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

San Juan, Texas Weather

Cicadas claim the scorching afternoon. Day 15 of summer. Read this microseason across nine climate regions →

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

San Juan, TX
Sunday, July 5 at 2:18 PM
96
°
Clear
Feels like
106°
Humidity
45%
Wind
8 mph
Sunrise
1:45 AM
Sunset
3:28 PM
San Juan, TX
Hour by hour · 24h
24-Hour ForecastSan Juan, TX: 24-hour forecast. Temperatures range from 78 to 98 degrees Fahrenheit.
L 78°H 98°
San Juan, TX
7-day forecast
  1. Today
    Jul 5
    Mostly Clear
    —
    —
    98°79°—
  2. Monday
    Jul 6
    Overcast
    —
    —
    97°78°-1°
  3. Tuesday
    Jul 7
    Overcast
    14%
    —
    101°79°+4°
  4. Wednesday
    Jul 8
    Clear
    —
    —
    101°79°0°
  5. Thursday
    Jul 9
    Overcast
    —
    —
    97°78°-4°
  6. Friday
    Jul 10
    Overcast
    25%
    —
    96°80°-1°
  7. Saturday
    Jul 11
    Overcast
    16%
    —
    96°81°0°
San Juan, TX
Next 24 hours · Hot now
HOT 90°74°88°102°12p6p12a6anow 96°high 98°low 78°
San Juan, TX
Anemometer · 24h winds · from true
NESW
From · True
SE
138° · veering 7°
Direction
SE
138°
Sustained
8
mph
Gust
11
mph
Peak 24h
26
avg 11
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 11 · pk 26 @ 10:00p
0102030MPHB1B2B3B4B5B6-21h-18h-15h-12h-9h-6h-3h-24hNOWpk 2510SUSTGUST
−24h−18h−12h−6hnow
Light breeze veering 7° from the se.
San Juan, TX
Barometer · 24h pressure · mb
STORMRAINCHANGEFAIRDRY9901000101010201030
Pressure · mb
1008.7
-1.8 mb in 3h · falling · 29.79 inHg
Now
1008.7
mb
3h
-1.8
mb
12h
-1.0
mb
24h
-0.5
mb
Regime · RAIN
STORM
RAIN
CHANGE
FAIR
DRY
24h · Pressure · mb
range 1008–1011
1000STORM|RAIN10051010RAIN|CHG1015CHG|FAIR10201025FAIR|DRY1030-21h-18h-15h-12h-9h-6h-3h-24hNOW1011.11008.21008.9
−24h−18h−12h−6hnow
Pressure giving way — clouds thicken and rain edges closer.
San Juan, TX
Air quality
27
AQI
Good
→0 in 6h

AQI 27 (Good), driven by Ozone. AQI flat over the last 6 hours (within ±3 points). Ozone at AQI 32 now. With UV 11 peaking around 1 PM under clear skies, surface ozone likely climbs to AQI 46 around 1 PM.

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

PM 2.5Good
5.1μg/m³
PM 10Good
7μg/m³
NO₂Good
1μg/m³
OzoneDRIVERModerate
67μg/m³
UV IndexExtreme
10.7

What's driving it

Ozone × UV × Sky

Ozone at AQI 32 now. With UV 11 peaking around 1 PM under clear skies, surface ozone likely climbs to AQI 46 around 1 PM.

Present
AQI 32
UV peak
10.7 at 1 PM
Sky at peak
clear
Projected peak
AQI 46

PM × Wind × Precip

PM2.5 at 5.1 µg/m³, PM10 at 7.1 µg/m³ — typical background levels with no transport signature.

PM2.5/PM10
0.72
Wind
light
Recent rain
0h in last 6h
Pattern
background

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 Juan, TX
Sky cover · visibility · 24h
Cloud cover
14%
CLEAR
100%0%−24h−18h−12h−6hnow
Visibility
84.6mi
UNLIMITED
104 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
19:18 UTC · San Juan, TX · 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
19:18 UTC · San Juan, TX · NOAA NESDIS / STAR · 5-min cadence · up to 10000 px
San Juan, TX
Satellite · infrared · animated
San Juan, TX
Loading IR frames…
IR · cloud-top temp© RainViewer · Carto
San Juan, TX
Almanac · Sunday, July 5
If the first of July be rainy weather, 'twill rain more or less for four weeks together.
Civil dawn
6:20 AM
Sunrise
1:45 AM
Daylight
13h 43m
Sunset
3:28 PM
Civil dusk
8:56 PM
Planting note
Harvest early potatoes. Begin drying onions on the surface.
San Juan, TX
The moon
Waning Gibbous
70% illuminated
Moonrise
11:43 PM
Moonset
11:50 AM
In sign
♓︎ Pisces
San Juan, TX
Microseason
Jul 1–5

Cicadas claim the scorching afternoon

plant
Jan 151% of the yearDec 31

Read this microseason across nine climate regions →

San Juan at a glance

  • Today vs. normal: 11°F above the seasonal normal for this latitude
  • Last frost: January 23 (climatological average for this latitude)
  • Microseason: Jul 1–5
  • Planting window: Harvest early potatoes. Begin drying onions on the surface.

ZIP code: 78589

16-Day Forecast — San Juan

  1. Sun98°79°1%
  2. Mon97°78°5%
  3. Tue101°79°14%
  4. Wed101°79°5%
  5. Thu97°78°9%
  6. Fri96°80°25%
  7. Sat96°81°16%
  8. Sun98°81°15%
  9. Mon100°79°20%
  10. Tue104°77°7%
  11. Wed106°78°9%
  12. Thu104°77°4%
  13. Fri105°79°3%
  14. Sat112°80°11%
  15. Sun95°81°4%
  16. Mon104°79°6%

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

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: Frost quiets the live oaks.January 6–10: Still water thickens with ice.January 11–15: Springs begin to move beneath ice.January 16–20: Cardinal dawn calls grow bolder.January 21–25: Late January thaw pulses.January 26–31: Last freeze locks the land.February 1–5: February's lengthening light.February 6–10: Warming winds thaw the margin.February 11–15: Magnolia blooms break the gray.February 16–20: Mockingbirds resume the dawn chorus.February 21–25: Rain replaces the last snow.February 26–28: Mist clings to greening valleys.March 1–5: The green pulse awakens.March 6–10: Hibernators emerge to call.March 11–15: Dogwood and redbud ignite.March 16–20: Swallowtails emerge from winter silk.March 21–25: Light crowns the dogwood canopy.March 26–31: Redbud cascades over the thaw.April 1–5: Thunder announces the wet season.April 6–10: Barn swallows carve the warming sky.April 11–15: Magnolia blooms and falls in a breath.April 16–20: First rainbows arch over thunderheads.April 21–25: Reeds push through marsh water.April 26–30: Frost retreats; seedlings rise free.May 1–5: Warblers flood the canopy in waves.May 6–10: Tulip poplar lights the forest crown.May 11–15: Shad pulse upstream through rapids.May 16–20: Roses open on the Piedmont edge.May 21–25: Fireflies scout the humid dusk.May 26–31: Frog choruses rise from every wetland.June 1–5: Fireflies pulse through the magnolias.June 6–10: Kudzu climbs deeper into green.June 11–15: Sun climbs to its northern throne.June 16–20: Heat settles and the rain begins.June 21–25: The longest day turns toward shadow.June 26–30: Fireflies drift through Spanish moss.July 1–5: Cicadas claim the scorching afternoon.July 6–10: Thunderheads boil and break at dusk.July 11–15: Thunder builds each drowsy afternoon.July 16–20: Cicadas claim the long noon.July 21–25: Dog days drape the earth in haze.July 26–31: Katydids begin their rasping chorus.August 1–5: Dusk arrives one minute earlier each night.August 6–10: Meteorological summer's turning page.August 11–15: Cool winds gather at the margins.August 16–20: Dog-day cicadas rise.August 21–25: Heat breaks in creek beds.August 26–31: Monarchs gather strength.September 1–5: Harvests begin in earnest.September 6–10: Dew beads on resurrection fern.September 11–15: Raptors trail the thermals.September 16–20: Day and dark find balance.September 21–25: Thunder quiets the land.September 26–30: Insects retreat below.October 1–5: Swamp waters recede.October 6–10: Maples ignite the ridge.October 11–15: Asters crown the meadows.October 16–20: Crickets sing at dusk.October 21–25: Frost paints the garden.October 26–31: Light rains whisper down.November 1–5: Sweetgum Turns Crimson.November 6–10: Camellia Blooms Break Through.November 11–15: Earth Stiffens Underfoot.November 16–20: Bare Limbs Hold the Light.November 21–25: First Frost Grips the High Ground.November 26–30: North Wind Strips the Last Leaves.December 1–5: Darkness Falls Before Dinner.December 6–10: Winter Locks the Land.December 11–15: Wildlife Retreats to Shelter.December 16–20: Ice Edges Deepen Inward.December 21–25: The Sun Begins its Return.December 26–31: The Year Turns in Silence.🌱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

Cicadas claim the scorching afternoon

Dog-day cicadas emerge in waves, their rasp dominating every sunny hour; heat peaks above 90 degrees daily.

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——
Februarylettuce, peas, spinach, radishes—
Marchlettuce, peas, spinach, radishes, tomatoes, peppers, beans, squash—
Apriltomatoes, peppers, beans, squash—
Maytomatoes, peppers, beans, squashlettuce, peas, radishes
June—lettuce, 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

The year in San Juan tops out in August (~87°F) and dips lowest in January (~61°F), with September wettest at 2.9 inches and March driest at 1.0 inches.

MonthMean tempPrecipRainy days
January61°1.2″12
February63°1.2″12
March71°1.0″13
April76°2.0″12
May81°2.4″16
June85°1.6″13
July86°1.7″11
August87°1.9″13
September82°2.9″19
October77°2.3″12
November69°1.1″11
December63°1.0″10

Regional context

Per NOAA NCEI 1991-2020 normals, San Juan runs from a 61°F January mean to 86°F in July, a 26°F seasonal spread, with near 20.4 inches of precipitation across about 155 wet days.

Summer convection drives San Juan's precipitation: September logs 2.9 inches on 18.8 rainy days, against March's 1.0 inches on 12.8 — warm-season storms carry San Juan's moisture. That summer-storm rhythm groups San Juan with places like Alamo, TX, North Alamo, TX and Pharr, TX.

Hard freezes are rare in San Juan: the coldest month averages 61°F, so San Juan's growing window runs most of the year. August is the hottest stretch near 87°F, pushing cool-season crops to the milder shoulder months. Within San Juan, low or inland lots lose 3-5°F overnight versus San Juan's coastal ground.

Similar climates: Alamo, TX, North Alamo, TX, Pharr, TX, Lopezville, TX, South Alamo, TX.

Frequently asked

When does it freeze in San Juan?
Frost typically leaves San Juan by mid-February and returns to San Juan near mid-December.
What is the rainy season in San Juan?
San Juan sees its heaviest rain in September (around 2.9 inches), part of roughly 20 inches a year.
What is the warmest month in San Juan?
August is San Juan's warmest month, averaging about 87°F.
What is the coldest month in San Juan?
San Juan bottoms out in January, with a mean near 61°F.
When can I start a vegetable garden in San Juan?
San Juan's last frost (mid-February) cues hardy greens; in San Juan, hold heat-lovers two weeks past.
How many rainy days does San Juan get?
Expect roughly 155 wet days a year in San Juan.
What hardiness zone is San Juan?
San Juan's hardiness zone tracks its winter low; with January near 61°F, check the USDA ZIP map for the exact zone.
What is the 10-day forecast for San Juan?
San Juan'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 Juan?
See this week's day-by-day rain chances for San Juan in the daily forecast above, and the next 24 hours in the hourly chart.
What is the weather like right now in San Juan?
Current conditions for San Juan 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 Juan forecast updated?
The San Juan 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 Juan?
Today's sunrise and sunset times for San Juan 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 Juan?
The next few days in San Juan's forecast are the most reliable; accuracy declines beyond about a week as weather-model uncertainty grows.

Climate

San Juan, Texas has a humid subtropical climate: January averages roughly 61°F, July about 86°F, 25°F between them.

Rain and snow bring San Juan roughly 20 inches a year across approximately 155 measurable-precipitation days.

Latitude 26.2°N gives San Juan its 25°F swing, and with it the rhythm of San Juan's growing season.

All cities in Texas →

McAllen, TX weather →

ZIP codes in San Juan

  • 78589

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.