Today | Weather | Thursday, December 4, 2025

Active Weather Warnings

Beach Hazards Statement

Weather in Costa Mesa, California

01:29 AM

Now

54° F

Feels Like 45°

Precipitation 0 %

Wind 22 mph

Humidity 38 %

Today

Day 73°

Night 45°

Precipitation 0 %

Wind 9 mph

UV Index (0 - 11+) 3

Costa Mesa Weather Forecast Updated

42 minutes ago

Last updated on December 04, 2025 at 12:46 AM

Weather Forecast History

Last Year's Weather on This Day (December 4, 2024)

Day

63°

Night

45°

Wind

4 mph

Precipitation

0 %

Air Quality in Costa Mesa

NOW

73 AQI

Moderate air quality Dominant pollutant: PM_2.5

Pollutant Concentrations:

PM_2.5 22.91 µg/m³

PM₁₀ 32.14 µg/m³

O₃ 0.051 ppm

NO₂ 3.2 ppb

SO₂ 1 ppb

CO 0.19 ppm

NH₃ 0.3 µg/m³

NO 0 µg/m³

PM_2.5 – Fine particles <2.5μm

PM₁₀ – Inhalable particles <10μm

O₃ – Ozone

NO₂ – Nitrogen dioxide

SO₂ – Sulfur dioxide

CO – Carbon monoxide

NH₃ – Ammonia

NO – Nitric oxide

Health Recommendations:

Air quality is acceptable; however, for some pollutants, there may be a moderate health concern for a very small number of people who are unusually sensitive to air pollution.

Show raw pollutant concentrations (µg/m³)

PM_2.5 – 22.91 µg/m³

PM₁₀ – 32.14 µg/m³

O₃ – 100.08 µg/m³

NO₂ – 6 µg/m³

SO₂ – 2.7 µg/m³

CO – 215.84 µg/m³

NH₃ – 0.3 µg/m³

NO – 0 µg/m³

View Hourly Air Quality Forecast

Weather Alerts and Warnings for Costa Mesa

Moderate Expected Likely

Beach Hazards Statement

Beach Hazards Statement issued December 3 at 9:53PM PST until December 5 at 10:00AM PST by NWS San Diego CA

Dec 3, 9:53 PM → Dec 5, 10:00 AM

WHAT: Very high astronomical tides during the mornings combined
with elevated surf up to 5 to 6 feet, primarily at west-facing
beaches today, will result in minor tidal overflow and local
beach flooding.

WHERE: San Diego County Coastal Areas and Orange County
Coastal Areas.

WHEN: Through Friday morning.

IMPACTS: Minor tidal overflow, beach flooding, and coastal
erosion most likely during times of high tides. Hazardous
swimming conditions.

ADDITIONAL DETAILS: Predicted high tides at La Jolla: 7.1
feet at 734 AM Thursday, and 7.1 feet at 818 AM Friday.

+ Read More

Remain out of the water to avoid hazardous swimming conditions.

Updated: Dec 4, 12:46 AM Source: NWS Alert