Today | Weather | Tuesday, April 7, 2026

Weather in Costa Mesa, California

09:48 AM
Now
Cloudy Weather
66° F
Feels Like 70°
Precipitation 0 %
Wind 7 mph
UV Index (0 - 11+) 4
Humidity 73 %
Today
Cloudy Weather
Day 72°
Night 59°
Precipitation 1 %
Wind 7 mph
UV Index (0 - 11+) 8

Warning: High UV Index Today: 8

High risk of harm from unprotected sun exposure. Take precautions: wear a hat, sunglasses, and apply sunscreen regularly if you’ll be outdoors for extended periods.

Costa Mesa Weather Forecast Updated

26 minutes ago
Last updated on
Weather Forecast History
Last Year's Weather on This Day (April 7, 2025)
Cloudy Weather

Day

66°

Night

50°

Wind

6 mph

UV Index

8

Precipitation

1 %

Air Quality in Costa Mesa

NOW
48 AQI
Good air quality Dominant pollutant: O3

Pollutant Concentrations:

PM2.5 6.73 µg/m³
PM10 20.79 µg/m³
O3 0.051 ppm
NO2 0.3 ppb
SO2 0.5 ppb
CO 0.11 ppm
NH3 0 µg/m³
NO 0.09 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)
PM2.56.73 µg/m³
PM1020.79 µg/m³
O3101.02 µg/m³
NO20.57 µg/m³
SO21.24 µg/m³
CO127.46 µg/m³
NH30 µg/m³
NO0.09 µg/m³