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October Weather in Costa Mesa, United States

Last updated: June 24, 2025

In October, the average temperature in Costa Mesa, United States is a pleasant 20°C (69°F). Visitors can expect a minimum temperature of 11°C (52°F) and a maximum reaching up to 38°C (101°F). With an average humidity of 67%, the weather is generally comfortable, though be prepared for brief showers, as precipitation amounts to 9 mm (0.4 in) over 2 days.

October Temperature in Costa Mesa

In October in Costa Mesa, the average temperature is 20°C (69°F). Maximums can reach 38°C (101°F), and minimums can be as low as 11°C (52°F). This makes Costa Mesa an ideal destination for travelers seeking a warm climate while still having cooler nights to enjoy outdoor activities.

October Weather in Costa Mesa: Daily Temperature Highs, Lows, and Averages

The chart illustrates October temperature patterns in Costa Mesa, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Costa Mesa, October typically has an average temperature of 20°C (69°F), with highs reaching up to 38°C (101°F) and lows dropping to around 11°C (52°F).
JanFebMarAprMayJunJulAugSepOctNovDec575759636467727372696357
Data source: Temperature data for Costa Mesa 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.

October Precipitation in Costa Mesa

In Costa Mesa in October, the precipitation amount is 9 mm (0.4 in) over the course of 2 days.

October Precipitation Trends in Costa Mesa

The chart displays monthly precipitation patterns in Costa Mesa, with values for each month alongside October’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how October’s conditions compare to those of other months. In Costa Mesa, October typically receives around 9 mm (0.4 inches) of precipitation spread over approximately 2 days.
JanFebMarAprMayJunJulAugSepOctNovDec6552552312432391868
Data source: Precipitation data for October generated using information from the Copernicus Climate Change Service.
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October Humidity in Costa Mesa

In Costa Mesa in October, humidity is 67%. With an average temperature of 20°C (69°F), this humidity feels like a warm, gentle embrace that clings to your skin, creating a comfortable yet slightly sticky atmosphere that can be refreshing while exploring the sights, provided you stay hydrated and take breaks in the shade.

October Average Humidity in Costa Mesa

This chart illustrates the average monthly humidity levels in Costa Mesa, with October’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In October, average humidity in Costa Mesa is approximately 67%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec74%79%75%71%70%72%73%69%68%67%68%71%
Data source: Humidity data for October generated using information from the Copernicus Climate Change Service.

October UV Index in Costa Mesa

In Costa Mesa in October, the maximum UV index is 7, which corresponds to the high Exposure Category. This means that the time to burn is approximately 25 minutes. For more detailed information, you can check the Hourly UV Index in Costa Mesa.

Maximum UV Index Levels in Costa Mesa for October

The chart shows the monthly maximum UV Index (UVI) for Costa Mesa in October, 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 October, the maximum UV index in Costa Mesa typically reaches 7, which falls under the high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec468101011111010754
Data source: Costa Mesa October 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 October Weather in Costa Mesa Compares to Other Months

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

This table compares monthly weather conditions in Costa Mesa, showing how October’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather14°C (57°F)65 mm (2.5 inches)74%moderate
February Weather14°C (58°F)52 mm (2.0 inches)79%high
March Weather15°C (60°F)55 mm (2.2 inches)75%very high
April Weather17°C (63°F)23 mm (0.9 inches)70%very high
May Weather18°C (64°F)12 mm (0.5 inches)70%very high
June Weather20°C (68°F)4 mm (0.2 inches)72%extreme
July Weather22°C (72°F)3 mm (0.1 inches)73%extreme
August Weather23°C (73°F)2 mm (0.1 inches)69%very high
September Weather22°C (72°F)3 mm (0.1 inches)68%very high
October Weather20°C (69°F)9 mm (0.4 inches)67%high
November Weather17°C (63°F)18 mm (0.7 inches)68%moderate
December Weather14°C (58°F)68 mm (2.7 inches)71%moderate

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