May Weather in Half Moon Bay, United States

Last updated: February 24, 2025

In Half Moon Bay, United States, the weather in May presents a delightful blend of mild temperatures and refreshing coastal climes. With a maximum temperature of 21°C (69°F) and an average of 13°C (56°F), residents and visitors can enjoy the comfortable warmth interspersed with cool breezes. The month sees a minimum temperature of 9°C (48°F), ensuring chilly evenings. Precipitation is modest, accumulating 22 mm (0.9 in) over just 2 days, while humidity levels hover around 83%, adding a touch of freshness to the air. Overall, May offers a picturesque and invigorating atmosphere for outdoor activities along the stunning coastline.

May Temperature in Half Moon Bay

In May, Half Moon Bay begins to warm up as spring transitions into summer, showcasing a delightful rise in temperatures. The minimum temperature settles at 9°C (48°F), while the average climbs to 13°C (56°F), marking a noticeable increase from the cooler early months of the year. With a maximum temperature of 21°C (69°F), residents and visitors alike can enjoy more outdoor activities and bask in the pleasant sunshine. This month paints a clear picture of warming trends, as May is a bridge to the consistently warmer temperatures that arrive in June and beyond, while still retaining the coastal charm that makes Half Moon Bay unique.

May Weather in Half Moon Bay: Daily Temperature Highs, Lows, and Averages

The chart illustrates May temperature patterns in Half Moon Bay, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends.
JanFebMarAprMayJunJulAugSepOctNovDec525253545558586062595653
Data source: Temperature data for Half Moon Bay 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 Half Moon Bay

In Half Moon Bay, May typically marks the transition toward drier conditions, showcasing a significant decrease in precipitation compared to the earlier months. With just 22 mm (0.9 in) of rain falling over 2 days, May is a stark contrast to the wetter January and February, each averaging around 102 mm (4.0 in). As spring progresses, the community enjoys an abundance of sunshine, paving the way for outdoor activities with dramatically fewer rainy days. This trend continues into June, with only 4 mm (0.2 in) recorded, illustrating a clear shift towards the warm and dry summer months ahead. Overall, May sets the stage for the dry season, encouraging residents and visitors alike to embrace the pleasant coastal climate.

May Precipitation Trends in Half Moon Bay

The chart displays monthly precipitation patterns in Half Moon Bay, 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.
JanFebMarAprMayJunJulAugSepOctNovDec1021017834224333274892
Data source: Precipitation data for May generated using information from the Copernicus Climate Change Service.
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May Humidity in Half Moon Bay

In Half Moon Bay, May brings an average humidity of 83%, slightly higher than the preceding months of April. This increase aligns with the trend of fluctuating humidity levels throughout the year, showing a gradual rise as the warmer summer months approach. Notably, the humidity peaks in the summer, with July and August reaching 87%, emphasizing the coastal climate's tendency towards moisture as the season warms. Meanwhile, as fall rolls in, humidity levels begin to drop again, further underscoring the seasonal rhythm of this charming coastal town. Overall, May illustrates this transitional phase, where the lingering freshness of spring melds into the humid embrace of summer.

May Average Humidity in Half Moon Bay

This chart illustrates the average monthly humidity levels in Half Moon Bay, 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.
JanFebMarAprMayJunJulAugSepOctNovDec85%82%82%79%83%84%87%87%86%80%79%79%
Data source: Humidity data for May generated using information from the Copernicus Climate Change Service.

May UV Index in Half Moon Bay

As May rolls in, Half Moon Bay experiences a striking peak in its UV Index, hitting an impressive 10—classified as very high—with a burn time of just 15 minutes. This notable increase from the moderate levels seen in the earlier months signifies a shift towards a season demanding greater sun protection. April's UV Index of 9 and March's 8 mark a clear upward trend, culminating in May's intensity. Following May, June and July promise even more extreme conditions, with UV Index levels reaching 11. For those soaking up the sun, it's essential to stay vigilant as the rays become potent. To learn more, visit Half Moon Bay UV Index.

Maximum UV Index Levels in Half Moon Bay for May

The chart shows the monthly maximum UV Index (UVI) for Half Moon Bay 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.
JanFebMarAprMayJunJulAugSepOctNovDec3589101111109743
Data source: Half Moon Bay 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 Half Moon Bay

As spring transitions into summer, May shines brightly in Half Moon Bay, basking in an impressive 341 hours of sunshine. This surge in sunlight marks a significant increase from the preceding months, with April offering 296 hours, setting the stage for brighter days ahead. The trend continues as the days grow longer, with June boasting even more hours at 355. This upward trajectory not only enhances the area’s natural beauty but also invites locals and visitors alike to indulge in the outdoor activities that flourish during this sun-drenched period. The gradual increase in sunshine hours not only encapsulates the charm of May but also signals the vibrant summer season that follows.

Monthly Sunshine Duration in Half Moon Bay: May Highlighted

The May sunshine duration represents the total number of hours Half Moon Bay 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.
JanFebMarAprMayJunJulAugSepOctNovDec151h216h263h296h341h355h349h320h299h276h225h194h
Data source: Half Moon Bay May Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Half Moon Bay During May

In Half Moon Bay, the month of May emerges as a promising time for sun-seekers, boasting a 57% chance of sunny weather. This places it nicely in the middle of the spectrum when compared to the rest of the year. Following a sunny March, which enjoys the highest probability of clear skies at 60%, May experiences a slight dip but retains a favorable outlook. Interestingly, January kicks off the year with the lowest likelihood of sunshine at just 39%, while the summer months, particularly July, see a dramatic drop to 30%. Overall, the trend indicates that May is a sweet spot before the cooler months hit, offering a delightful blend of warmth while still competing well against its neighboring months.

Percentage of Sunny Days in May in Half Moon Bay

The chart illustrates the percentage of sunny days in Half Moon Bay 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 Half Moon Bay experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec39%56%60%44%57%45%30%43%47%50%43%35%
Data source: Half Moon Bay May chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Half Moon Bay in May

As spring unfolds in Half Moon Bay, May emerges as a beacon of daylight, boasting a generous 14 hours of sunlight. This pattern reflects a steady increase from January's somber 9 hours, with daylight gradually extending as the seasons shift. In April, residents enjoy a notable boost to 13 hours, creating a delightful transition into May. The long days of late spring signal a peak that holds firm into June and July, allowing for ample opportunities to savor outdoor activities. As summer wanes, daylight gradually recedes, with August clocking in at 13 hours, followed by a gentle decline through the fall months. Overall, May stands out as a highlight in the annual cycle, representing the height of daylight and the promise of vibrant summer days ahead.

Average Daylight Hours in Half Moon Bay for May

The chart illustrates the variation in daylight duration in Half Moon Bay throughout the year, with May highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec9h 54m10h 49m11h 59m13h 11m14h 11m14h 41m14h 25m13h 31m12h 22m11h 10m10h 8m9h 36m
Data source: Half Moon Bay daylight hours, calculated by summing the hours between sunrise and sunset for each day.

May Winds in Half Moon Bay

In May, Half Moon Bay experiences a refreshing uptick in wind speed, averaging 5.4 m/s (12 mph). This marks a notable increase from the preceding months, with April at 4.5 m/s (10 mph) and March slightly lower at 4.2 m/s (9 mph). As spring transitions towards summer, the wind begins to dance more energetically through the coastal landscape. Interestingly, this month's winds are the strongest before a gradual decline begins in June, where the average settles back to 4.3 m/s (10 mph). Overall, May serves as a pivotal moment in the season, characterized by these vibrant breezes that invigorate the coastal air, making it an ideal time for outdoor activities and seaside strolls.

Average May Wind Speed in Half Moon Bay

The chart displays monthly wind speed patterns in Half Moon Bay, 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.
JanFebMarAprMayJunJulAugSepOctNovDec3.54.34.24.55.4 m/s4.33.43.33.13.83.04.1
Data source: Half Moon Bay May wind data, generated using information from the Copernicus Climate Change Service.

How May Weather in Half Moon Bay Compares to Other Months

The weather in Half Moon Bay 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 Half Moon Bay and find detailed weather information for every month.

May and January present notable differences in weather patterns. In May, temperatures range from a minimum of 9°C (48°F) to a pleasant average of 13°C (56°F), peaking at 21°C (69°F). The month sees relatively low precipitation at 22 mm (0.9 in) over just 2 days, accompanied by a humidity level of 83%. In contrast, January experiences cooler temperatures, with a minimum of 5°C (41°F) and an average of 11°C (53°F), reaching up to 20°C (68°F). This month is significantly wetter, accumulating 102 mm (4.0 in) of rainfall over 9 days and maintaining a similar humidity level of 85%. For more detailed information, see Half Moon Bay weather in January.

In comparing the weather of May and February, May generally offers milder temperatures with a minimum of 9°C (48°F) and an average of 13°C (56°F), reaching a maximum of 21°C (69°F). In contrast, February's temperatures are slightly lower, with a minimum of 5°C (41°F) and an average of 11°C (53°F), but it can still peak at 20°C (69°F). While May enjoys relatively light precipitation of 22 mm (0.9 in) over just 2 days, February experiences significantly heavier rainfall, totaling 101 mm (4.0 in) across 9 days. Despite the slightly lower humidity in February at 82% compared to May's 83%, the weather tends to feel more damp due to the increased precipitation levels. For more details, you can check Half Moon Bay weather in February.

In comparing the weather of May and March, May tends to be slightly warmer, with average temperatures ranging from a minimum of 9°C (48°F) to a maximum of 21°C (69°F), while March has a lower average, with temperatures ranging from 7°C (44°F) to 19°C (67°F). Precipitation is significantly lower in May, with only 22 mm (0.9 in) over just 2 days, compared to March’s 77 mm (3.0 in) spread over 11 days. Humidity levels remain similar, with May at 83% and March at 82%. For further details, you can check Half Moon Bay weather in March.

In comparing the weather of May and April, May tends to be slightly warmer with average temperatures of 13°C (56°F) compared to April's 12°C (55°F). However, April features a higher maximum temperature of 25°C (78°F), while May's maximum is only 21°C (69°F). Precipitation also varies, with April receiving 34 mm (1.3 in) over 5 days, making it wetter than May, which has only 22 mm (0.9 in) across 2 days. Humidity levels are similar, with May at 83% and April at 79%. For more detailed information about April's weather, you can check Half Moon Bay weather in April.

In comparing the weather between May and June, June generally offers warmer temperatures. While May sees a minimum of 9°C (48°F) and a maximum of 21°C (69°F), June starts with a slightly higher minimum of 10°C (51°F) and reaches up to a maximum of 27°C (81°F). Additionally, June experiences significantly less precipitation, with only 4 mm (0.2 in) over zero rainy days, compared to May's 22 mm (0.9 in) over two days. Both months maintain high humidity levels, with May at 83% and June slightly higher at 84%. For a more detailed look at June weather, you can visit Half Moon Bay weather in June.

In comparing the weather between May and July, we see a subtle shift in temperatures and precipitation patterns. May features a broader temperature range with minimums around 9°C (48°F), averaging 13°C (56°F), and highs reaching 21°C (69°F). It also experiences more rain, with about 22 mm (0.9 in) falling over 2 days, resulting in a humidity level of 83%. By contrast, July presents slightly warmer minimum temperatures of 11°C (51°F) and an average of 15°C (59°F), but with a maximum temperature that remains similar at 20°C (69°F). Notably, July boasts a significantly drier climate, with just 3 mm (0.1 in) of precipitation over zero rainy days, leading to a higher humidity level of 87%. For those interested in the specifics, you can find more detailed information about Half Moon Bay weather in July.

May and August offer distinct weather experiences. In May, temperatures range from a minimum of 9°C (48°F) to a maximum of 21°C (69°F), with an average of 13°C (56°F). The month sees about 22 mm (0.9 in) of precipitation over two days, and humidity hovers around 83%. In contrast, August tends to be warmer, with temperatures ranging from a minimum of 11°C (53°F) to a maximum of 24°C (76°F), averaging 16°C (61°F). Precipitation is minimal in August, only 3 mm (0.1 in) on no days, and humidity is slightly higher at 87%. For more specific details on August weather in Half Moon Bay, you can visit Half Moon Bay weather in August.

May and September showcase distinct weather patterns, with May generally being cooler and more humid. In May, temperatures range from a chilly 9°C (48°F) at night to a comfortable 21°C (69°F) during the day, accompanied by about 22 mm (0.9 in) of rain that typically falls over two days. In contrast, September experiences milder conditions, with minimum temperatures of 11°C (52°F) and maximums reaching a warm 31°C (88°F). Notably, September sees very little rainfall, averaging just 3 mm (0.1 in) with no rainy days, and a slightly higher humidity level of 86%. For more information on September weather specifically in Half Moon Bay, you can visit Half Moon Bay weather in September.

May and October present a lovely transition in weather, each with its distinctive characteristics. In May, temperatures range from a low of 9°C (48°F) to a comfortable high of 21°C (69°F), with an average temperature around 13°C (56°F). The month sees modest rainfall, totaling 22 mm (0.9 in) over just two days, and maintains a relatively high humidity level of 83%.

In contrast, October tends to be warmer, with minimum temperatures similar at 9°C (49°F) but reaching a maximum of 27°C (80°F), and an average around 15°C (60°F). Although slightly wetter with 27 mm (1.1 in) of precipitation over two days, the humidity is slightly lower at 80%.

For more insights into October's weather patterns, check out Half Moon Bay weather in October.

In comparing the weather in May and November, both months share a similar average temperature of 13°C (56°F), with maximum temperatures reaching 21°C (69°F) in May and 21°C (70°F) in November. However, November is slightly cooler in the early mornings, with minimum temperatures of 7°C (45°F) compared to May's 9°C (48°F). Rainfall is more prevalent in November, with 48 mm (1.9 in) of precipitation over five days, significantly higher than May's 22 mm (0.9 in) over just two days. The humidity levels remain relatively close, with May at 83% and November at 79%. For more specific details about the weather conditions, you can check Half Moon Bay weather in November.

May and December present contrasting weather patterns. In May, temperatures range from a minimum of 9°C (48°F) to a maximum of 21°C (69°F), with an average temperature of 13°C (56°F). The month sees relatively low precipitation, totaling 22 mm (0.9 in) over just 2 days, and humidity levels are high at 83%. In contrast, December experiences cooler temperatures, with a minimum of 6°C (44°F) and a maximum of 19°C (67°F), averaging at 12°C (53°F). This month is much wetter, with precipitation reaching 92 mm (3.6 in) across 10 days, and humidity drops slightly to 79%. For more details on the December climate, check out Half Moon Bay weather in December.

Compare Half Moon Bay's Climate with Cities Worldwide

Conclusion: What to Expect From May Weather in Half Moon Bay

As May rolls in, Half Moon Bay experiences a delightful transition characterized by mild temperatures and increasing humidity. Unlike the cooler months that precede it, May offers a pleasant average of 13°C, making outdoor activities more enjoyable. With only a couple of days of precipitation, this month typically sees more sunshine, which contrasts sharply with the rainier periods earlier in the year. The moderate climate and relatively low rainfall make May an ideal time for visitors to savor the beauty of coastal landscapes. Explore more about the delightful weather patterns throughout the year at Half Moon Bay Climate.