunset at 20:46. On the first day of September in Grindavik, sunrise is at 06:13 and sunset at 20:46.
• Seltjarnarnes - September »
  In September, on the first day of the month, sunrise is at 06:10 and sunset at 20:45. September in Seltjarnarnes embodies the onset of fall, a noticeable contrast to the summer warmth of August.
• Borgarnes - September »
  In Borgarnes in September, during 17.8 rainfall days, 40mm (1.57") of precipitation is typically accumulated. In Borgarnes, Iceland, in September, it is raining for 17.8 days, with typically 40mm (1.57") of accumulated precipitation.