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Belfast in September

Find out everything about the water temperature in Belfast in September. Average, minimum and maximum recorded temperatures as well as daily temperature in September for the last two years. Compare the current month's sea temperature data with other months of the year.
Water temperature in September
Minimum:

57.9 °F

Average:

63.6 °F

Maximum:

69.5 °F

Sea water temperature in Belfast in September

In the city of Belfast, the month of September is somewhat too cool for swimming. The minimum recorded temperature during this month was 57.9°F on September 28, 2023, with an average temperature being 63.6°F and a maximum temperature reaching 69.5°F on September 2, 2022.

Most people would find such water temperature somewhat too cold for swimming. Throughout the month of September, the sea temperature gradually gets colder. Starting with an average temperature of 65.5°F at the beginning of the month, it steadily decreases to around 61.6°F by the end.
Date 10 years average 2024 2023
Sep 1 66.1°F 64.9°F 64.9°F
Sep 2 66.0°F 66.8°F 64.2°F
Sep 3 65.7°F 66.8°F 62.9°F
Sep 4 65.5°F 66.1°F 63.9°F
Sep 5 65.5°F 66.4°F 63.6°F
Sep 6 65.4°F 66.5°F 62.7°F
Sep 7 65.4°F 64.9°F 63.1°F
Sep 8 65.1°F 62.5°F 63.1°F
Sep 9 65.1°F 63.5°F 64.8°F
Sep 10 65.2°F 64.8°F 65.4°F
Sep 11 65.0°F 64.2°F 65.8°F
Sep 12 64.8°F 64.3°F 65.4°F
Sep 13 64.0°F 64.0°F 65.4°F
Sep 14 63.8°F 63.5°F 65.1°F
Sep 15 64.0°F 63.7°F 65.3°F
Sep 16 63.6°F 63.9°F 65.0°F
Sep 17 63.6°F 64.1°F 65.8°F
Sep 18 63.6°F 65.2°F 64.9°F
Sep 19 63.3°F 64.5°F 64.5°F
Sep 20 63.2°F 65.7°F 64.7°F
Sep 21 62.8°F 64.6°F 64.2°F
Sep 22 62.4°F 63.6°F 62.3°F
Sep 23 62.2°F 62.9°F 62.2°F
Sep 24 62.0°F 62.5°F 61.2°F
Sep 25 61.7°F 62.0°F 62.1°F
Sep 26 61.3°F 61.1°F 60.9°F
Sep 27 60.9°F 60.7°F 59.6°F
Sep 28 60.8°F 60.5°F 57.9°F
Sep 29 61.3°F 62.7°F 59.5°F
Sep 30 60.8°F 61.2°F 59.1°F

Sea water temperature in Belfast by month

In an average year, Belfast offers no days when the water temperature is warm enough to swim comfortably. The warmest water in Belfast was recorded on August 12, 2020, reaching a 73.6°F. While the coldest temperature occurred on January 1, 2018, dipping to 32.0°F. The average readings by season are 33.2°F in Winter, 36.3°F in Spring, 61.3°F in Summer, and 55.0°F in Autumn. September's average temperature is a slight drop from August's average of 68.2°F. In October, the temperature is expected to decrease further, potentially averaging around 56.6°F.