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April Weather in Sunnyvale, United States

Last updated: June 24, 2025

In April, the average temperature in Sunnyvale, United States hovers around 18°C (65°F). Expect minimums dipping to 2°C (35°F) and highs soaring up to 33°C (93°F). With an average humidity of 78%, you'll definitely feel the moisture in the air. Be prepared for some rainfall, as 138 mm (5.4 in) can be expected over 9 days.

April Temperature in Sunnyvale

In April in Sunnyvale, the average temperature is 18°C (65°F), with maximums reaching 33°C (93°F) and minimums dropping to as low as 2°C (35°F). Be prepared for a wide range of temperatures, making it essential to pack both warm and lightweight clothing for your travels.

April Weather in Sunnyvale: Daily Temperature Highs, Lows, and Averages

The chart illustrates April temperature patterns in Sunnyvale, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Sunnyvale, April typically has an average temperature of 18°C (65°F), with highs reaching up to 33°C (93°F) and lows dropping to around 2°C (35°F).
JanFebMarAprMayJunJulAugSepOctNovDec474960657481858479685752
Data source: Temperature data for Sunnyvale 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.

April Precipitation in Sunnyvale

In Sunnyvale in April, the precipitation amount is 138 mm (5.4 in) spread over 9 days.

April Precipitation Trends in Sunnyvale

The chart displays monthly precipitation patterns in Sunnyvale, 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. In Sunnyvale, April typically receives around 138 mm (5.4 inches) of precipitation spread over approximately 9 days.
JanFebMarAprMayJunJulAugSepOctNovDec65111117138181975697861445574
Data source: Precipitation data for April generated using information from the Copernicus Climate Change Service.
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April Humidity in Sunnyvale

In Sunnyvale in April, humidity is 78%. With an average temperature of 18°C (65°F), this humidity feels like a warm, enveloping blanket, making travel quite muggy and potentially uncomfortable, as it can leave you feeling sticky and fatigued more quickly than usual.

April Average Humidity in Sunnyvale

This chart illustrates the average monthly humidity levels in Sunnyvale, with April’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In April, average humidity in Sunnyvale is approximately 78%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec80%79%78%78%81%78%73%66%65%72%82%87%
Data source: Humidity data for April generated using information from the Copernicus Climate Change Service.

April UV Index in Sunnyvale

In Sunnyvale in April, the maximum UV index reaches 10, which corresponds to a very high Exposure Category. With a time to burn of just 15 minutes, it's crucial to take precautions. For more detailed information, you can check the Hourly UV Index in Sunnyvale.

Maximum UV Index Levels in Sunnyvale for April

The chart shows the monthly maximum UV Index (UVI) for Sunnyvale 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. In April, the maximum UV index in Sunnyvale typically reaches 10, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec478101111111110864
Data source: Sunnyvale 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.

How April Weather in Sunnyvale Compares to Other Months

Weather in Sunnyvale varies notably across the year, with each month offering distinct climate conditions. This page compares April’s weather to other months in Sunnyvale, focusing on differences in temperature, rainfall, humidity, and UV levels.

This table compares monthly weather conditions in Sunnyvale, showing how April’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather8°C (47°F)65 mm (2.6 inches)80%moderate
February Weather10°C (50°F)111 mm (4.4 inches)79%high
March Weather16°C (61°F)117 mm (4.6 inches)78%very high
April Weather18°C (65°F)138 mm (5.4 inches)78%very high
May Weather23°C (75°F)181 mm (7.1 inches)81%extreme
June Weather27°C (82°F)97 mm (3.8 inches)78%extreme
July Weather29°C (85°F)56 mm (2.2 inches)73%extreme
August Weather29°C (85°F)97 mm (3.8 inches)66%extreme
September Weather26°C (80°F)86 mm (3.4 inches)65%very high
October Weather20°C (68°F)144 mm (5.7 inches)72%very high
November Weather14°C (57°F)55 mm (2.2 inches)82%high
December Weather11°C (52°F)74 mm (2.9 inches)87%moderate

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