May Weather in Seattle, United States

Last updated: February 24, 2025

In Seattle, May ushers in the transition to warmer days, showcasing a maximum temperature of 28°C (82°F), while the average hovers around a comfortable 14°C (57°F). As the city shakes off the cooler months, it experiences a minimum temperature of 5°C (42°F), inviting outdoor adventures. Despite the pleasant warmth, precipitation remains notable, with 68 mm (2.7 in) spread across 12 rain-soaked days, contributing to the city's iconic lush greenery. With humidity levels at a muggy 81%, May in Seattle embraces the beauty of spring while reminding residents to keep an umbrella handy!

May Temperature in Seattle

In May, Seattle begins to shed its wintry chill, with temperatures indicating a significant transition towards warmer days. The minimum temperature creeps up to 5°C (42°F), while the average soars to 14°C (57°F), establishing a comfortable environment for outdoor activities. On particularly bright days, highs can reach as much as 28°C (82°F), signaling the approach of summer. This pattern reflects a broader trend in the Pacific Northwest, where spring rains gradually give way to longer daylight hours and more pleasant weather, inviting residents and visitors alike to enjoy the city’s vibrant parks and waterfronts. As Seattle warms up in May, it sets the stage for the sun-soaked months ahead, making it an ideal time to explore the city’s natural beauty.

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

The chart illustrates May temperature patterns in Seattle, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends.
JanFebMarAprMayJunJulAugSepOctNovDec424145505762666762524742
Data source: Temperature data for Seattle generated using information from the Copernicus Climate Change Service.
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The average of daily temperatures (24 hours) calculated across all days in the month.

May Precipitation in Seattle

In May, Seattle experiences a noticeable shift in its precipitation patterns, as the city enjoys 68 mm (2.7 in) of rain over 12 days. This marks a significant decline from the heavier rainfall of earlier months, like January and February, which see over 175 mm (6.9 in) of precipitation. As spring transitions into summer, May's milder conditions offer a refreshing break from the relatively wetter months, with fewer rainy days compared to April's 14. This trend continues into June, where rainfall decreases further to 63 mm (2.5 in) and 9 days of precipitation, heralding the drier summer season ahead. Overall, May serves as a bridge, capturing the essence of Seattle's unique climate with its blend of greenery and emerging sunny days.

May Precipitation Trends in Seattle

The chart displays monthly precipitation patterns in Seattle, 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.
JanFebMarAprMayJunJulAugSepOctNovDec17517712611768631916100155181196
Data source: Precipitation data for May generated using information from the Copernicus Climate Change Service.
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May Humidity in Seattle

In May, Seattle begins to enjoy a slight respite from the higher humidity levels of the earlier months, settling at 81%. This marks a transition toward drier conditions as the city moves into summer, evidenced by the gradual decrease from an elevated 87% in March and 84% in April. As June follows with just a slight increase to 82%, the trend indicates that while humidity remains relatively high compared to other parts of the country, Seattle experiences a noteworthy decline as summer approaches, with July further dropping to 79%. This pattern not only highlights the city's unique climate but also provides a refreshing shift, inviting residents and visitors to enjoy the mild, pleasant May weather.

May Average Humidity in Seattle

This chart illustrates the average monthly humidity levels in Seattle, 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.
JanFebMarAprMayJunJulAugSepOctNovDec86%86%87%84%81%82%79%63%62%83%89%88%
Data source: Humidity data for May generated using information from the Copernicus Climate Change Service.

May UV Index in Seattle

As May arrives in Seattle, the UV Index escalates to 8, marking the start of a distinctly very high exposure category that demands attention. With a burn time of just 15 minutes, it's crucial for residents and visitors to take precautions against harmful UV rays. This sharp increase from April's UV Index of 6 signals a trend toward more intense sun exposure as summer approaches, continuing through to June and July. Those enjoying the increasing warmth should be mindful of sun safety practices, especially with the index expected to remain high. For more information on UV trends and how to protect yourself, check out Seattle UV Index.

Maximum UV Index Levels in Seattle for May

The chart shows the monthly maximum UV Index (UVI) for Seattle 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.
JanFebMarAprMayJunJulAugSepOctNovDec235689987521
Data source: Seattle 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 Seattle

As spring blossoms into summer, May in Seattle shines with an impressive 299 sunshine hours, marking a delightful peak in the region's brightness. This month exhibits a steady rise from the earlier 80 hours in January to 229 hours in April, embodying a clear trend of increasing daylight that enhances the vibrant atmosphere of the city. Following May, June continues the upward trajectory with 311 hours, showcasing the anticipation of summer days ahead. The gradual buildup of sunshine not only rejuvenates the landscape but also uplifts the spirits of Seattleites, celebrating the end of winter’s gray and welcoming the warmth of sunlit adventures.

Monthly Sunshine Duration in Seattle: May Highlighted

The May sunshine duration represents the total number of hours Seattle 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.
JanFebMarAprMayJunJulAugSepOctNovDec80h123h199h229h299h311h361h330h254h190h114h93h
Data source: Seattle May Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Seattle During May

In May, Seattle experiences a moderate likelihood of sunny weather, with a 37% chance of sunshine. This marks a significant shift from the earlier months, as the city transitions from the gloomy days of winter, where chances hover around 16% in January and 17% in February, to a more promising 50% in April. Though the sun may not fully break through the clouds just yet, May shows signs of spring's arrival—set against a backdrop of increasing sunny days that continues into the summer, where June sees a 58% chance and July peaks at 63%. Overall, while May's weather may still retain a bit of a cool, overcast character, the trend indicates a warming optimism as the season progresses, inviting residents to embrace the vibrant, blossoming beauty of the Pacific Northwest.

Percentage of Sunny Days in May in Seattle

The chart illustrates the percentage of sunny days in Seattle 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 Seattle experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec16%17%30%50%38%59%63%49%36%25%15%12%
Data source: Seattle May chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Seattle in May

As spring blossoms into summer, Seattle experiences a remarkable increase in daylight duration, with May boasting an impressive 15 hours of daylight. This month marks a significant transition from the shorter, darker days of winter, where January sees only 8 hours of sunlight. Following April's 13 hours, May's bright skies herald the beginning of consistently long days, which continue into June and July. As we journey into late summer, daylight starts to wane, tapering to 14 hours in August and gradually descending to 12 hours by September. This natural rhythm captures the essence of Seattle's seasons, where the extended daylight of spring and early summer invigorates both the city and its residents.

Average Daylight Hours in Seattle for May

The chart illustrates the variation in daylight duration in Seattle throughout the year, with May highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec8h 56m10h 16m11h 57m13h 40m15h 8m15h 52m15h 27m14h 8m12h 29m10h 47m9h 17m8h 30m
Data source: Seattle daylight hours, calculated by summing the hours between sunrise and sunset for each day.

May Winds in Seattle

May in Seattle ushers in a gentle breeze with an average wind speed of 2.5 m/s (6 mph), mirroring the calm conditions of March and April. As the city transitions from the chill of spring, the wind remains relatively mild, setting a serene backdrop for outdoor activities and blossoming nature. Notably, this is part of a trend where wind speeds dip to their lowest in the summer months, with July recording just 1.9 m/s (4 mph). Following May, the winds gradually pick up again, particularly in the fall, highlighting Seattle's dynamic climate that dances between calm and spirited as the seasons change. Overall, May's breezy yet soothing conditions make it a perfect time to embrace the beauty of Seattle's outdoors, with a refreshing whisper of wind that invites exploration.

Average May Wind Speed in Seattle

The chart displays monthly wind speed patterns in Seattle, 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.
JanFebMarAprMayJunJulAugSepOctNovDec2.83.42.52.42.5 m/s2.41.92.42.52.93.53.4
Data source: Seattle May wind data, generated using information from the Copernicus Climate Change Service.

How May Weather in Seattle Compares to Other Months

The weather in Seattle 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 Seattle and find detailed weather information for every month.

May and January present starkly contrasting weather conditions. In May, temperatures range from a mild 5°C (42°F) to a warm 28°C (82°F), with an average of 14°C (57°F). Precipitation is moderate at 68 mm (2.7 in) over about 12 days, and humidity sits at 81%. In contrast, January brings much colder temperatures, with a minimum of -7°C (19°F), an average of 6°C (43°F), and a maximum of just 14°C (57°F). It is also significantly wetter, receiving 175 mm (6.9 in) of precipitation across 16 days, along with a slightly higher humidity level of 86%. For a closer look at the winter climate, check out Seattle weather in January.

May and February exhibit striking contrasts in weather patterns. While February temperatures can plummet to a minimum of -10°C (14°F) and average just 5°C (41°F), May enjoys much milder conditions, with temperatures ranging from a minimum of 5°C (42°F) to a comfortable average of 14°C (57°F) and reaching a maximum of 28°C (82°F). Precipitation is also notably different; February sees a substantial 177 mm (7.0 in) of rain over 19 days, compared to May's lighter 68 mm (2.7 in) over just 12 days. Additionally, February's humidity sits at 86%, slightly higher than May's 81%, reinforcing the chilly and damp nature of winter months in contrast to the more pleasant spring atmosphere. For more details on February weather in Seattle, visit Seattle weather in February.

In comparing the weather of March and May, it's evident that May experiences milder temperatures, with a minimum of 5°C (42°F) and an average of 14°C (57°F), reaching up to 28°C (82°F). In contrast, March starts colder, with temperatures ranging from a minimum of -1°C (31°F) to an average of 7°C (46°F) and a maximum of 22°C (72°F). Despite the warmer conditions in May, it also sees slightly less precipitation, totaling 68 mm (2.7 in) over 12 days, compared to March's higher precipitation of 126 mm (4.9 in) over 17 days. Moreover, humidity levels are similar, with May at 81% and March slightly higher at 87%. For more detailed insights into March weather, check Seattle weather in March.

In comparing the weather of April and May, we can see a noticeable shift. May experiences a more favorable temperature range, with minimums around 5°C (42°F) and maximums reaching up to 28°C (82°F), while April has cooler highs of 24°C (75°F) and lows down to 1°C (34°F). Additionally, May boasts a lower average precipitation of 68 mm (2.7 in) over 12 days, compared to April's 117 mm (4.6 in) spread across 14 days. Humidity levels remain relatively similar, with May at 81% and April slightly higher at 84%. For a deeper look at April's climate specifics, check out Seattle weather in April.

May and June exhibit notable differences in weather patterns. In May, temperatures range from a minimum of 5°C (42°F) to a maximum of 28°C (82°F), with an average of 14°C (57°F). The month experiences 68 mm (2.7 in) of precipitation over 12 days, alongside a humidity level of 81%. In contrast, June sees increased warmth, with temperatures ranging from a minimum of 8°C (46°F) to a scorching maximum of 38°C (101°F), and an average temperature of 17°C (62°F). Precipitation slightly decreases to 63 mm (2.5 in) over 9 days, while humidity remains consistent at around 82%. For a more detailed look at June's weather, check out Seattle weather in June.

May and July present notably different weather patterns. In May, temperatures range from a chilly 5°C (42°F) to a pleasant 28°C (82°F), with an average of 14°C (57°F). The month sees 68 mm (2.7 in) of precipitation over 12 days, resulting in higher humidity at 81%. In contrast, July enjoys warmer conditions, with minimum temperatures of 11°C (52°F), an average of 19°C (67°F), and maximums reaching 32°C (91°F). Rainfall drops significantly to just 18 mm (0.7 in) over 5 days, and humidity slightly decreases to 79%. For more detailed insights, check out Seattle weather in July.

May and August present distinct contrasts in weather patterns. In May, temperatures range from a minimum of 5°C (42°F) to a maximum of 28°C (82°F), with an average of 14°C (57°F). The month sees considerable precipitation, totaling 68 mm (2.7 in) over about 12 days, and enjoys high humidity at 81%. In contrast, August boasts warmer temperatures, with a minimum of 10°C (51°F) and a maximum reaching 33°C (93°F), averaging 19°C (67°F). The month is significantly drier, with only 16 mm (0.6 in) of precipitation spread over just 5 days, and lower humidity at 63%. This makes August much more favorable for outdoor activities. For more insights into August weather, check out Seattle weather in August.

May and September both offer mild temperatures, but there are notable differences in their weather characteristics. In May, temperatures range from a minimum of 5°C (42°F) to a maximum of 28°C (82°F), with an average of 14°C (57°F) and significant humidity at 81%. This month typically experiences around 68 mm (2.7 in) of precipitation over about 12 days, contributing to a fresh and somewhat damp atmosphere.

In contrast, September shows a slight warming trend, with minimum temperatures of 8°C (46°F) and maximums reaching 30°C (86°F), averaging 16°C (62°F). However, it also sees increased precipitation, totaling about 100 mm (3.9 in) over 12 days, though humidity drops to a more comfortable 62%. For more detailed information on September's weather, visit Seattle weather in September.

May and October present contrasting weather conditions. In May, temperatures range from a minimum of 5°C (42°F) to a maximum of 28°C (82°F), with an average of 14°C (57°F). The month sees about 68 mm (2.7 in) of precipitation over 12 days, accompanied by a humidity level of 81%. In contrast, October experiences cooler temperatures, with a minimum of -1°C (30°F) and a maximum of 23°C (74°F), averaging 11°C (52°F). Precipitation significantly increases to 155 mm (6.1 in) over 15 days, and humidity rises slightly to 83%. For more details on the climate, you can check Seattle weather in October.

May and November present contrasting weather patterns. In May, temperatures rise from a chilly 5°C (42°F) at night to a comfortable 28°C (82°F) during the day, with an average of 14°C (57°F). The month sees moderate precipitation of 68 mm (2.7 in) over approximately 12 days, accompanied by relatively high humidity at 81%. Conversely, November experiences much cooler temperatures, ranging from a low of -1°C (30°F) to a high of 17°C (63°F) and an average of 8°C (47°F). It is also much wetter, with 181 mm (7.1 in) of rainfall over 18 days, and humidity increases to 89%. For more information, you can check Seattle weather in November.

May and December present stark contrasts in weather patterns. In May, temperatures range from a cool 5°C (42°F) to a warm 28°C (82°F), with an average of 14°C (57°F), while December sees much lower temperatures, with a minimum of -7°C (20°F) and a maximum of just 14°C (58°F), averaging around 6°C (42°F). Precipitation is also markedly different; May receives 68 mm (2.7 in) over 12 days, whereas December gets significantly wetter with 196 mm (7.7 in) spread over 19 days. The humidity levels remain elevated in both months, with December being slightly higher at 88% compared to May's 81%. For more details about Seattle's December weather, you can visit Seattle weather in December.

Compare Seattle's Climate with Cities Worldwide

Conclusion: What to Expect From May Weather in Seattle

As May unfolds in Seattle, the weather begins to shed its wintry chill, offering a delightful transition into warmer days. Temperatures rise, reaching a pleasant average of 14°C, making outdoor activities more enjoyable compared to the cooler months preceding it. However, don’t forget your umbrella; May is marked by 68 mm of precipitation over roughly 12 days, contributing to the region's signature lush, green landscapes. The 81% humidity adds a touch of warmth, creating a distinct character that sets May apart from Seattle's other months. For a deeper dive into the city's climate, explore Seattle Climate.