🇺🇸 Weather in Costa Mesa
Current Weather in Costa Mesa
Small Craft Advisory issued July 23 at 7:58AM PDT until July 23 at 9:00PM PDT by NWS Los Angeles/Oxnard CA
28°C
Feels like 31°C. Partly cloudy.
Map Overlays:
Hourly Forecast for Costa Mesa
18:00
27°
7%
19:00
26°
7%
20:00
23°
8%
21:00
22°
11%
22:00
21°
14%
23:00
21°
14%
00:00
20°
14%
01:00
20°
14%
02:00
19°
14%
03:00
19°
14%
04:00
19°
14%
05:00
22°
9%
06:00
22°
9%
07:00
22°
8%
08:00
23°
7%
09:00
24°
6%
10:00
24°
5%
11:00
25°
4%
12:00
26°
4%
13:00
26°
4%
14:00
26°
3%
15:00
26°
3%
16:00
26°
4%
17:00
25°
4%
14-Day Forecast for Costa Mesa
2026-07-23
Sunny
31° /
17°
2026-07-24
Sunny
26° /
19°
2026-07-25
Sunny
28° /
22°
2026-07-26
Sunny
27° /
23°
2026-07-27
Sunny
27° /
22°
2026-07-28
Sunny
26° /
22°
2026-07-29
Sunny
26° /
22°
Additional Forecasts for Costa Mesa
Air Quality
💨 US EPA Index 1 (Good)
CO (Carbon Monoxide) 96.0 μg/m³
O₃ (Ozone) 78.0 μg/m³
NO₂ (Nitrogen Dioxide) 5.7 μg/m³
SO₂ (Sulphur Dioxide) 1.4 μg/m³
PM2.5 (Fine particles) 8.5 μg/m³
PM10 (Coarse particles) 12.8 μg/m³
Historical Weather
Weather Forecasts for Other Cities in United States
Weather in Costa Mesa — FAQ
Answers refreshed each request based on current conditions in Costa Mesa.
What is the weather like right now in Costa Mesa?
Right now in Costa Mesa, United States the temperature is 27.8°C (feels like 30.6°C), with partly cloudy. Relative humidity is 55% and wind is 15.5 km/h.
What is today's high and low temperature in Costa Mesa?
Today's forecast high in Costa Mesa is 30.8°C and the overnight low is 17.3°C. The diurnal range — high minus low — depends on cloud cover; clear days swing more than overcast ones.
Will it rain in Costa Mesa today?
The chance of precipitation in Costa Mesa today is 8%. Forecast accuracy is highest within the next 6 hours and decreases steadily out to 14 days.
How often does the weather here update?
Current observations refresh every 15-60 minutes from the nearest monitoring stations operated by national meteorological agencies. The hourly forecast updates approximately every hour; the 7- and 14-day outlook is recomputed several times per day.
What does 'feels like' temperature mean?
Feels-like (apparent) temperature accounts for humidity, wind chill and direct sunshine — variables that change how the human body perceives heat or cold. On hot, humid days it can be 3-7°C above the actual reading; on cold windy days it can be 5-15°C below.
Why does the temperature in Costa Mesa differ from nearby cities?
Even short distances can change temperatures noticeably. Costa Mesa's reading reflects altitude, proximity to large bodies of water, urban heat island effects, and the exact location of the monitoring stations supplying the data. Coastal cities are typically milder and more humid than inland equivalents.