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August Weather in Fullerton, United States

Last updated: June 24, 2025

In Fullerton, United States, the average temperature in August hovers around 23°C (74°F), making it a pleasant time to visit. However, temperatures can range from a chilly 9°C (48°F) to a sizzling 35°C (96°F). Visitors should also be prepared for some rain, as the area receives about 84 mm (3.3 in) of precipitation over 10 days, coupled with an average humidity of 84%.

August Temperature in Fullerton

In August in Fullerton, the average temperature is 23°C (74°F). Maximums can reach 35°C (96°F), while minimums can drop as low as 9°C (48°F). Overall, this month offers a warm climate, making it an ideal time for outdoor activities and exploration.

August Weather in Fullerton: Daily Temperature Highs, Lows, and Averages

The chart illustrates August temperature patterns in Fullerton, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Fullerton, August typically has an average temperature of 23°C (74°F), with highs reaching up to 35°C (96°F) and lows dropping to around 9°C (48°F).
JanFebMarAprMayJunJulAugSepOctNovDec252540496175777469514030
Data source: Temperature data for Fullerton 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.

August Precipitation in Fullerton

In Fullerton in August, the precipitation amount is 84 mm (3.3 in) over a span of 10 days.

August Precipitation Trends in Fullerton

The chart displays monthly precipitation patterns in Fullerton, with values for each month alongside August’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how August’s conditions compare to those of other months. In Fullerton, August typically receives around 84 mm (3.3 inches) of precipitation spread over approximately 10 days.
JanFebMarAprMayJunJulAugSepOctNovDec2920895714297658457832242
Data source: Precipitation data for August generated using information from the Copernicus Climate Change Service.
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August Humidity in Fullerton

In Fullerton in August, humidity is 84%. With an average temperature of 23°C (74°F), this humidity feels like a warm blanket wrapping around you, making outdoor activities feel sticky and heavy, while the air's thickness can be quite exhausting for long periods of travel.

August Average Humidity in Fullerton

This chart illustrates the average monthly humidity levels in Fullerton, with August’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In August, average humidity in Fullerton is approximately 84%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec73%81%69%71%80%83%84%84%77%72%80%79%
Data source: Humidity data for August generated using information from the Copernicus Climate Change Service.

August UV Index in Fullerton

In Fullerton in August, 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 Fullerton.

Maximum UV Index Levels in Fullerton for August

The chart shows the monthly maximum UV Index (UVI) for Fullerton in August, 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 August, the maximum UV index in Fullerton typically reaches 10, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec3569101110108643
Data source: Fullerton August 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 August Weather in Fullerton Compares to Other Months

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

This table compares monthly weather conditions in Fullerton, showing how August’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-4°C (26°F)28 mm (1.1 inches)73%moderate
February Weather-4°C (25°F)20 mm (0.8 inches)81%moderate
March Weather4°C (40°F)89 mm (3.5 inches)69%high
April Weather9°C (49°F)57 mm (2.2 inches)71%very high
May Weather16°C (61°F)142 mm (5.6 inches)80%very high
June Weather24°C (75°F)97 mm (3.8 inches)83%extreme
July Weather25°C (78°F)65 mm (2.5 inches)84%very high
August Weather23°C (74°F)84 mm (3.3 inches)84%very high
September Weather20°C (69°F)57 mm (2.2 inches)77%very high
October Weather11°C (52°F)83 mm (3.3 inches)72%high
November Weather4°C (40°F)22 mm (0.9 inches)80%moderate
December Weather-1°C (31°F)42 mm (1.6 inches)79%moderate

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