April Weather in Half Moon Bay, United States

Last updated: February 24, 2025

April in Half Moon Bay, United States, ushers in a mild climate characterized by a maximum temperature of 25°C (78°F) and an average temperature of 12°C (55°F). The season brings refreshing breezes, with nighttime lows dipping to a minimum of 7°C (45°F). While residents and visitors can enjoy plenty of outdoor activities, they should prepare for occasional rainfall, as the area experiences about 34 mm (1.3 in) of precipitation over 5 days, contributing to a noticeable humidity level of 79%. Overall, April offers a blend of cool, crisp days and lively coastal charm that captures the essence of Half Moon Bay.

April Temperature in Half Moon Bay

In April, Half Moon Bay begins to shake off the chill of winter, with temperatures gradually warming up. The minimum temperature hovers around 7°C (45°F), while the average climbs to 12°C (55°F), presenting a comfortable respite from the earlier months. This transition is marked by a striking peak, as the maximum temperature can soar to a delightful 25°C (78°F), hinting at the summer warmth to come. Compared to March, where the high barely reaches 19°C (67°F), April offers a significant boost in daytime comfort, inviting both locals and visitors to embrace the emerging spring vibe. It's a month of blossoming beauty and temperate cheer, perfect for outdoor adventures along the stunning coastline.

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

The chart illustrates April 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.
Choose your preferred temperature unit
The average of daily temperatures (24 hours) calculated across all days in the month.

April Precipitation in Half Moon Bay

April marks a significant transition in Half Moon Bay's precipitation patterns, as the region experiences a considerable drop in rainfall compared to the preceding months. With only 34 mm (1.3 in) of rain falling over 5 days, April serves as a bridge between the wetter winter months and the drier summer ahead. This sharp decline from March's 77 mm (3.0 in) highlights the shift toward a more arid climate, setting the stage for May and June, when precipitation further diminishes to just 22 mm (0.9 in) and 4 mm (0.2 in), respectively. As the season progresses, the trend becomes increasingly clear: Half Moon Bay enjoys a period of rejuvenation in spring, but soon transitions into its characteristic dry summer weather.

April Precipitation Trends in Half Moon Bay

The chart displays monthly precipitation patterns in Half Moon Bay, with values for each month alongside April's data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how April's conditions compare to those of other months.
JanFebMarAprMayJunJulAugSepOctNovDec1021017834224333274892
Data source: Precipitation data for April generated using information from the Copernicus Climate Change Service.
Choose your preferred precipitation unit

April Humidity in Half Moon Bay

In April, Half Moon Bay experiences a mild drop in humidity, settling at 79%. This trend shows a gradual decrease from the 85% in January, followed by 82% through February and March. As spring unfolds, the coastal climate begins to moderate, inviting a fresh sensation compared to the heavier, damper winter months. Interestingly, this slight decline precedes a rise in humidity again in May, when levels increase to 83%. Overall, April serves as a transitional period, where the air begins to feel less saturated, hinting at the warmer months ahead while still maintaining the characteristic coastal moisture that defines this beautiful region.

April Average Humidity in Half Moon Bay

This chart illustrates the average monthly humidity levels in Half Moon Bay, with April's data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, allowing you to see how April's humidity levels compare to other months.
JanFebMarAprMayJunJulAugSepOctNovDec85%82%82%79%83%84%87%87%86%80%79%79%
Data source: Humidity data for April generated using information from the Copernicus Climate Change Service.

April UV Index in Half Moon Bay

April marks a significant increase in UV exposure in Half Moon Bay, with the UV Index soaring to 9, placing it in the very high category. As the days lengthen and temperatures rise, the risk of sunburn becomes more pronounced, with a burn time of just 15 minutes for unprotected skin. This trend highlights a steady rise from earlier months: starting at a moderate 3 in January, the index escalated sharply through March and continues to climb into May with an even higher index of 10. As spring progresses, it's essential for residents and visitors alike to remain vigilant about sun protection. For more information on UV levels throughout the year, visit Half Moon Bay UV Index.

Maximum UV Index Levels in Half Moon Bay for April

The chart shows the monthly maximum UV Index (UVI) for Half Moon Bay in April, 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 April 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.

April Sunshine in Half Moon Bay

As April dawns in Half Moon Bay, residents bask in a remarkable 296 hours of sunshine, signaling a vibrant transition from the quieter winter months. This delightful increase marks a significant leap from 263 hours in March, and sets the stage for May's splendid 341 hours. The months ahead promise an abundance of sunlight, with June peaking at 355 hours — the sunniest time of the year. While the sun begins to set earlier in the fall, with September ushering in 299 hours, the steady climb in sunshine from January’s mere 151 hours showcases a lively awakening. April not only heralds warmer days but also invites the community to revel in the beauty of nature as it comes alive.

Monthly Sunshine Duration in Half Moon Bay: April Highlighted

The April sunshine duration represents the total number of hours Half Moon Bay experiences direct sunlight during the month of April, excluding cloudy or obstructed periods. This chart compares the sunshine duration of April with the other months of the year.
JanFebMarAprMayJunJulAugSepOctNovDec151h216h263h296h341h355h349h320h299h276h225h194h
Data source: Half Moon Bay April Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Half Moon Bay During April

In Half Moon Bay, April sees a 44% chance of sunny weather, marking a dip compared to the preceding months of March and February, which enjoy sun probabilities of 60% and 56%, respectively. This trend indicates a slight seasonal fluctuation as the spring months unfold. Following April, May bounces back with a more favorable 57% chance of sunshine, yet June encounters another slight decline at 45%. Overall, while half of April may be overcast, the transition into warmer months offers opportunities for clearer skies ahead.

Percentage of Sunny Days in April in Half Moon Bay

The chart illustrates the percentage of sunny days in Half Moon Bay throughout the year, with April 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 April chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Half Moon Bay in April

As April unfolds in Half Moon Bay, residents eagerly embrace a noticeable transformation in daylight duration, basking in an impressive 13 hours of sunlight. This is a significant leap from the 11 hours experienced in March, marking the arrival of spring with longer, brighter days. Following the gradual increase from 10 hours in February to 9 hours in January, April sets the stage for even longer days ahead, with May boasting 14 hours of daylight. This consistent gain in sunlight not only enhances outdoor activities but also uplifts moods, as the community welcomes the warmth and vibrancy that spring brings. As the year progresses, the trend of extending daylight offers a rhythm of seasonal change that invigorates the spirit of Half Moon Bay.

Average Daylight Hours in Half Moon Bay for April

The chart illustrates the variation in daylight duration in Half Moon Bay throughout the year, with April 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.

April Winds in Half Moon Bay

As spring settles in, April brings a refreshing uptick in wind speed to Half Moon Bay, with averages reaching 4.5 m/s (10 mph). This marks a subtle increase from March, where winds measured 4.2 m/s (9 mph), hinting at the shifting seasons and heralding the approaching summer breezes. Following the lighter winds of winter, where January and February saw averages of 3.5 m/s (8 mph) and 4.3 m/s (10 mph) respectively, April's inviting gusts are a precursor to the even stronger winds expected in May, which peak at 5.4 m/s (12 mph). This pattern showcases a lively transition, with April standing out as a bridge between the calm of early spring and the more vigorous summer winds that follow.

Average April Wind Speed in Half Moon Bay

The chart displays monthly wind speed patterns in Half Moon Bay, with values for each month shown alongside April's data, which is highlighted for easy comparison. It illustrates the average wind speed, offering insights into how April's wind conditions compare to the rest of the year.
JanFebMarAprMayJunJulAugSepOctNovDec3.54.34.24.5 m/s5.44.33.43.33.13.83.04.1
Data source: Half Moon Bay April wind data, generated using information from the Copernicus Climate Change Service.

How April 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 April'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.

In comparing the weather of April and January, we observe some notable differences. April generally sees slightly warmer temperatures, with a minimum of 7°C (45°F) and an average of 12°C (55°F), while January has a minimum of 5°C (41°F) and an average of 11°C (53°F). Additionally, April boasts a maximum temperature of 25°C (78°F), significantly higher than January's maximum of 20°C (68°F). Precipitation levels also vary; January experiences more rain, averaging 102 mm (4.0 in) over 9 days, compared to April's 34 mm (1.3 in) over 5 days. Humidity remains fairly consistent, with January at 85% and April at 79%. For a detailed look at January weather, visit Half Moon Bay weather in January.

April typically brings warmer temperatures compared to February, with average highs reaching 25°C (78°F) in April versus 20°C (69°F) in February. Additionally, April experiences less precipitation, averaging 34 mm (1.3 in) over about 5 days of rain, while February sees significantly more rainfall at 101 mm (4.0 in) over 9 days. Humidity levels remain relatively similar, with April at 79% and February slightly higher at 82%. For a closer look at February conditions, you can check out Half Moon Bay weather in February.

In comparing the weather between March and April, both months have similar minimum temperatures, with March slightly lower at 7°C (44°F). However, April sees a notable increase in maximum temperatures, reaching up to 25°C (78°F), compared to March's high of 19°C (67°F). Precipitation is significantly less in April with only 34 mm (1.3 in) over 5 days, while March experiences 77 mm (3.0 in) spread across 11 days. Humidity levels are also slightly lower in April at 79% versus 82% in March, contributing to a generally drier and warmer feel in April. For more detailed information on March weather, you can check Half Moon Bay weather in March.

In comparing the weather between April and May, April tends to be warmer during the day, with maximum temperatures reaching up to 25°C (78°F) compared to May’s peak of 21°C (69°F). However, May's minimum temperatures are slightly higher, starting at 9°C (48°F) versus April's 7°C (45°F). April also experiences more rainfall, accumulating 34 mm (1.3 in) over approximately 5 days, while May sees less precipitation at 22 mm (0.9 in) spread over just 2 days. The humidity levels remain fairly consistent, with May being slightly more humid at 83% compared to April's 79%. For those seeking detailed insights into the weather during this time, you can check Half Moon Bay weather in May.

April and June present distinct weather patterns, with April featuring a broader temperature range from a minimum of 7°C (45°F) to a maximum of 25°C (78°F) and experiencing 34 mm (1.3 in) of precipitation over five days. In contrast, June showcases milder temperatures with a minimum of 10°C (51°F) and a slightly higher maximum of 27°C (81°F), but remarkably, it boasts only 4 mm (0.2 in) of precipitation over the entire month, translating to no rainy days. While April tends to be more variable with higher humidity at 79%, June's humidity rises slightly to 84%, creating a warm and pleasant atmosphere. For more specific details, check out Half Moon Bay weather in June.

In comparing the weather between April and July, April tends to be significantly warmer, with temperatures ranging from a minimum of 7°C (45°F) to a maximum of 25°C (78°F). In contrast, July's temperatures are milder, with a minimum of 11°C (51°F) and a maximum of 20°C (69°F). Additionally, April experiences considerably more precipitation, totaling 34 mm (1.3 in) over 5 days, while July is quite dry with only 3 mm (0.1 in) and no rainy days. The humidity also sees a slight increase in July, reaching 87%, compared to April's 79%. For more specific details on July weather, you can check Half Moon Bay weather in July.

April weather is characterized by a broader temperature range with minimums around 7°C (45°F) and maximums reaching up to 25°C (78°F), making it a transitional month into warmer seasons. It experiences some precipitation, averaging 34 mm (1.3 in) over about 5 days, alongside a humidity level of 79%. In contrast, August offers milder temperatures, with a minimum of 11°C (53°F) and a maximum of 24°C (76°F), and generally drier conditions. It boasts only 3 mm (0.1 in) of precipitation over no rainy days, while humidity rises slightly to 87%. For a detailed look at weather specifics, check out Half Moon Bay weather in August.

April weather tends to be cooler with temperatures ranging from a minimum of 7°C (45°F) to a maximum of 25°C (78°F), averaging around 12°C (55°F). It experiences moderate rainfall, with an average precipitation of 34 mm (1.3 in) over about 5 days and a humidity level of 79%. In contrast, September boasts warmer temperatures, starting at a minimum of 11°C (52°F) and reaching up to 31°C (88°F), with an average of 16°C (62°F). Notably, precipitation is sparse in September, totaling only 3 mm (0.1 in) across no rain days, alongside a higher humidity level of 86%. For more details, check out Half Moon Bay weather in September.

April and October showcase distinct yet mild weather patterns. In April, temperatures range from a minimum of 7°C (45°F) to a maximum of 25°C (78°F), with an average of 12°C (55°F). This month experiences approximately 34 mm (1.3 in) of precipitation over about five days, accompanied by a humidity level of 79%. In contrast, October features slightly warmer conditions, with temperatures ranging from a minimum of 9°C (49°F) to a maximum of 27°C (80°F), averaging 15°C (60°F). The month sees less rainfall at around 27 mm (1.1 in) over just two days, with a similar humidity level of 80%. For more information on October weather specifics, you can explore Half Moon Bay weather in October.

In comparing the weather between April and November, both months exhibit a similar minimum temperature of 7°C (45°F) and humidity levels of 79%. However, April generally boasts a higher average temperature of 12°C (55°F) compared to November's average of 13°C (56°F) and a warmer maximum temperature of 25°C (78°F) versus November's 21°C (70°F). Precipitation is more prevalent in November, with 48 mm (1.9 in) of rainfall over 5 days compared to April's 34 mm (1.3 in) over the same number of days. To learn more about what to expect, check out Half Moon Bay weather in November.

April and December share similar average temperatures, with both months hovering around 12°C (55°F). However, April experiences a broader range, with maximum temperatures reaching up to 25°C (78°F), while December’s peak is lower at 19°C (67°F). In terms of precipitation, December is noticeably wetter, receiving 92 mm (3.6 in) over about 10 days compared to April's 34 mm (1.3 in) across just 5 days. Both months maintain a consistent humidity level of 79%, creating a similar feel in terms of moisture in the air. For more details on December weather specifically, visit Half Moon Bay weather in December.

Compare Half Moon Bay's Climate with Cities Worldwide

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

As April blankets Half Moon Bay in a refreshing transition from the cooler months, visitors can expect a delightful mix of mild temperatures and increased humidity. With an average warmth that gently rises, this month invites locals and tourists alike to enjoy outdoor activities amid picturesque coastal scenery. Despite experiencing a few rainy days, the overall atmosphere is vibrant and invigorating, setting the stage for the lush spring that follows. For more detailed insights into how April compares to other months, check out the full Half Moon Bay Climate page.