May Weather in Belfast, United Kingdom

Last updated: March 17, 2025

May in Belfast, United Kingdom showcases a vibrant transition into warmer weather, with temperatures peaking at a delightful 22°C (71°F) and averaging around 11°C (52°F). While the month brings an awakening of nature, it also experiences its share of precipitation, totaling about 66 mm (2.6 in) over 13 days, resulting in a humid environment with an average humidity level of 82%. Whether you're wandering through lush gardens or exploring the city's rich history, be prepared for the occasional shower as the city embraces the beauty of spring.

May Temperature in Belfast

In May, Belfast begins to shake off the lingering chill of winter, welcoming milder temperatures that signal the onset of spring. With a minimum of 1°C (34°F) and an average temperature rising to 11°C (52°F), the city experiences a pleasant warming trend. Daytime highs can reach up to 22°C (71°F), making this month ideal for outdoor exploration. The transition from April's coolness is evident as the higher temperatures in May set the stage for the forthcoming summer months. This gradual increase not only enhances the vibrancy of the city's parks and gardens but also invites locals and visitors alike to enjoy Belfast's lively atmosphere as it basks in more favorable weather conditions.

May Weather in Belfast: Daily Temperature Highs, Lows, and Averages

The chart illustrates May temperature patterns in Belfast, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends.
JanFebMarAprMayJunJulAugSepOctNovDec424344475257605956514744
Data source: Temperature data for Belfast generated using information from the Copernicus Climate Change Service.
Choose your preferred temperature unit
The average of daily temperatures (24 hours) calculated across all days in the month.

May Precipitation in Belfast

In May, Belfast experiences a moderate increase in precipitation, with an average total of 66 mm (2.6 in) spread over 13 days. This marks a notable rise from the drier April, which saw only 45 mm of rain. As spring unfolds, May’s rainfall prepares the city for the lushness of summer, although it remains less wet than the subsequent months of June and August. Interestingly, February and November are the wettest months, underscoring a trend of higher precipitation earlier and later in the year. The variability in May’s rainfall reflects the unpredictable nature of the British weather, balancing between the freshness of spring and the onset of summer.

May Precipitation Trends in Belfast

The chart displays monthly precipitation patterns in Belfast, with values for each month alongside May's data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how May's conditions compare to those of other months.
JanFebMarAprMayJunJulAugSepOctNovDec6089804566788411575929491
Data source: Precipitation data for May generated using information from the Copernicus Climate Change Service.
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May Humidity in Belfast

As the calendar turns to May, Belfast experiences a slight dip in humidity, with levels around 82%. This marks a noticeable decrease from the preceding months, providing a breath of fresh air after the wetter spring. Humidity remains relatively high throughout the year, peaking in the colder months of November and December at 90%, which adds to the city's lush, green landscape. The trend suggests a gradual easing of moisture as summer approaches, with June's humidity climbing back up to 84%. Overall, Belfast's May signifies a brief reprieve before the typical moist, temperate climate returns, making it a delightful transition into late spring.

May Average Humidity in Belfast

This chart illustrates the average monthly humidity levels in Belfast, with May's data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, allowing you to see how May's humidity levels compare to other months.
JanFebMarAprMayJunJulAugSepOctNovDec87%86%86%85%82%84%86%86%88%89%90%87%
Data source: Humidity data for May generated using information from the Copernicus Climate Change Service.

May UV Index in Belfast

As May arrives in Belfast, residents experience a noticeable shift in sun exposure, with the UV Index climbing to 7, signaling a high exposure category and a reduced burn time of just 25 minutes. This is a significant increase from the preceding months, highlighting the approaching summer season. In April, the UV Index reached only 5, which was classified as moderate, allowing for longer sun exposure without the risk of sunburn. Such trends suggest that as the year progresses, UV radiation intensifies, urging everyone to stay vigilant and protected against harmful rays in May and beyond. For detailed information on the UV Index throughout the year, visit Belfast UV Index.

Maximum UV Index Levels in Belfast for May

The chart shows the monthly maximum UV Index (UVI) for Belfast in May, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues.
JanFebMarAprMayJunJulAugSepOctNovDec124578865321
Data source: Belfast May UVI data generated using information from the Copernicus Climate Change Service.

UV Risk Categories

  •  Extreme (11+): Avoid the sun, stay in shade.
  •  Very High (8-10): Limit sun exposure.
  •  High (6-7): Use SPF 30+ and protective clothing.
  •  Moderate (3-5): Midday shade recommended.
  •  Low (0-2): No protection needed.

May Sunshine in Belfast

As spring transitions into summer, May shines brilliantly in Belfast, bringing an impressive 403 hours of sunshine—the highest total for the year. This radiant month follows a steady ascent from January's mere 81 hours, showcasing a remarkable surge in daylight as the days lengthen. April’s 322 hours set the stage for this sunny climax, while the months that follow, including June and July, still bask in generous light, albeit slightly less than May. The gradual decline in sunshine hours beginning in August serves as a gentle reminder that while the warmth of summer lingers, the cooler months of autumn are just around the corner. Overall, May stands out as a vibrant peak in Belfast's annual sunshine journey, inviting locals and visitors alike to revel in the enchanting glow of spring.

Monthly Sunshine Duration in Belfast: May Highlighted

The May sunshine duration represents the total number of hours Belfast experiences direct sunlight during the month of May, excluding cloudy or obstructed periods. This chart compares the sunshine duration of May with the other months of the year.
JanFebMarAprMayJunJulAugSepOctNovDec81h150h209h322h403h394h399h349h295h232h115h87h
Data source: Belfast May Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Belfast During May

In Belfast, May brings a refreshing shift in weather, offering a 33% chance of sunny days that stand out amidst the cooler months. Following the brighter spell of April at 42%, May’s likelihood of sunshine suggests a gradual transition towards the summer, though it remains lower than earlier spring days. This upward trend from April gives hope for delightful afternoons, especially when juxtaposed with the lower percentages found in the colder months. As summer approaches, while June dips back to 23%, it’s clear that May is a key moment in the quest for sunnier skies in this charming city.

Percentage of Sunny Days in May in Belfast

The chart illustrates the percentage of sunny days in Belfast throughout the year, with May highlighted. It highlights the variation in sunshine across each month and provides an overview of the typical frequency of sunny days, offering insights into how often Belfast experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec27%23%20%42%33%23%30%21%20%18%20%14%
Data source: Belfast May chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Belfast in May

As spring transitions into summer, May in Belfast shines with an impressive 16 hours of daylight, marking a significant increase from the 14 hours in April. This upward trend continues into June, which boasts the longest days of the year at 17 hours. The gradual lengthening of daylight from January's modest 7 hours creates a welcoming atmosphere, encouraging outdoor activities and social gatherings. As the year progresses towards autumn, daylight begins to wane, dropping to 12 hours in September and further declining to 10 hours by October. However, the vibrant burst of light in May not only heralds the arrival of summer but also ignites a spirited anticipation for the warm days ahead.

Average Daylight Hours in Belfast for May

The chart illustrates the variation in daylight duration in Belfast throughout the year, with May highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec7h 56m9h 44m11h 54m14h 7m16h 5m17h 7m16h 34m14h 47m12h 38m10h 26m8h 27m7h 21m
Data source: Belfast daylight hours, calculated by summing the hours between sunrise and sunset for each day.

May Winds in Belfast

In May, Belfast experiences a gentle average wind speed of 3.9 m/s (9 mph), which is a slight uptick from the calmness of April. This month marks a transition as the wind begins to pick up again after a series of relatively low readings in the spring months. Interestingly, while March had a higher average of 4.8 m/s (11 mph), May’s breezes offer a refreshing yet mild experience, perfect for outdoor activities. As the city approaches the summer, the winds remain relatively soft, with only a modest decline heading into June. Throughout the year, Belfast sees a notable fluctuation in wind speeds, with January and November showcasing the most robust gusts. Overall, May’s winds provide a delightful blend of warmth and movement, inviting residents and visitors to enjoy the blooming surroundings.

Average May Wind Speed in Belfast

The chart displays monthly wind speed patterns in Belfast, with values for each month shown alongside May's data, which is highlighted for easy comparison. It illustrates the average wind speed, offering insights into how May's wind conditions compare to the rest of the year.
JanFebMarAprMayJunJulAugSepOctNovDec4.36.24.83.53.9 m/s3.82.63.23.44.75.04.9
Data source: Belfast May wind data, generated using information from the Copernicus Climate Change Service.

How May Weather in Belfast Compares to Other Months

The weather in Belfast changes throughout the year, offering a unique experience in each season. Below is a month-by-month comparison of May's weather with other months, highlighting differences in temperature, precipitation, and other key factors. Click on each section to discover seasonal trends in Belfast and find detailed weather information for every month.

May and January present contrasting weather patterns. In May, temperatures range from a cool 1°C (34°F) at night to a pleasant 22°C (71°F) during the day, with an average of 11°C (52°F). It is generally wetter, with 66 mm (2.6 in) of precipitation spread over 13 days and a humidity level of 82%. Conversely, January records colder temperatures, dipping as low as -4°C (26°F) and peaking at 14°C (57°F), with an average of 6°C (43°F). Precipitation in January is slightly lower at 60 mm (2.3 in) over 10 days, accompanied by higher humidity at 87%. For more detailed insights, check out Belfast weather in January.

When comparing the weather in May and February, May typically exhibits much milder temperatures, with an average of 11°C (52°F) compared to February's cooler average of 6°C (43°F). May welcomes warmer conditions, peaking at 22°C (71°F), while February's maximum only reaches 13°C (56°F). Precipitation is slightly lower in May, with 66 mm (2.6 in) over 13 days, versus February’s 89 mm (3.5 in) across 14 days. Additionally, May experiences slightly lower humidity at 82%, compared to February's 86%. For more details, you can visit Belfast weather in February.

When comparing the weather in March and May, May generally offers milder temperatures, with a minimum of 1°C (34°F) and an average of 11°C (52°F) rising to a maximum of 22°C (71°F). In contrast, March is cooler, starting at a minimum of -3°C (27°F) and averaging 7°C (44°F), with a maximum of just 16°C (60°F). Precipitation levels are also notable; March experiences slightly more rain, with 80 mm (3.2 in) over 16 days, while May sees 66 mm (2.6 in) spread across 13 days. Additionally, May's relative humidity is slightly lower at 82% compared to March's 86%, making it feel a bit drier. For more detailed insights, you can explore Belfast weather in March.

In comparing the weather of May and April, May tends to be warmer and wetter than its predecessor. The average temperature in May is 11°C (52°F), significantly higher than April's average of 8°C (47°F), with May reaching maximum temperatures of 22°C (71°F) compared to April's high of 18°C (65°F). Additionally, May experiences a bit more precipitation at 66 mm (2.6 in) over 13 days, while April sees 45 mm (1.8 in) across 10 days. Humidity levels are slightly lower in May at 82%, compared to April's 85%. For more detailed weather patterns, check out Belfast weather in April.

May and June exhibit notable differences in weather patterns. In May, temperatures range from a chilly minimum of 1°C (34°F) to a pleasant maximum of 22°C (71°F), with an average temperature of 11°C (52°F). This month sees about 66 mm (2.6 in) of precipitation over 13 days, accompanied by a humidity level of 82%. In contrast, June brings warmer temperatures, with a minimum of 6°C (43°F), an average of 14°C (57°F), and a maximum of 26°C (79°F). However, June also witnesses an increase in precipitation to 78 mm (3.1 in) across 14 days, along with a slight rise in humidity to 84%. For a more detailed overview, check out Belfast weather in June.

In May, the weather tends to be cooler, with temperatures ranging from a minimum of 1°C (34°F) to a maximum of 22°C (71°F), and an average temperature of 11°C (52°F). The month sees about 66 mm (2.6 in) of precipitation over approximately 13 days, accompanied by a humidity level of 82%. In contrast, July experiences warmer temperatures, with a minimum of 8°C (47°F) and a maximum of 26°C (78°F), averaging 15°C (60°F). However, rainfall increases slightly to 84 mm (3.3 in) over 14 days, and humidity rises to 86%. For more detailed information, check out the Belfast weather in July.

In May, temperatures in Belfast typically range from a chilly minimum of 1°C (34°F) to a pleasant maximum of 22°C (71°F), with an average of 11°C (52°F). The month experiences about 66 mm (2.6 in) of precipitation over 13 days, accompanied by relatively high humidity levels of 82%. In contrast, August sees warmer temperatures, with a minimum of 8°C (46°F) and an average of 15°C (59°F), while still reaching a maximum of 22°C (71°F). However, August is wetter, with 115 mm (4.5 in) of precipitation over 19 days and a slight increase in humidity to 86%. For more detailed information, you can visit Belfast weather in August.

May and September present contrasting weather patterns, despite their similar maximum temperatures. In May, temperatures range from a cool 1°C (34°F) to an average of 11°C (52°F), with a maximum of 22°C (71°F). The month sees around 66 mm (2.6 in) of rainfall over 13 days, accompanied by a humidity level of 82%. September, on the other hand, experiences slightly warmer temperatures, with a minimum of 4°C (39°F) and an average of 13°C (56°F), while still reaching a maximum of 21°C (71°F). Precipitation increases to 75 mm (3.0 in) over 15 days, and humidity levels rise to 88%. For more detailed insights into September's climate, visit Belfast weather in September.

May and October both experience mild average temperatures, with May reaching a maximum of 22°C (71°F) compared to October's peak of 18°C (65°F). Both months share a similar minimum temperature of around 1°C (34°F). However, October tends to be wetter, receiving 92 mm (3.6 in) of precipitation over 15 days, while May sees slightly less at 66 mm (2.6 in) across 13 days. Additionally, October has higher humidity levels at 89%, compared to May's 82%. For more detailed information, check out the link: Belfast weather in October.

May and November exhibit distinct weather patterns, each characterized by their unique temperature ranges and precipitation levels. In May, temperatures can soar as high as 22°C (71°F), offering milder conditions with an average of 11°C (52°F) and only 66 mm (2.6 in) of precipitation over approximately 13 days. In contrast, November experiences cooler temperatures, peaking at just 15°C (59°F) and averaging 8°C (47°F). Additionally, November sees increased rainfall at 94 mm (3.7 in) over about 15 days, accompanied by higher humidity levels of 90%. For more information on November's weather, you can visit Belfast weather in November.

May and December present striking contrasts in weather. In May, temperatures generally range from a minimum of 1°C (34°F) to a maximum of 22°C (71°F), with an average of 11°C (52°F) and relatively moderate precipitation at 66 mm (2.6 in) over 13 days. This month enjoys a pleasant humidity level of 82%, making it feel quite comfortable for outdoor activities. In comparison, December experiences cooler temperatures, with a minimum of -1°C (30°F), an average of 6°C (44°F), and a maximum of 13°C (56°F). The month is also wetter, receiving 91 mm (3.6 in) of rain over 15 days, combined with slightly higher humidity at 86%. For more details on the specific weather conditions, you can check Belfast weather in December.

Compare Belfast's Climate with Cities Worldwide

Conclusion: What to Expect From May Weather in Belfast

May in Belfast marks a shift towards milder and more pleasant weather compared to the earlier months of the year. With average temperatures reaching a comfortable 11°C (52°F) and occasional peaks of up to 22°C (71°F), the month brings a welcome warmth as spring unfolds. However, it still retains a hint of the chill from winter, as minimum temperatures can drop to around 1°C (34°F). Rainfall persists, contributing to a total of 66 mm (2.6 in) over approximately 13 days, but the overall humidity remains high at 82%, creating an invigorating atmosphere. As such, May is a transitional month that beautifully balances the remnants of winter with the blossoming warmth of spring. For a deeper dive into the nuances of Belfast's climate, explore Belfast Climate.