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 »
  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"). On the first day of September in Reykjavík sunrise is at 06:11 and sunset at 20:42.
• Kópavogur - September »
  On the first day of September in Kópavogur, sunrise is at 06:12 and sunset at 20:42. 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).
• Akureyri - September »
  The shift from August to September in Akureyri includes a minor decrease in the average high-temperature, lightly dropping from a cool 10°C (50°F) to a chilly 6.9°C (44.4°F). On the last day of September, in Akureyri sunrise is at 07:21 and sunset at 18:42 GMT.
• Akranes - September »
  The arrival of September in Akranes sees the onset of fall, as temperatures continue to drop, and daylight hours shorten. The months with the highest humidity in Akranes, Iceland, are January, February and September, with an average relative humidity of 82%.
• Selfoss - September »
  On the first day of September in Selfoss, Iceland, sunrise is at 06:09 and sunset at 20:38. Selfoss, in the month of September, notes an average low temperature of 6.1°C (43°F), indicating a small decrease from the daytime highs.
• Ísafjörður - September »
  September welcomes an average high-temperature of a chilly 9°C (48.2°F), not much different from the preceding month. Ísafjörður maintains a consistent average nighttime low-temperature of 4.5°C (40.1°F) throughout September. In Ísafjörður, the average seawater temperature in September is 7.4°C (45.3°F).
• Vestmannaeyjar - September »
  On the last day of September, in Vestmannaeyjar, sunrise is at 07:28 and sunset at 18:53 GMT. In the month of September, Vestmannaeyjar experiences a minor discrepancy from peak daytime temperatures, settling at an average low-temperature of 5.9°C (42.6°F).
• Grindavik - September »
  On the first day of September in Grindavik sunrise is at 06:15 and sunset at 20:43. In Grindavik in September, it is raining for 19.9 days, with typically 86mm (3.39") of accumulated precipitation.
• Seltjarnarnes - September »
  On the last day of September, in Seltjarnarnes, sunrise is at 07:35 and sunset at 18:59 GMT. In September, on the first day of the month, sunrise is at 06:12 and sunset at 20:43.
• Borgarnes - September »
  The months with the highest humidity in Borgarnes are January, February and September, with an average relative humidity of 82%. Despite the reduction in daylight hours, September offers pleasant weather suitable for exploring the fall colors and majestic landscapes around Borgarnes.