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Alamo, California Weather

Summer solstice light stretched thin. Day 88 of spring. Read this microseason across nine climate regions →

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

Alamo, CA
Monday, June 15 at 11:38 AM
78
°
Clear
Feels like
84°
Humidity
53%
Wind
5 mph
Sunrise
10:45 PM
Sunset
1:31 PM
Alamo, CA
Hour by hour · 24h
24-Hour ForecastAlamo, CA: 24-hour forecast. Temperatures range from 57 to 83 degrees Fahrenheit.
L 57°H 83°
Alamo, CA
7-day forecast
  1. Today
    Jun 15
    Clear
    —
    —
    83°57°—
  2. Tuesday
    Jun 16
    Clear
    —
    —
    81°57°-2°
  3. Wednesday
    Jun 17
    Clear
    —
    —
    92°54°+11°
  4. Thursday
    Jun 18
    Clear
    —
    —
    85°52°-7°
  5. Friday
    Jun 19
    Mostly Clear
    —
    —
    81°52°-4°
  6. Saturday
    Jun 20
    Overcast
    —
    —
    78°51°-3°
  7. Sunday
    Jun 21
    Clear
    —
    —
    82°49°+4°
Alamo, CA
Next 24 hours · Mild now
HOT 90°50°70°90°6a12p6p12anow 77°high 83°low 57°
Alamo, CA
Anemometer · 24h winds · from true
NESW
From · True
WNW
284° · backing 16°
Direction
WNW
284°
Sustained
5
mph
Gust
5
mph
Peak 24h
12
avg 4
Beaufort · 2 · LIGHT 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 4 · pk 12 @ 5:00p
01020MPHB1B2B3B4B5-21h-18h-15h-12h-9h-6h-3h-24hNOWpk 135SUSTGUST
−24h−18h−12h−6hnow
A whisper of wind — leaves barely shift on the trees.
Alamo, CA
Barometer · 24h pressure · mb
STORMRAINCHANGEFAIRDRY9901000101010201030
Pressure · mb
1003.5
+0.9 mb in 3h · rising · 29.63 inHg
Now
1003.5
mb
3h
+0.9
mb
12h
+2.0
mb
24h
+1.7
mb
Regime · RAIN
STORM
RAIN
CHANGE
FAIR
DRY
24h · Pressure · mb
range 1001–1004
9951000STORM|RAIN10051010RAIN|CHG1015CHG|FAIR10201025FAIR|DRY1030-21h-18h-15h-12h-9h-6h-3h-24hNOW1003.51000.51003.5
−24h−18h−12h−6hnow
Pressure climbing out of the rain band — clearing edging in.
Alamo, CA
Air quality
48
AQI
Good
→+1 in 6h

AQI 48 (Good), driven by PM2.5. AQI flat over the last 6 hours (within ±3 points). PM2.5 at 13.0 µg/m³ (AQI 58) with a 0.69 fine-to-coarse ratio and 5 mph wind — combustion smoke trapped in calm air, not road dust.

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

PM 2.5DRIVERModerate
13.0μg/m³
PM 10Good
19μg/m³
NO₂Good
5μg/m³
OzoneModerate
78μg/m³
UV IndexHigh
7.0

What's driving it

Ozone × UV × Sky

Ozone at AQI 37 now. With UV 8.1 peaking around 1 PM under clear skies, surface ozone likely climbs to AQI 40 around 1 PM.

Present
AQI 37
UV peak
8.1 at 1 PM
Sky at peak
clear
Projected peak
AQI 40

PM × Wind × Precip

PM2.5 at 13.0 µg/m³ (AQI 58) with a 0.69 fine-to-coarse ratio and 5 mph wind — combustion smoke trapped in calm air, not road dust.

PM2.5/PM10
0.69
Wind
light
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
Alamo, CA
Sky cover · visibility · 24h
Cloud cover
3%
CLEAR
100%0%−24h−18h−12h−6hnow
Visibility
92.6mi
UNLIMITED
112 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
18:38 UTC · Alamo, 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
18:38 UTC · Alamo, CA · NOAA NESDIS / STAR · 5-min cadence · up to 10000 px
Alamo, CA
Satellite · infrared · animated
Alamo, CA
Loading IR frames…
IR · cloud-top temp© RainViewer · Carto
Alamo, CA
Almanac · Monday, June 15
A summer fog for fair, a winter fog for rain.
Civil dawn
5:15 AM
Sunrise
10:45 PM
Daylight
14h 46m
Sunset
1:31 PM
Civil dusk
9:04 PM
Planting note
Stake and prune tomato suckers. Watch for squash vine borers.
Alamo, CA
The moon
New Moon
1% illuminated
Moonrise
5:55 AM
Moonset
8:52 PM
In sign
♋︎ Cancer
Alamo, CA
Microseason
Jun 11–15

Summer solstice light stretched thin

weather
Jan 145% of the yearDec 31

Read this microseason across nine climate regions →

Alamo at a glance

  • Today vs. normal: 78°F — typical for the season
  • Last frost: April 3 (climatological average for this latitude)
  • Microseason: Jun 11–15
  • Planting window: Stake and prune tomato suckers. Watch for squash vine borers.

16-Day Forecast — Alamo

  1. Mon83°57°2%
  2. Tue81°57°0%
  3. Wed92°54°0%
  4. Thu85°52°0%
  5. Fri81°52°0%
  6. Sat78°51°0%
  7. Sun82°49°0%
  8. Mon84°50°0%
  9. Tue93°49°0%
  10. Wed96°53°0%
  11. Thu90°53°0%
  12. Fri93°50°0%
  13. Sat106°61°0%
  14. Sun108°68°0%
  15. Mon97°62°0%
  16. Tue98°59°3%

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

Right now in the garden

Peak growing season

As of June 15, 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 · June 11–15

Summer solstice light stretched thin

The sun's arc peaks; evening light lingers until past 8:30pm across the coast and Bay Area.

Day 166 of 365 · Wedge 33 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——
March——
Aprillettuce, peas, spinach, radishes—
Maylettuce, peas, spinach, radishes, tomatoes, peppers, beans, squashlettuce, peas, radishes
Junetomatoes, peppers, beans, squashlettuce, peas, radishes
Julytomatoes, peppers, beans, squashtomatoes, beans, summer squash
August—tomatoes, beans, summer squash
Septemberfall brassicas, garlic (overwinter), carrotstomatoes, beans, summer squash
Octoberfall brassicas, garlic (overwinter), carrotswinter squash, tomatoes (last)
November——
December——

A year in weather

July is Alamo's warmest stretch (~69°F) and January its coldest (~49°F); precipitation crests in January at 3.4 inches and ebbs in July to 0.0 inches.

MonthMean tempPrecipRainy days
January49°3.4″13
February51°3.3″12
March53°2.7″13
April57°1.4″9
May63°0.5″4
June67°0.0″1
July69°0.0″1
August69°0.0″1
September69°0.1″1
October64°0.5″4
November55°2.1″8
December49°3.0″12

Regional context

In Alamo, NOAA NCEI 1991-2020 normals put January near 49°F and July near 69°F — a 21°F seasonal arc — with about 17.2 inches of precipitation over 79 rainy or snowy days.

Cool-season fronts carry Alamo's rain: January logs 3.4 inches on 13.3 days, against July's 0.0 inches on 0.9 — winter does the heavy lifting in Alamo. That groups Alamo with places like San Miguel, CA, Castle Hill, CA and Diablo, CA on the same cool-season storm track.

With a coldest-month mean of 49°F, Alamo stays mostly frost-free and grows year-round. The July peak near 69°F is Alamo's real limit, pushing cool-season vegetables to spring and fall. Alamo's coastal lots stay 4-7°F milder overnight than Alamo's inland parcels.

Similar climates: San Miguel, CA, Castle Hill, CA, Diablo, CA, Walnut Creek, CA, North Gate, CA.

Frequently asked

When does it freeze in Alamo?
In Alamo, expect the last spring frost near mid-April; Alamo's first autumn frost comes around mid-November.
What is the rainy season in Alamo?
January is the wettest month in Alamo, about 3.4 inches on average; the year totals roughly 17 inches.
What is the warmest month in Alamo?
July is Alamo's warmest month, averaging about 69°F.
What is the coldest month in Alamo?
Alamo bottoms out in January, with a mean near 49°F.
When can I start a vegetable garden in Alamo?
Frost-hardy sowings begin at mid-April in Alamo; warm-season starts follow two weeks on.
How many rainy days does Alamo get?
Alamo records around 79 days of measurable precipitation annually.
What hardiness zone is Alamo?
Alamo's USDA zone comes from its January mean (49°F); enter the ZIP on the USDA lookup for the number.
What is the 10-day forecast for Alamo?
Alamo'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 Alamo?
See this week's day-by-day rain chances for Alamo in the daily forecast above, and the next 24 hours in the hourly chart.
What is the weather like right now in Alamo?
Current conditions for Alamo and the next 24 hours — temperature, precipitation chance, and wind by the hour — are in the hourly forecast chart above.
How often is the Alamo forecast updated?
The Alamo forecast on this page is built from Open-Meteo weather-model data and refreshes regularly through the day.
When are sunrise and sunset in Alamo?
Day length in Alamo peaks around the June solstice — earliest sunrise and latest sunset — and is shortest near the December solstice.
How accurate is the weather forecast for Alamo?
The next few days in Alamo's forecast are the most reliable; accuracy declines beyond about a week as weather-model uncertainty grows.

Climate

Alamo, California has a hot-summer Mediterranean climate: January averages roughly 49°F, July about 69°F, 20°F between them.

Across the year, Alamo collects about 17 inches of precipitation over roughly 79 days with measurable rain or snow.

Latitude 37.9°N gives Alamo its 20°F swing, and with it the rhythm of Alamo's growing season.

All cities in California →

San Ramon, CA weather →

ZIP codes in Alamo

  • 94507
  • 94529

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.