Climate - Belfast (Northern Ireland)

The climate of Belfast is oceanic, with quite cold, rainy winters and mild, relatively rainy summers.
The city is the capital of Northern Ireland and is located on the east coast.

Winter, from December to February, is quite cold: temperatures are not so low, but wind and humidity can increase the sensation of cold. The sky is often cloudy, and rainfall is frequent. Sometimes, intense Atlantic depressions can cause wind storms.
Snowfalls are rare and not abundant. Usually, cold spells are not intense and do not last long. The temperature rarely drops below -5 °C (23 °F), however, it can occasionally drop to lower values. At Aldergrove airport (located outside the city, near Lough Neagh), the coldest record is -15 °C (5 °F) and was set in December 2010.

In spring, from March to May, the temperature slowly rises, and Atlantic fronts become a bit less frequent. In May, it is often still quite cold, especially in the first half of the month.

Summer, from June to August, is cool, with quite frequent rains.
Hot days are rare: the temperature may not reach 25 °C (77 °F) for an entire month, however, it can sometimes reach higher values. The highest record is 30.8 °C (87.4 °F) and was set in July 2022.

Autumn, from September to November, is gray, cloudy and rainy, and with each passing week, it gets progressively colder. In November, the wind is often moderate or strong.

Best Time

The best time to visit Belfast is the summer, from June to August, since it is the mildest of the year. The temperatures are generally good for outdoors activities, although it's better to bring an umbrella, and a sweatshirt or sweater for the evening or for cool days.

Belfast - Climate data

In Belfast, the average temperature of the coldest month (January) is of 4.7 °C (40.5 °F), that of the warmest month (July) is of 15.4 °C (59.8 °F). Here are the average temperatures.
In Belfast, precipitation amounts to 940 millimeters (37 inches) per year: so, it is at an intermediate level. It ranges from 65 mm (2.6 in) in the driest months (February, April, May, July) to 95 mm (3.7 in) in the wettest ones (October, November) Here is the average precipitation.
At Belfast, the sea temperature ranges from 7 °C (45 °F) in February, March to 15 °C (59 °F) in August. Here are the average sea temperatures.
In Belfast, there are on average around 1280 sunshine hours per year. Here are the average hours of sunshine per day.

Belfast - Weather by month

Based on the period 1991-2020

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In January, the coldest month of the year, the weather in Belfast is usually quite cold. The average temperature is of 4.7 °C (40 °F), with a minimum of 2.2 °C (36 °F) and a maximum of 7.2 °C (45 °F).
On the coldest nights of the month, the temperature usually drops to around -4 °C (25 °F). However, it dropped to -9.9 °C (14.2 °F) in January 2010.
On the warmest days of the month, the temperature usually reaches around 12 °C (53.5 °F). However, it reached 14.1 °C (57.4 °F) in January 2016.
Precipitation amounts to 90 mm (3.5 in), distributed over 15 days.
The day lasts on average 8 hours and 0 minutes.
There are on average 1.5 hours of sunshine per day. So, the sun shines 16% of the time.
The average humidity is 84%. Hence, the air is normally humid.
The average wind speed is 18 kph (11 mph).
The average sea temperature is of 8.5 °C (47 °F). Therefore, the sea is very cold for swimming.

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In February, the weather in Belfast is usually quite cold. The average temperature is of 5 °C (41 °F), with a minimum of 2.1 °C (35.8 °F) and a maximum of 7.9 °C (46.2 °F).
On the coldest nights of the month, the temperature usually drops to around -3.5 °C (25.5 °F). However, it dropped to -7 °C (19.4 °F) in February 2007.
On the warmest days of the month, the temperature usually reaches around 12 °C (53.5 °F). However, it reached 15.6 °C (60.1 °F) in February 2019.
Precipitation amounts to 65 mm (2.6 in), distributed over 12 days.
The day lasts on average 9 hours and 50 minutes.
There are on average 2.5 hours of sunshine per day. So, the sun shines 24% of the time.
The average humidity is 81%. Hence, the air is normally humid.
The average wind speed is 18 kph (11 mph).
The average sea temperature is of 7 °C (45 °F). Therefore, the sea is very cold for swimming.

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In March, the weather in Belfast is usually quite cold. The average temperature is of 6.4 °C (44 °F), with a minimum of 3.1 °C (37.6 °F) and a maximum of 9.7 °C (49.5 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around -2.5 °C (27 °F). However, it dropped to -6.9 °C (19.6 °F) in March 2001.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 14 °C (57.5 °F). However, it reached 19.8 °C (67.6 °F) in March 2012.
Precipitation amounts to 75 mm (3 in), distributed over 14 days.
The day lasts on average 12 hours and 0 minutes.
There are on average 3 hours of sunshine per day. So, the sun shines 26% of the time.
The average humidity is 78%. Hence, the air is normally humid.
The average wind speed is 17 kph (11 mph).
The average sea temperature is of 7 °C (45 °F). Therefore, the sea is very cold for swimming.

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In April, the weather in Belfast is usually quite mild. The average temperature is of 8.5 °C (47 °F), with a minimum of 4.7 °C (40.5 °F) and a maximum of 12.3 °C (54.1 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around -1 °C (30.5 °F). However, it dropped to -4.3 °C (24.3 °F) in April 1998.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 17.5 °C (63.5 °F). However, it reached 21.2 °C (70.2 °F) in April 2003.
Precipitation amounts to 65 mm (2.6 in), distributed over 11 days.
The day lasts on average 14 hours and 10 minutes.
There are on average 5 hours of sunshine per day. So, the sun shines 37% of the time.
The average humidity is 74%. Hence, the air is normally humid.
The average wind speed is 17 kph (10 mph).
The average sea temperature is of 8 °C (46.5 °F). Therefore, the sea is very cold for swimming.

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In May, the weather in Belfast is usually mild. The average temperature is of 11.2 °C (52 °F), with a minimum of 7 °C (44.6 °F) and a maximum of 15.3 °C (59.5 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around 1.5 °C (34.5 °F). However, it dropped to -1 °C (30.2 °F) in May 1996.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 21.5 °C (70.5 °F). However, it reached 25 °C (77 °F) in May 2012.
Precipitation amounts to 65 mm (2.6 in), distributed over 12 days.
The day lasts on average 16 hours and 10 minutes. So the days are long.
There are on average 6 hours of sunshine per day. So, the sun shines 37% of the time.
The average humidity is 72%. Hence, the air is normally humid.
The average wind speed is 16 kph (10 mph).
The average sea temperature is of 10 °C (50 °F). Therefore, the sea is very cold for swimming.

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In June, the weather in Belfast is usually mild. The average temperature is of 13.8 °C (57 °F), with a minimum of 9.9 °C (49.8 °F) and a maximum of 17.7 °C (63.9 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around 5 °C (41.5 °F). However, it dropped to 2 °C (35.6 °F) in June 1991.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 23.5 °C (74.5 °F). However, it reached 29.5 °C (85.1 °F) in June 2018.
Precipitation amounts to 70 mm (2.8 in), distributed over 11 days.
The day lasts on average 17 hours and 10 minutes. So the days are very long. June 21, the summer solstice, is the longest day of the year in the Northern Hemisphere.
There are on average 5 hours of sunshine per day. So, the sun shines 29% of the time.
The average humidity is 73%. Hence, the air is normally humid.
The average wind speed is 16 kph (10 mph).
The average sea temperature is of 12 °C (54 °F). Therefore, the sea is very cold for swimming.

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In July, the warmest month of the year, the weather in Belfast is usually very mild. The average temperature is of 15.4 °C (60 °F), with a minimum of 11.8 °C (53.2 °F) and a maximum of 19.1 °C (66.4 °F).
On the coldest nights of the month, the temperature usually drops to around 7 °C (44 °F). However, it dropped to 3.9 °C (39 °F) in July 2006.
On the warmest days of the month, the temperature usually reaches around 24.5 °C (75.5 °F). However, it reached 28.6 °C (83.5 °F) in July 2006.
Precipitation amounts to 65 mm (2.6 in), distributed over 11 days.
The day lasts on average 16 hours and 35 minutes. So the days are long.
There are on average 4.5 hours of sunshine per day. So, the sun shines 28% of the time.
The average humidity is 75%. Hence, the air is normally humid.
The average wind speed is 14 kph (9 mph).
The average sea temperature is of 14 °C (57 °F). Therefore, the sea is very cold for swimming.

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In August, the weather in Belfast is usually very mild. The average temperature is of 15.2 °C (59 °F), with a minimum of 11.6 °C (52.9 °F) and a maximum of 18.7 °C (65.7 °F).
On the coldest nights of the month, the temperature usually drops to around 7 °C (44.5 °F). However, it dropped to 4.2 °C (39.6 °F) in August 2020.
On the warmest days of the month, the temperature usually reaches around 23 °C (73 °F). However, it reached 28 °C (82.4 °F) in August 1995.
Precipitation amounts to 85 mm (3.3 in), distributed over 13 days.
The day lasts on average 14 hours and 50 minutes. So the days are long.
There are on average 4.5 hours of sunshine per day. So, the sun shines 31% of the time.
The average humidity is 77%. Hence, the air is normally humid.
The average wind speed is 14 kph (9 mph).
The average sea temperature is of 15 °C (59 °F). Therefore, the sea is cold for swimming.

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In September, the weather in Belfast is usually mild. The average temperature is of 13.2 °C (56 °F), with a minimum of 9.9 °C (49.8 °F) and a maximum of 16.6 °C (61.9 °F).
On the coldest nights, which normally occur at the end of the month, the temperature usually drops to around 4 °C (39 °F). However, it dropped to 0.2 °C (32.4 °F) in September 2007.
On the warmest days, which normally occur at the beginning of the month, the temperature usually reaches around 21 °C (70 °F). However, it reached 24.9 °C (76.8 °F) in September 1991.
Precipitation amounts to 75 mm (3 in), distributed over 12 days.
The day lasts on average 12 hours and 35 minutes.
There are on average 3.5 hours of sunshine per day. So, the sun shines 30% of the time.
The average humidity is 79%. Hence, the air is normally humid.
The average wind speed is 15 kph (9 mph).
The average sea temperature is of 14.5 °C (58.5 °F). Therefore, the sea is very cold for swimming.

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In October, the weather in Belfast is usually mild. The average temperature is of 10.2 °C (50 °F), with a minimum of 7.2 °C (45 °F) and a maximum of 13.1 °C (55.6 °F).
On the coldest nights, which normally occur at the end of the month, the temperature usually drops to around 1 °C (34 °F). However, it dropped to -3 °C (26.6 °F) in October 1992.
On the warmest days, which normally occur at the beginning of the month, the temperature usually reaches around 17 °C (63 °F). However, it reached 19.9 °C (67.8 °F) in October 1995.
Precipitation amounts to 95 mm (3.7 in), distributed over 14 days.
The day lasts on average 10 hours and 25 minutes.
There are on average 3 hours of sunshine per day. So, the sun shines 29% of the time.
The average humidity is 81%. Hence, the air is normally humid.
The average wind speed is 16 kph (10 mph).
The average sea temperature is of 13.5 °C (56.5 °F). Therefore, the sea is very cold for swimming.

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In November, the weather in Belfast is usually quite mild. The average temperature is of 7.0 °C (45 °F), with a minimum of 4.4 °C (39.9 °F) and a maximum of 9.7 °C (49.5 °F).
On the coldest nights, which normally occur at the end of the month, the temperature usually drops to around -1.5 °C (29 °F). However, it dropped to -8.6 °C (16.5 °F) in November 2010.
On the warmest days, which normally occur at the beginning of the month, the temperature usually reaches around 14 °C (57.5 °F). However, it reached 16.1 °C (61 °F) in November 2005.
Precipitation amounts to 95 mm (3.7 in), distributed over 15 days.
The day lasts on average 8 hours and 25 minutes.
There are on average 2 hours of sunshine per day. So, the sun shines 21% of the time.
The average humidity is 84%. Hence, the air is normally humid.
The average wind speed is 16 kph (10 mph).
The average sea temperature is of 12 °C (53.5 °F). Therefore, the sea is very cold for swimming.

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In December, the weather in Belfast is usually quite cold. The average temperature is of 5.0 °C (41 °F), with a minimum of 2.5 °C (36.5 °F) and a maximum of 7.6 °C (45.7 °F).
On the coldest nights of the month, the temperature usually drops to around -4 °C (24.5 °F). However, it dropped to -14.9 °C (5.2 °F) in December 2010.
On the warmest days of the month, the temperature usually reaches around 12.5 °C (54.5 °F). However, it reached 15.1 °C (59.2 °F) in December 2016.
Precipitation amounts to 90 mm (3.5 in), distributed over 14 days.
The day lasts on average 7 hours and 25 minutes. So the days are short. December 21, the winter solstice, is the shortest day of the year in the Northern Hemisphere.
There is an average of 1 hour of sunshine per day. So, the sun shines 15% of the time.
The average humidity is 85%. Hence, the air is normally humid.
The average wind speed is 16 kph (10 mph).
The average sea temperature is of 10 °C (50 °F). Therefore, the sea is very cold for swimming.