Today | Weather | Wednesday, February 25, 2026

Weather in Costa Mesa, California

11:47 PM
Now
Cloudy Night
55° F
Feels Like 55°
Precipitation 0 %
Wind 5 mph
Humidity 95 %
Today
Cloudy Weather
Day 72°
Night 52°
Precipitation 0 %
Wind 6 mph
UV Index (0 - 11+) 5

Costa Mesa Weather Forecast Updated

Last updated on
Weather Forecast History
Last Year's Weather on This Day (February 25, 2025)
Cloudy Weather

Day

68°

Night

46°

Wind

6 mph

UV Index

5

Precipitation

0 %

Air Quality in Costa Mesa

NOW
33 AQI
Good air quality Dominant pollutant: O3

Pollutant Concentrations:

PM2.5 4.62 µg/m³
PM10 11 µg/m³
O3 0.036 ppm
NO2 0.6 ppb
SO2 0.1 ppb
CO 0.11 ppm
NH3 0.02 µg/m³
NO 0 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)
PM2.54.62 µg/m³
PM1011 µg/m³
O370.67 µg/m³
NO21.14 µg/m³
SO20.38 µg/m³
CO122.92 µg/m³
NH30.02 µg/m³
NO0 µg/m³