Today | Weather | Monday, June 29, 2026

Weather in Costa Mesa, California

06:45 PM
Now
Cloudy Weather
66° F
Feels Like 66°
Precipitation 0 %
Wind 8 mph
UV Index (0 - 11+) 1
Humidity 72 %
Today
Cloudy Weather
Day 72°
Night 64°
Precipitation 2 %
Wind 8 mph
UV Index (0 - 11+) 5

Costa Mesa Weather Forecast Updated

3 minutes ago
Last updated on
Weather Forecast History
Last Year's Weather on This Day (June 29, 2025)
Cloudy Weather

Day

77°

Night

63°

Wind

7 mph

UV Index

12

Precipitation

0 %

Air Quality in Costa Mesa

NOW
38 AQI
Good air quality Dominant pollutant: O3

Pollutant Concentrations:

PM2.5 6.34 µg/m³
PM10 19.01 µg/m³
O3 0.041 ppm
NO2 0.1 ppb
SO2 0.3 ppb
CO 0.07 ppm
NH3 0 µg/m³
NO 0.01 µg/m³
PM2.5 – 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 considered satisfactory, and air pollution poses little or no risk.

Show raw pollutant concentrations (µg/m³)
PM2.56.34 µg/m³
PM1019.01 µg/m³
O380.42 µg/m³
NO20.28 µg/m³
SO20.84 µg/m³
CO82.68 µg/m³
NH30 µg/m³
NO0.01 µg/m³