Weather StoryAlmanac, microseasons, and the day's weather story.

San Marcos, California Weather

Summer heat deepens across the valleys. Day 15 of summer. Read this microseason across nine climate regions →

San Marcos weather forecast — hour by hour, 7-day outlook, NOAA radar

San Marcos, CA
Sunday, July 5 at 11:04 AM
77
°
Clear
Feels like
81°
Humidity
57%
Wind
8 mph
Sunrise
10:45 PM
Sunset
1:01 PM
San Marcos, CA
Hour by hour · 24h
24-Hour ForecastSan Marcos, CA: 24-hour forecast. Temperatures range from 62 to 82 degrees Fahrenheit.
L 62°H 82°
San Marcos, CA
7-day forecast
  1. Today
    Jul 5
    Foggy
    —
    —
    82°64°—
  2. Monday
    Jul 6
    Foggy
    —
    —
    80°62°-2°
  3. Tuesday
    Jul 7
    Foggy
    —
    —
    79°58°-1°
  4. Wednesday
    Jul 8
    Clear
    —
    —
    83°58°+4°
  5. Thursday
    Jul 9
    Clear
    —
    —
    83°60°0°
  6. Friday
    Jul 10
    Overcast
    —
    —
    85°60°+2°
  7. Saturday
    Jul 11
    Overcast
    —
    —
    80°63°-5°
San Marcos, CA
Next 24 hours · Mild now
HOT 90°55°73°90°6a12p6p12anow 77°high 82°low 62°
San Marcos, CA
Anemometer · 24h winds · from true
NESW
From · True
W
272° · veering 8°
Direction
W
272°
Sustained
8
mph
Gust
8
mph
Peak 24h
12
avg 5
Beaufort · 3 · GENTLE BRZ
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 · pk 12 @ 5:00p
010MPHB1B2B3B4-21h-18h-15h-12h-9h-6h-3h-24hNOWpk 125SUSTGUST
−24h−18h−12h−6hnow
Light breeze veering 8° from the w.
San Marcos, CA
Barometer · 24h pressure · mb
STORMRAINCHANGEFAIRDRY9901000101010201030
Pressure · mb
994.0
-0.3 mb in 3h · steady · 29.35 inHg
Now
994.0
mb
3h
-0.3
mb
12h
-0.7
mb
24h
-2.0
mb
Regime · STORM
STORM
RAIN
CHANGE
FAIR
DRY
24h · Pressure · mb
range 993–996
9859909951000STORM|RAIN-21h-18h-15h-12h-9h-6h-3h-24hNOW996.0993.4994.0
−24h−18h−12h−6hnow
Deep low — expect rough seas, strong wind, and persistent rain.
San Marcos, CA
Air quality
45
AQI
Good
→+2 in 6h

AQI 45 (Good), driven by PM2.5. AQI flat over the last 6 hours (within ±3 points). PM2.5 at 11.9 µg/m³ (AQI 56), ratio 0.70 with 8 mph wind — characteristic of long-range haze transport rather than a local source.

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

PM 2.5DRIVERGood
11.9μg/m³
PM 10Good
17μg/m³
NO₂Good
2μg/m³
OzoneModerate
86μg/m³
UV IndexVery high
9.9

What's driving it

Ozone × UV × Sky

Ozone at AQI 41 now. With UV 11 peaking around 1 PM under clear skies, surface ozone likely climbs to AQI 62 around 1 PM.

Present
AQI 41
UV peak
11.4 at 1 PM
Sky at peak
clear
Projected peak
AQI 62

PM × Wind × Precip

PM2.5 at 11.9 µg/m³ (AQI 56), ratio 0.70 with 8 mph wind — characteristic of long-range haze transport rather than a local source.

PM2.5/PM10
0.70
Wind
light
Recent rain
0h in last 6h
Pattern
transport

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 TREND50100SUNMONTUEWEDTHUFRISATSUN7-DAY PM2.5 TREND · μg/m³300
San Marcos, CA
Sky cover · visibility · 24h
Cloud cover
4%
CLEAR
100%0%−24h−18h−12h−6hnow
Visibility
60.5mi
UNLIMITED
89 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
18:04 UTC · San Marcos, 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
18:04 UTC · San Marcos, CA · NOAA NESDIS / STAR · 5-min cadence · up to 10000 px
San Marcos, CA
Satellite · infrared · animated
San Marcos, CA
Loading IR frames…
IR · cloud-top temp© RainViewer · Carto
San Marcos, CA
Almanac · Sunday, July 5
If the first of July be rainy weather, 'twill rain more or less for four weeks together.
Civil dawn
5:17 AM
Sunrise
10:45 PM
Daylight
14h 16m
Sunset
1:01 PM
Civil dusk
8:31 PM
Planting note
Harvest early potatoes. Begin drying onions on the surface.
San Marcos, CA
The moon
Waning Gibbous
70% illuminated
Moonrise
11:04 PM
Moonset
11:08 AM
In sign
♓︎ Pisces
San Marcos, CA
Microseason
Jul 1–5

Summer heat deepens across the valleys

weather
Jan 151% of the yearDec 31

Read this microseason across nine climate regions →

San Marcos at a glance

  • Today vs. normal: 77°F — typical for the season
  • Last frost: March 6 (climatological average for this latitude)
  • Microseason: Jul 1–5
  • Planting window: Harvest early potatoes. Begin drying onions on the surface.

ZIP codes: 92069, 92078, 92096

16-Day Forecast — San Marcos

  1. Sun82°64°0%
  2. Mon80°62°1%
  3. Tue79°58°0%
  4. Wed83°58°0%
  5. Thu83°60°0%
  6. Fri85°60°0%
  7. Sat80°63°1%
  8. Sun88°62°4%
  9. Mon86°62°11%
  10. Tue87°67°12%
  11. Wed90°68°5%
  12. Thu93°71°13%
  13. Fri92°71°19%
  14. Sat86°68°15%
  15. Sun89°68°14%
  16. Mon90°64°13%

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

Live wind & temperature near San Marcos

Right now in the garden

Peak growing season

As of July 5, 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 1–5

Summer heat deepens across the valleys

Inland temperatures exceed 95°F regularly; fire danger reaches moderate to high across most of the region.

Day 186 of 365 · Wedge 37 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 San Marcos's warmest stretch (~70°F) and December its coldest (~53°F); precipitation crests in February at 2.9 inches and ebbs in August to 0.0 inches.

MonthMean tempPrecipRainy days
January54°2.4″3
February54°2.9″5
March56°1.7″3
April58°0.9″2
May62°0.3″1
June66°0.1″0
July69°0.1″0
August70°0.0″0
September69°0.1″0
October64°0.6″1
November57°0.8″2
December53°2.0″3

Regional context

By the nearest station's NOAA NCEI 1991-2020 normals, San Marcos sees 54°F Januarys and 69°F Julys, a 16°F range, plus around 11.9 inches of precipitation across 20 days.

Cool-season fronts carry San Marcos's rain: February logs 2.9 inches on 4.6 days, against August's 0.0 inches on 0.1 — winter does the heavy lifting in San Marcos. That groups San Marcos with places like Lake San Marcos, CA, Harmony Grove, CA and Elfin Forest, CA on the same cool-season storm track.

San Marcos rarely sees a hard freeze — its coldest month sits near 53°F — so planting spans most of the calendar. Heat peaks in August around 70°F, which confines cool-season crops to the shoulders of summer. San Marcos's coastal lots stay 4-7°F milder overnight than San Marcos's inland parcels.

Similar climates: Lake San Marcos, CA, Harmony Grove, CA, Elfin Forest, CA, Del Dios, CA, Vista, CA.

Naturalist notes

By late spring, western fence lizards are emerging from winter dormancy on sun-warmed retaining walls and rock edges throughout the San Marcos area.

In the longer evenings of May, the constellation Scorpius begins climbing above the southeastern horizon after dusk, its brightest star Antares glowing a steady orange.

Frequently asked

When does it freeze in San Marcos?
Frost typically leaves San Marcos by mid-March and returns to San Marcos near mid-December.
What is the rainy season in San Marcos?
San Marcos sees its heaviest rain in February (around 2.9 inches), part of roughly 12 inches a year.
What is the warmest month in San Marcos?
On average August tops the year in San Marcos at about 70°F.
What is the coldest month in San Marcos?
The coldest stretch in San Marcos falls in December, around 53°F on average.
When can I start a vegetable garden in San Marcos?
Hardy spring crops go in near mid-March in San Marcos; tender peppers and squash wait 10–14 days.
How many rainy days does San Marcos get?
San Marcos records around 20 days of measurable precipitation annually.
What hardiness zone is San Marcos?
With December around 53°F, San Marcos's zone reflects that minimum — the USDA ZIP map confirms San Marcos's band.
What is the 10-day forecast for San Marcos?
San Marcos'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 San Marcos?
See this week's day-by-day rain chances for San Marcos in the daily forecast above, and the next 24 hours in the hourly chart.
What is the weather like right now in San Marcos?
Current conditions for San Marcos and the next 24 hours — temperature, precipitation chance, and wind by the hour — are in the hourly forecast chart above.
How often is the San Marcos forecast updated?
The San Marcos forecast on this page is built from Open-Meteo weather-model data and refreshes regularly through the day.
When are sunrise and sunset in San Marcos?
Today's sunrise and sunset times for San Marcos 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 San Marcos?
The next few days in San Marcos's forecast are the most reliable; accuracy declines beyond about a week as weather-model uncertainty grows.

Climate

Set in a hot-summer Mediterranean zone, San Marcos, California swings from 54°F in the heart of winter to 69°F at midsummer — a 15°F arc.

In a typical year San Marcos records about 12 inches of precipitation on around 20 days.

San Marcos sits at 33.1°N; that 15°F seasonal swing frames planting windows and frost dates across San Marcos.

All cities in California →

San Diego, CA weather →

ZIP codes in San Marcos

  • 92078
  • 92096
  • 92069
  • 92079

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.