Today | Weather | Thursday, February 5, 2026

Weather in Costa Mesa, California

05:33 PM
Now
Cloudy Night
68° F
Feels Like 64°
Precipitation 5 %
Wind 7 mph
Humidity 60 %
Today
Cloudy Weather
Day 79°
Night 55°
Precipitation 25 %
Wind 5 mph
UV Index (0 - 11+) 4

Costa Mesa Weather Forecast Updated

24 minutes ago
Last updated on
Weather Forecast History
Last Year's Weather on This Day (February 5, 2025)
Rainy Weather

Day

63°

Night

55°

Wind

6 mph

UV Index

1

Precipitation

55 %

Air Quality in Costa Mesa

NOW
153 AQI
Unhealthy air quality Dominant pollutant: PM2.5

Pollutant Concentrations:

PM2.5 60.88 µg/m³
PM10 87.33 µg/m³
O3 0.060 ppm
NO2 0.3 ppb
SO2 0.1 ppb
CO 0.27 ppm
NH3 0 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:

Everyone may begin to experience health effects; members of sensitive groups may experience more serious health effects.

Show raw pollutant concentrations (µg/m³)
PM2.560.88 µg/m³
PM1087.33 µg/m³
O3117.67 µg/m³
NO20.63 µg/m³
SO20.32 µg/m³
CO314.3 µg/m³
NH30 µg/m³
NO0 µg/m³