San Juan, Texas Weather
Cicadas claim the scorching afternoon. Day 14 of summer. Read this microseason across nine climate regions →
San Juan weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJul 4Partly Cloudy——98°78°—
- SundayJul 5Overcast——96°77°-2°
- MondayJul 6Overcast——101°78°+5°
- TuesdayJul 7Partly Cloudy——101°78°0°
- WednesdayJul 8Overcast——100°80°-1°
- ThursdayJul 9Overcast——99°79°-1°
- FridayJul 10Overcast——99°80°0°
AQI 24 (Good), driven by PM2.5. AQI flat over the last 6 hours (within ±3 points). PM2.5 at 6.9 µg/m³ (AQI 38), ratio 0.70 with 12 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.
What's driving it
PM × Wind × Precip
PM2.5 at 6.9 µg/m³ (AQI 38), ratio 0.70 with 12 mph wind — characteristic of long-range haze transport rather than a local source.
- PM2.5/PM10
- 0.70
- Wind
- breezy
- 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).








































If the first of July be rainy weather, 'twill rain more or less for four weeks together.
- Moonrise
- 11:11 PM
- Moonset
- 10:53 AM
- In sign
- ♓︎ Pisces
Cicadas claim the scorching afternoon
San Juan at a glance
- Today vs. normal: 85°F — typical for the season
- 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
- Sat98°78°1%
- Sun96°77°2%
- Mon101°78°5%
- Tue101°78°2%
- Wed100°80°1%
- Thu99°79°2%
- Fri99°80°3%
- Sat99°80°5%
- Sun103°79°9%
- Mon101°79°13%
- Tue102°77°9%
- Wed104°79°3%
- Thu107°78°3%
- Fri100°79°2%
- Sat100°81°3%
- Sun101°78°3%
Forecast data from Open-Meteo (CC BY 4.0).
Right now in the garden
Peak growing season
As of July 4, 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.
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 185 of 365 · Wedge 37 of 72
Planting calendar
| Month | Plant | Harvest |
|---|---|---|
| January | — | — |
| February | lettuce, peas, spinach, radishes | — |
| March | lettuce, peas, spinach, radishes, tomatoes, peppers, beans, squash | — |
| April | tomatoes, peppers, beans, squash | — |
| May | tomatoes, peppers, beans, squash | lettuce, peas, radishes |
| June | — | lettuce, peas, radishes |
| July | — | tomatoes, beans, summer squash |
| August | — | tomatoes, beans, summer squash |
| September | — | tomatoes, beans, summer squash |
| October | fall brassicas, garlic (overwinter), carrots | winter squash, tomatoes (last) |
| November | fall 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.
| Month | Mean temp | Precip | Rainy days |
|---|---|---|---|
| January | 61° | 1.2″ | 12 |
| February | 63° | 1.2″ | 12 |
| March | 71° | 1.0″ | 13 |
| April | 76° | 2.0″ | 12 |
| May | 81° | 2.4″ | 16 |
| June | 85° | 1.6″ | 13 |
| July | 86° | 1.7″ | 11 |
| August | 87° | 1.9″ | 13 |
| September | 82° | 2.9″ | 19 |
| October | 77° | 2.3″ | 12 |
| November | 69° | 1.1″ | 11 |
| December | 63° | 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.
ZIP codes in San Juan
- 78589