May weather forecast
Cardiff, United Kingdom

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Weather in May

May in Cardiff, United Kingdom, is characterized by the pleasant warmth and escalating daylight hours. Mild temperatures continue to rise in May to a maximum of 14.7°C (58.5°F), indicating the arrival of summer from the comfortably warm spring. This month, doused in sunlight, increases the lure of the seaside and the city's beautiful parklands. From barbecuing in the parks to cycling along the coast, May sees Cardiff abuzz with activities. As spring gives way to summer, Wales' capital city guarantees spectacular views and memorable adventures.

Temperature

Transitioning into May, Cardiff experiences an average high-temperature of a mild 14.7°C (58.5°F), marking a minor shift from the preceding month. An average low-temperature of 8.3°C (46.9°F) marks the month of May in Cardiff.

Humidity

April and May, with an average relative humidity of 81%, are the least humid months in Cardiff.

Rainfall

In Cardiff, in May, during 10.3 rainfall days, 15mm (0.59") of precipitation is typically accumulated. Throughout the year, there are 132.6 rainfall days, and 252mm (9.92") of precipitation is accumulated.

Snowfall

In Cardiff, snow does not fall in March through October.

Sea temperature

In Cardiff, the average seawater temperature in May is 11.3°C (52.3°F).
Note: Swimming in 11.3°C (52.3°F) at temperatures under 10°C (50°F) requires thermal swimsuits; otherwise, one can face cold shock and breathing difficulty. Even brief immersion at 13°C (55.4°F) feels frosty.

Daylight

In May, the average length of the day in Cardiff is 15h and 38min.
On the first day of the month, sunrise is at 5:43 am and sunset at 8:36 pm. On the last day of May, sunrise is at 5:01 am and sunset at 9:19 pm BST.

Sunshine

The month with the most sunshine is May, with an average of 8.2h of sunshine.

UV index

May through September, with an average maximum UV index of 4, are months with the highest UV index. A UV Index estimate of 3 to 5 represents a moderate threat to health from unsafe exposure to UV radiation for the ordinary person.
Note: In May, a regular UV index of 4 translates into these guidelines:
Undertake protective steps - Obligation to safeguard skin and eyes from harm is in place. Sun's radiation is most powerful around mid-day, so it's best to limit outdoor activities during this time. Sun protection is enhanced with clothing that boasts a tight weave yet offers a loose fit.

Frequently asked questions

What is the average May temperature in Cardiff?

In Cardiff, in May, the average high-temperature is 14.7°C (58.5°F), and the average low-temperature is 8.3°C (46.9°F).

What is the least humid month in Cardiff?

The months with the lowest humidity in Cardiff, United Kingdom, are April and May, with an average relative humidity of 81%.

What is the average humidity in May in Cardiff?

The average relative humidity in May is 81%.

How many days does it rain in May in Cardiff?

In May, in Cardiff, the rain falls for 10.3 days. Throughout May, 15mm (0.59") of precipitation is accumulated.

When it does not snow in Cardiff?

In Cardiff, United Kingdom, snow does not fall in March through October.

How cold is the water in May in Cardiff?

In May, the average sea temperature is 11.3°C (52.3°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.

What is the average length of the day in May in Cardiff?

The average day length in May is 15h and 38min.

When is the sunrise / sunset in May in Cardiff?

On the first day of May in Cardiff, United Kingdom, sunrise is at 5:43 am and sunset at 8:36 pm. On the last day of the month, sunrise is at 5:01 am and sunset at 9:19 pm BST.

What month has the most sunshine in Cardiff?

With an average of 8.2h of sunshine, May has the most sunshine of the year.

How long on average sun shines in May in Cardiff?

In May, the average sunshine duration in Cardiff is 8.2h.

When is the highest UV index in Cardiff?

The months with the highest UV index in Cardiff are May through September, with an average maximum UV index of 4.

How high is the UV index in May in Cardiff?

In Cardiff, United Kingdom, the average daily maximum UV index in May is 4. A UV Index reading of 3 to 5 represents a medium health risk from exposure to the Sun's UV radiation.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in May
Cardiff, United Kingdom

Average temperature in May - Cardiff, United Kingdom
  • Average high temperature in May: 14.7°C

The warmest month (with the highest average high temperature) is July (19°C).
The month with the lowest average high temperature is January (7.5°C).

  • Average low temperature in May: 8.3°C

The month with the highest average low temperature is August (13.3°C).
The coldest month (with the lowest average low temperature) is February (3.9°C).

Average pressure in May
Cardiff, United Kingdom

Average pressure in May - Cardiff, United Kingdom
  • Average pressure in May: 1016.7mbar

The month with the highest atmospheric pressure is September (1016.8mbar).
The month with the lowest atmospheric pressure is November (1010mbar).

Average wind speed in May
Cardiff, United Kingdom

Average wind speed in May - Cardiff, United Kingdom
  • Average wind speed in May: 15.9km/h

The windiest month (with the highest average wind speed) is February (22.3km/h).
The calmest months (with the lowest average wind speed) are June and July (15.2km/h).

Average humidity in May
Cardiff, United Kingdom

Average humidity in May - Cardiff, United Kingdom
  • Average humidity in May: 81%

The months with the highest relative humidity are November and December (86%).
The months with the lowest relative humidity are April and May (81%).

Average rainfall in May
Cardiff, United Kingdom

Average rainfall in May - Cardiff, United Kingdom
  • Average rainfall in May: 15mm

The wettest months (with the highest rainfall) are August and November (31mm).
The driest month (with the least rainfall) is April (12mm).

Average rainfall days in May
Cardiff, United Kingdom

Average rainfall days in May - Cardiff, United Kingdom
  • Average rainfall days in May: 10.3 days

The month with the highest number of rainy days is November (13.5 days).
The months with the least rainy days are February and April (9.1 days).

Average snowfall in May
Cardiff, United Kingdom

Average snowfall in May - Cardiff, United Kingdom
  • Average snowfall in May: 0mm

The month with the highest snowfall is February (5mm).
The months with the least snowfall are March, April, May, June, July, August, September and October (0mm).

Average snowfall days in May
Cardiff, United Kingdom

Average snowfall days in May - Cardiff, United Kingdom
  • Average snowfall days in May: 0 days

The month with the highest number of snowfall days is February (1 days).
The months with the least snowfall days are April, May, June, July, August, September and October (0 days).

Average sea temperature in May
Cardiff, United Kingdom

Average sea temperature in May - Cardiff, United Kingdom
  • Average sea temperature in May: 11.3°C

The best months for swimming (with the highest average sea temperature) are August and September (16.6°C).
The coldest month (with the lowest average sea temperature) is March (8.7°C).

Average daylight in May /
Average sunshine in May
Cardiff, United Kingdom

Average daylight in May / Average sunshine in May - Cardiff, United Kingdom
  • Average daylight in May: 15h and 4min

The month with the longest days is June (Average daylight: 16h and 36min).
The month with the shortest days is December (Average daylight: 7h and 54min).

  • Average sunshine in May: 8h and 1min

The month with the most sunshine is May (Average sunshine: 8h and 12min).
The month with the least sunshine is November (Average sunshine: 3h and 54min).

Average sunshine days in May
Cardiff, United Kingdom

Average sunshine days in May - Cardiff, United Kingdom
  • Average sunshine days in May: 18.4 days

The month with the most sunshine days is April (19.2 days).
The month with the least sunshine days is November (13.7 days).

Average UV index in May
Cardiff, United Kingdom

Average UV index in May - Cardiff, United Kingdom
  • Average UV index in May: 4

The months with the highest UV index are May, June, July, August and September (UV index 4).
The months with the lowest UV index are January, February, March, November and December (UV index 2).

Average cloud cover in May
Cardiff, United Kingdom

Average cloud cover in May - Cardiff, United Kingdom
  • Average cloud cover in May: 46

The month with the most cloud cover is November (Cloud cover 61).
The months with the least cloud cover are April and May (Cloud cover 46).

Average visibility in May
Cardiff, United Kingdom

Average visibility in May - Cardiff, United Kingdom
  • Average visibility in May: 9km

The months with the highest visibility are February, March and December (10km).
The months with the lowest visibility are January, April, May, June, July, August, September, October and November (9km).

Cardiff, United Kingdom

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