September weather forecastSeltjarnarnes, Iceland

September

Weather in September

September in Seltjarnarnes embodies the onset of fall, a noticeable contrast to the summer warmth of August. The average sea temperature starts to retreat to a cooler 9.7°C (49.5°F) indicating the arrival of the fairly milder months. Length of daylight noticeably diminishes from August, reflecting the typical autumn--a shift as September progresses. Even though September ushers in a coolness signaling the start of fall, October's weather magnifies this change.

Sea temperature

In Seltjarnarnes, the average seawater temperature in September is 9.7°C (49.5°F).
Note: In 9.7°C (49.5°F), cold shock and rapid breathing can occur when swimming at temperatures below 10°C (50°F).

Daylight

The average length of the day in September is 13h and 1min.
On the first day of the month, sunrise is at 06:12 and sunset at 20:43. On the last day of September, in Seltjarnarnes, sunrise is at 07:35 and sunset at 18:59 GMT.

Updated: Feb 10, 2024
Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

In September, the average sea temperature is 9.7°C (49.5°F). At temperatures below 10°C (50°F), swimming in a suitably protected swimsuit is feasible; otherwise, cold shock and loss of breathing control are imminent. Even a short swim, without thermal protection, at temperatures around 13°C (55.4°F) is not comfortable.

The average day length in September in Seltjarnarnes, Iceland, is 13h and 1min.

In September, on the first day of the month, sunrise is at 06:12 and sunset at 20:43. On the last day of the month, sunrise is at 07:35 and sunset at 18:59 GMT.

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Average sea temperature

Average daylight

Average sea temperature in September
Seltjarnarnes, Iceland

Average sea temperature in September: 9.7°C

The best months for swimming (with the highest average sea temperature) are July and August (11.3°C).
The coldest month (with the lowest average sea temperature) is March (4.3°C).

Average daylight in September
Seltjarnarnes, Iceland

Average daylight in September: 13h and 0min

The month with the longest days is June (Average daylight: 20h and 54min).
The month with the shortest days is December (Average daylight: 4h and 24min).