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Costa Mesa, California Weather

Warm winds drive dryness inland. Day 16 of summer. Read this microseason across nine climate regions →

Costa Mesa weather forecast — hour by hour, 7-day outlook, NOAA radar

Costa Mesa, CA
Monday, July 6 at 6:59 AM
64
°
Clear
Feels like
67°
Humidity
91%
Wind
2 mph
Sunrise
10:47 PM
Sunset
1:05 PM
Costa Mesa, CA
Hour by hour · 24h
24-Hour ForecastCosta Mesa, CA: 24-hour forecast. Temperatures range from 59 to 77 degrees Fahrenheit.
L 59°H 77°
Costa Mesa, CA
7-day forecast
  1. Today
    Jul 6
    Mostly Clear
    —
    —
    77°61°—
  2. Tuesday
    Jul 7
    Mostly Clear
    —
    —
    78°59°+1°
  3. Wednesday
    Jul 8
    Clear
    —
    —
    85°68°+7°
  4. Thursday
    Jul 9
    Clear
    —
    —
    83°69°-2°
  5. Friday
    Jul 10
    Clear
    —
    —
    78°68°-5°
  6. Saturday
    Jul 11
    Partly Cloudy
    —
    —
    78°68°0°
  7. Sunday
    Jul 12
    Overcast
    —
    —
    79°67°+1°
Costa Mesa, CA
Next 24 hours · Cool now
54°68°82°6a12p6p12anow 61°high 77°low 59°
Costa Mesa, CA
Anemometer · 24h winds · from true
NESW
From · True
W
270° · veering 49°
Direction
W
270°
Sustained
2
mph
Gust
5
mph
Peak 24h
10
avg 5 mph
Beaufort · 1 · LIGHT AIR
0
CALM
<1
1
LIGHT AIR
1–3
2
LIGHT BRZ
4–7
3
GENTLE BRZ
8–12
4
MOD BRZ
13–18
5
FRESH BRZ
19–24
6
STRONG BRZ
25–31
7
NEAR GALE
32–38
24h · sust vs gust · mph
avg 5 mph · pk 10 mph @ 2:00p
01020MPHB1B2B3B4B5-21h-18h-15h-12h-9h-6h-3h-24hNOWpk 134SUSTGUST
−24h−18h−12h−6hnow
A whisper of wind — leaves barely shift on the trees.
Costa Mesa, CA
Barometer · 24h pressure · mb
STORMRAINCHANGEFAIRDRY9901000101010201030
Pressure · mb
1010.0
-0.2 mb in 3h · steady · 29.83 inHg
Now
1010.0
mb
3h
-0.2
mb
12h
0.0
mb
24h
-2.4
mb
Regime · RAIN
STORM
RAIN
CHANGE
FAIR
DRY
24h · Pressure · mb
range 1010–1013
9951000STORM|RAIN10051010RAIN|CHG1015CHG|FAIR10201025FAIR|DRY1030-21h-18h-15h-12h-9h-6h-3h-24hNOW1013.01009.81009.9
Damp, unsettled regime — wet weather lingers nearby.
Costa Mesa, CA
Air quality
31
AQI
Good
→-1 in 6h

AQI 31 (Good), driven by PM2.5. AQI flat over the last 6 hours (within ±3 points). PM2.5 at 8.0 µg/m³ (AQI 44) with a 0.73 fine-to-coarse ratio and 2 mph wind — combustion smoke trapped in stagnant air, not road dust.

OK No precautions needed for the general population; unusually sensitive individuals may consider limiting prolonged outdoor exertion.

PM 2.5DRIVERGood
8.0μg/m³
PM 10Good
11μg/m³
NO₂Good
14μg/m³
OzoneGood
41μg/m³
UV IndexLow
0.1

What's driving it

PM × Wind × Precip

PM2.5 at 8.0 µg/m³ (AQI 44) with a 0.73 fine-to-coarse ratio and 2 mph wind — combustion smoke trapped in stagnant air, not road dust.

PM2.5/PM10
0.73
Wind
calm
Recent rain
0h in last 6h
Pattern
stagnant smoke

Trends

Seven days of AQI and PM2.5.

Hourly air-quality data from the Copernicus Atmosphere Monitoring Service, charted across the past and next several days. Dashed lines mark the AQI breakpoints at 50 (Good → Moderate) and 100 (Moderate → Unhealthy for Sensitive Groups).

7-DAY AQI TREND50100MONTUEWEDTHUFRISATSUNMON7-DAY PM2.5 TREND · μg/m³300
Costa Mesa, CA
Sky cover · visibility · 24h
Cloud cover
13%
CLEAR
100%0%−24h−18h−12h−6hnow
Visibility
26.9mi
UNLIMITED
59 mi0 mi−24h−18h−12h−6hnow
Earth · GOES-19 ABI
Full Disk · Visible · GeoColor
GOES-19 full disk Visible · GeoColor
True-color daytime, blue/IR sandwich at night
13:59 UTC · Costa Mesa, CA · NOAA NESDIS / STAR · up to 10848 px
Continental US · GOES-19 ABI
CONUS Sector · Visible · GeoColor
GOES-19 CONUS Visible · GeoColor
Daytime true-color, blue-light/IR sandwich at night
13:59 UTC · Costa Mesa, CA · NOAA NESDIS / STAR · 5-min cadence · up to 10000 px
Costa Mesa, CA
Satellite · infrared · animated
Costa Mesa, CA
Loading IR frames…
IR · cloud-top temp© RainViewer · Carto
Costa Mesa, CA
Almanac · Monday, July 6
When the stars begin to huddle, the earth will soon become a puddle.
Civil dawn
5:19 AM
Sunrise
10:47 PM
Daylight
14h 18m
Sunset
1:05 PM
Civil dusk
8:35 PM
Planting note
Sow fall broccoli and cabbage indoors for transplant in 4 weeks.
Costa Mesa, CA
The moon
Last Quarter
62% illuminated
Moonrise
11:35 PM
Moonset
12:13 PM
In sign
♓︎ Pisces
Costa Mesa, CA
Microseason
Jul 6–10

Warm winds drive dryness inland

weather
Jan 151% of the yearDec 31

Read this microseason across nine climate regions →

Costa Mesa at a glance

  • Today vs. normal: 14°F below the seasonal normal for this latitude
  • Last frost: March 9 (climatological average for this latitude)
  • Microseason: Jul 6–10
  • Planting window: Sow fall broccoli and cabbage indoors for transplant in 4 weeks.

ZIP codes: 92626, 92627

16-Day Forecast — Costa Mesa

  1. Mon77°61°0%
  2. Tue78°59°0%
  3. Wed85°68°0%
  4. Thu83°69°0%
  5. Fri78°68°0%
  6. Sat78°68°0%
  7. Sun79°67°4%
  8. Mon81°69°7%
  9. Tue84°70°5%
  10. Wed91°72°2%
  11. Thu96°79°1%
  12. Fri96°79°6%
  13. Sat91°75°6%
  14. Sun85°73°5%
  15. Mon85°73°3%
  16. Tue84°72°3%

Forecast data from Open-Meteo (CC BY 4.0).

Live wind & temperature near Costa Mesa

Right now in the garden

Peak growing season

As of July 6, the growing season is at its peak — frost is months away. Continue succession-planting beans and summer squash. Start fall brassicas (broccoli, cabbage, kale) from seed indoors for transplanting in late summer.

January 1–5: New year in coastal mist.January 6–10: Hills hold the winter cold.January 11–15: Light lengthens over wet earth.January 16–20: The green pulse quickens.January 21–25: Spring green spreads inland.January 26–31: Winter's grip releases.February 1–5: Fog lifts, flowers open.February 6–10: Blooms erupt across chaparral.February 11–15: Winter blooms at their peak.February 16–20: Rivers recede, flowers spread.February 21–25: Earth warms, flowers rush upslope.February 26–28: Spring advances on cool winds.March 1–5: Grass and trees bud and break.March 6–10: Insects wake and feed.March 11–15: Blossoms crown the hillsides.March 16–20: Monarch chrysalis emergence.March 21–25: Light overtakes dark at equinox.March 26–31: California poppy ablaze.April 1–5: Spring rain feeds the seedlings.April 6–10: Warblers flood the understory.April 11–15: Allen's hummingbirds in courtship dives.April 16–20: Coastal fog settles; sun breaks midday.April 21–25: Oak canopies full and green.April 26–30: Chaparral awakens after spring rains.May 1–5: Coastal wildflowers at their peak.May 6–10: Gray whales complete their migration north.May 11–15: Redwood coast in cool shade.May 16–20: Fog and sun in daily rhythm.May 21–25: Summer approaches; hills turn gold.May 26–31: Dry season begins; tule fog in valleys.June 1–5: Coastal fog thickens at dawn.June 6–10: California poppies fade as heat rises.June 11–15: Summer solstice light stretched thin.June 16–20: Bay laurel fragrance sweetens shade.June 21–25: Longest daylight, driest air.June 26–30: Fog banks mask the turning tide.July 1–5: Summer heat deepens across the valleys.July 6–10: Warm winds drive dryness inland.July 11–15: Pacific high settles in firmly.July 16–20: Young hawks take to the thermals.July 21–25: Peak fire season, peak heat.July 26–31: Chaparral poised for ignition.August 1–5: August begins in scorching stillness.August 6–10: Autumn's first cool breath arrives.August 11–15: Cool winds signal the turning year.August 16–20: Evening cicada chorus.August 21–25: Marine layer descent.August 26–31: Monarch staging begins.September 1–5: Fire season intensity.September 6–10: Dew on drying grasses.September 11–15: Raptor passage begins.September 16–20: Equinox descent.September 21–25: Ceanothus blooms again.September 26–30: Insects retreat below.October 1–5: Creeks begin to whisper.October 6–10: Santa Ana wind season.October 11–15: Wildflower anticipation.October 16–20: Chaparral embers glow.October 21–25: First atmospheric river looms.October 26–31: Rains return at last.November 1–5: Coast live oak leaves turn amber.November 6–10: California lilac blooms in winter light.November 11–15: First rain greens the chaparral.November 16–20: Coastal fog thickens as storms approach.November 21–25: Thanksgiving rains swell the valleys.November 26–30: Autumn's last breath yields to winter.December 1–5: December arrives, storms accelerate.December 6–10: Winter solstice season intensifies.December 11–15: Deep winter: rivers at flood stage.December 16–20: Winter salmon runs peak in northern rivers.December 21–25: Winter solstice: the sun turns.December 26–31: Year's end in wind and rain.🌱February 14 — First skunk-cabbage spathes thaw their way up☀️March 20 — Spring equinox — day and night balance🌸April 5 — Cherry blossoms peak in the parks🐦May 10 — Warbler migration peaks along the coast✨May 25 — First fireflies scout the meadows at dusk🌞June 21 — Summer solstice — longest day🦗July 25 — Peak cicada chorus in the afternoons🌊August 18 — Warmest sea-surface temperatures of the year🍂September 22 — Autumn equinox — the slow turn❄️October 25 — First widespread frost in the suburbs🍁November 10 — Peak leaf color across the Hudson Valley🌙December 21 — Winter solstice — longest night

Microseason · July 6–10

Warm winds drive dryness inland

Offshore heating creates persistent southeasterly winds; fog-free mornings are rare; inland valleys exceed 100°F.

Day 187 of 365 · Wedge 38 of 72

The solar year drawn as a wheel of 72 five-day windows. Each wedge is one microseason; the four colored arcs mark winter, spring, summer, and autumn; the small icons sit at notable phenological events. The crimson pointer creeps clockwise as the year turns.

Planting calendar

MonthPlantHarvest
January——
February——
Marchlettuce, peas, spinach, radishes—
Aprillettuce, peas, spinach, radishes, tomatoes, peppers, beans, squash—
Maytomatoes, peppers, beans, squashlettuce, peas, radishes
Junetomatoes, peppers, beans, squashlettuce, peas, radishes
July—tomatoes, beans, summer squash
August—tomatoes, beans, summer squash
September—tomatoes, beans, summer squash
Octoberfall brassicas, garlic (overwinter), carrotswinter squash, tomatoes (last)
Novemberfall brassicas, garlic (overwinter), carrots—
December——

A year in weather

August is Costa Mesa's warmest stretch (~73°F) and January its coldest (~54°F); precipitation crests in February at 2.5 inches and ebbs in August to 0.0 inches.

MonthMean tempPrecipRainy days
January54°2.3″9
February56°2.5″8
March58°2.0″9
April61°0.9″7
May64°0.3″4
June68°0.0″2
July72°0.1″1
August73°0.0″0
September72°0.0″2
October68°0.3″3
November60°1.1″6
December54°1.8″7

Regional context

Per NOAA NCEI 1991-2020 normals, Costa Mesa runs from a 54°F January mean to 72°F in July, a 18°F seasonal spread, with near 11.3 inches of precipitation across about 57 wet days.

Cool-season fronts carry Costa Mesa's rain: February logs 2.5 inches on 7.6 days, against August's 0.0 inches on 0.2 — winter does the heavy lifting in Costa Mesa. That cool-season-wet pattern aligns Costa Mesa with places like Fountain Valley, CA, Newport Beach, CA and Santa Ana, CA.

Hard freezes are rare in Costa Mesa: the coldest month averages 54°F, so Costa Mesa's growing window runs most of the year. August is the hottest stretch near 73°F, pushing cool-season crops to the milder shoulder months. Within Costa Mesa, low or inland lots lose 3-5°F overnight versus Costa Mesa's coastal ground.

Similar climates: Fountain Valley, CA, Newport Beach, CA, Santa Ana, CA, Huntington Beach, CA, Midway City, CA.

Naturalist notes

By late May in coastal Southern California, western scrub jays are gathering nesting material and carrying it into live oaks and ornamental pines at the latitude of Costa Mesa.

Late spring sunsets near 33.7°N extend twilight past 8 PM, and Venus often sits bright and unmistakable in the western sky well before full dark arrives.

Frequently asked

When does it freeze in Costa Mesa?
Costa Mesa's last spring frost lands near mid-March, and in Costa Mesa the first fall frost follows around mid-December.
What is the rainy season in Costa Mesa?
February is the wettest month in Costa Mesa, about 2.5 inches on average; the year totals roughly 11 inches.
What is the warmest month in Costa Mesa?
The warmest stretch in Costa Mesa comes in August, around 73°F on average.
What is the coldest month in Costa Mesa?
On average January is the chilliest month in Costa Mesa, about 54°F.
When can I start a vegetable garden in Costa Mesa?
Frost-hardy sowings begin at mid-March in Costa Mesa; warm-season starts follow two weeks on.
How many rainy days does Costa Mesa get?
Expect roughly 57 wet days a year in Costa Mesa.
What hardiness zone is Costa Mesa?
Costa Mesa's hardiness zone tracks its winter low; with January near 54°F, check the USDA ZIP map for the exact zone.
What is the 10-day forecast for Costa Mesa?
Costa Mesa's extended outlook — daily high and low temperatures and precipitation chances for each upcoming day — is in the daily forecast above.
Will it rain this week in Costa Mesa?
See this week's day-by-day rain chances for Costa Mesa in the daily forecast above, and the next 24 hours in the hourly chart.
What is the weather like right now in Costa Mesa?
Current conditions for Costa Mesa and the next 24 hours — temperature, precipitation chance, and wind by the hour — are in the hourly forecast chart above.
How often is the Costa Mesa forecast updated?
The Costa Mesa forecast on this page is built from Open-Meteo weather-model data and refreshes regularly through the day.
When are sunrise and sunset in Costa Mesa?
Today's sunrise and sunset times for Costa Mesa are in the Almanac section above, along with civil dawn, civil dusk, and day length. Day length is longest near the summer solstice and shortest near the winter solstice.
How accurate is the weather forecast for Costa Mesa?
The next few days in Costa Mesa's forecast are the most reliable; accuracy declines beyond about a week as weather-model uncertainty grows.

Climate

Costa Mesa, California has a hot-summer Mediterranean climate: January averages roughly 54°F, July about 72°F, 18°F between them.

Across the year, Costa Mesa collects about 11 inches of precipitation over roughly 57 days with measurable rain or snow.

At 33.7°N, Costa Mesa's 18°F summer-to-winter swing sets when Costa Mesa's gardens wake and when frost returns.

All cities in California →

Mission Viejo, CA weather →

ZIP codes in Costa Mesa

  • 92626
  • 92627
  • 92628

Climate normals from the Open-Meteo Climate API. Köppen approximation from NOAA NCEI U.S. Climate Regions. See methodology for data sources, editorial rules, and corrections. Maintainer: Brian Tighe.