Belfast
United Kingdom
Long-term weather forecast
Long-term weather forecast

May weather forecast and climate
Belfast, United Kingdom

A close-up view of the Northern Ireland City Hall located in Belfast, United Kingdom
A close-up view of the Northern Ireland City Hall located in Belfast, United Kingdom
May, the last month of the spring, in Belfast, is a mild month, with temperature in the range of an average low of 6.8°C (44.2°F) and an average high of 15°C (59°F).

Temperature

In Belfast, the average high-temperature in May slightly increases, from a cool 11.9°C (53.4°F) in April, to a mild 15°C (59°F). The average low-temperature, in May, is 6.8°C (44.2°F).

Rainfall

May is the month with the least rainfall in Belfast. Rain falls for 11.7 days and accumulates 57.3mm (2.3") of precipitation.

Sea temperature

In Belfast, the average seawater temperature in May is 10°C (50°F).
Note: Swimming in 10°C (50°F) is considered dangerous. Unprotected immersion in temperatures below 10°C (50°F) causes quickly maximum intensity cold shock with hyperventilation.

Daylight

The average length of the day in Belfast is 16.1h.

Sunshine

May has the most sunshine of the year in Belfast, United Kingdom, with an average of 6.4h of sunshine.

UV index

The average daily maximum UV index in May is 5. A UV Index value of 3 to 5 symbolizes a moderate threat to health from the exposure to the Sun's UV radiation for ordinary individuals.
Note: The daily maximum UV index of 5 interpret into the following advice:
Take precautions - Protection against sun damage is advised. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes.

What is the temperature in May in Belfast?

In May, in Belfast, United Kingdom, the average high-temperature is 15°C (59°F), and the average low-temperature is 6.8°C (44.2°F).

How many days does it rain in May in Belfast?

In Belfast, United Kingdom, during May, the rain falls for 11.7 days and regularly aggregates up to 57.3mm (2.3") of precipitation.

What is the driest month in Belfast?

The month with the least rainfall in Belfast, United Kingdom, is May when the rain falls for 11.7 days and typically collects 57.3mm (2.3") of precipitation.

How cold is the water in May in Belfast?

In May, the average sea temperature is 10°C (50°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.

How many hours of daylight does Belfast have in May?

In May, the average length of the day in Belfast, United Kingdom, is 16.1h.

What month has the most sunshine in Belfast?

With an average of 6.4h of sunshine, May has the most sunshine of the year.

How many hours of sunshine does Belfast have in May?

In May, the average sunshine in Belfast is 6.4h.

How high is the UV index in May in Belfast?

In Belfast, the average daily maximum UV index in May is 5. A UV Index estimate of 3 to 5 represents a moderate health threat from the exposure to the Sun's UV rays.
Average temperature in May - Belfast, United Kingdom
  • Average high temperature in May: 15°C

The warmest month (with the highest average high temperature) is July (18.8°C).
The month with the lowest average high temperature is January (7.1°C).

  • Average low temperature in May: 6.8°C

The month with the highest average low temperature is July (11.7°C).
The coldest month (with the lowest average low temperature) is February (1.6°C).

Average rainfall in May - Belfast, United Kingdom
  • Average rainfall in May: 57.3mm

The wettest month (with the highest rainfall) is October (89.6mm).
The driest month (with the lowest rainfall) is May (57.3mm).

Average rainfall days in May - Belfast, United Kingdom
  • Average rainfall days in May: 11.7 days

The month with the highest number of rainy days is January (14.8 days).
The month with the lowest number of rainy days is June (11.3 days).

Average sea temperature in May - Belfast, United Kingdom
  • Average sea temperature in May: 10°C

The best month for swimming (with the highest average sea temperature) is September (14.3°C).
The coldest month (with the lowest average sea temperature) is March (8°C).

Average daylight in May / Average sunshine in May - Belfast, United Kingdom
  • Average daylight in May: 16.1h

The month with the longest days is June (Average daylight: 17.2h).
The month with shortest days is December (Average daylight: 7.4h).

  • Average sunshine in May: 6.4h

The month with most sunshine is May (Average sunshine: 6.4h).
The month with least sunshine is December (Average sunshine: 1.5h).

Average UV index in May - Belfast, United Kingdom
  • Average UV index in May: 5

Months with the highest UV index are June and July (UV index 6).
Months with the lowest UV index are January and December (UV index 0).