San Juan, TX Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for San Juan, a community in Starr County, Texas.
Today
102°F
Sunny
Sunny, with a high near 102. Heat index values as high as 111. Southeast wind 7 to 12 mph, with gusts as high as 23 mph.
7-day forecast for San Juan
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 102°F | Sunny | 7 to 12 mph SE | 2% |
| Tonight | 79°F | Partly Cloudy | 8 to 12 mph SE | 3% |
| Wednesday | 102°F | Mostly Sunny | 7 to 10 mph SE | 1% |
| Wednesday Night | 79°F | Mostly Clear | 7 to 12 mph SE | 0% |
| Thursday | 103°F | Sunny | 6 to 10 mph SE | 4% |
| Thursday Night | 78°F | Mostly Clear | 6 to 12 mph SE | 4% |
| Friday | 102°F | Sunny | 5 to 9 mph SE | 2% |
| Friday Night | 77°F | Mostly Clear | 5 to 10 mph SE | 2% |
| Saturday | 101°F | Sunny | 3 to 8 mph ESE | 1% |
| Saturday Night | 78°F | Mostly Clear | 3 to 10 mph SE | 1% |
| Sunday | 102°F | Sunny | 3 to 9 mph SE | 3% |
| Sunday Night | 79°F | Mostly Clear | 7 to 10 mph SE | 3% |
| Monday | 103°F | Sunny | 6 to 12 mph SE | 2% |
| Monday Night | 79°F | Mostly Clear | 13 mph SE | 2% |
Forecast source: National Weather Service (api.weather.gov) for San Juan (26.415, -98.944). Updated through the day.
Growing snapshot for San Juan
Last spring frost
Jan 9
First fall frost
Jan 1
Growing season
363 days
Hardiness zone
9b
More local growing data for San Juan: nearby ZIP 78585 weather · frost dates · planting calendar · Texas frost dates
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Falcon Heights
Climate data from the nearest NOAA station, Falcon Dam, Tx (6.2 mi from San Juan). Frost dates are 1991–2020 averages, not a forecast. Page updated Aug 4, 2026.