Frost dates for Harlingen Rio Grande Airport, TX
At Harlingen Rio Grande Airport, the median last spring frost (32°F) is Jan 8 and the median first fall frost is Dec 29, for a typical growing season of 357 days. For a 90% chance that the last frost has passed, wait until Feb 17. Nearby ZIP codes are in USDA hardiness zone 10a.
- Jan 8Last spring frost (median)50% chance of 32°F after this date
- Feb 17Safer planting date10% chance of 32°F after this date
- Dec 29First fall frost (median)50% chance of 32°F by this date
- 357 daysGrowing season (median)between 32°F freezes
Last spring frost dates
The chance that the temperature drops to the threshold after each date.
| Temperature | 90% chance later | 50% chance later | 10% chance later |
|---|---|---|---|
| 36°F | Dec 28 | Jan 31 | Mar 3 |
| 32°F | Dec 12 | Jan 8 | Feb 17 |
| 28°F | Dec 14 | Jan 2 | Feb 1 |
First fall frost dates
The chance that the temperature has dropped to the threshold by each date.
| Temperature | 10% chance by | 50% chance by | 90% chance by |
|---|---|---|---|
| 36°F | Nov 18 | Dec 13 | Jan 15 |
| 32°F | Dec 2 | Dec 29 | Feb 1 |
| 28°F | Dec 13 | Jan 1 | Jan 28 |
Growing season length
Days between the last spring and first fall freeze, as the length reached in 9, 5 and 1 out of 10 years.
| Temperature | 9 in 10 years at least | 5 in 10 years at least | 1 in 10 years at least |
|---|---|---|---|
| 36°F | 279 days | 318 days | 357 days |
| 32°F | 314 days | 357 days | 365 days |
| 28°F | 354 days | 365 days | 365 days |
| 24°F | 365 days | 365 days | 365 days |
Chance of a freeze in any year
| Temperature | Chance per year |
|---|---|
| 36°F | 96% |
| 32°F | 61% |
| 28°F | 18% |
| 24°F | 2% |
ZIP codes whose closest station is this one
| ZIP | Hardiness zone | Avg. extreme low | Distance |
|---|---|---|---|
| 78550 | 10a | 30 to 35°F | 3 km |
Not the official USDA Plant Hardiness Zone Map. Zones shown here are the values published in the USDA-ARS / Oregon State University PRISM Group 2023 ZIP code tables, shown unaltered. For the official interactive map, visit planthardiness.ars.usda.gov.
About this station
- NOAA station ID USW00012904, at 26.2281, -97.6542, elevation 10 m (34 ft).
- Data quality: Representative (10+ years), 23 years of freeze data.
- Average days per year at or below 32°F: 2.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Harlingen (3 km)
- Santa Rosa 3 WNW (22 km)
- Raymondville (29 km)
- Port Isabel Cameron Airport (32 km)
- Weslaco (32 km)
- Port Isabel (37 km)
- WFO Brownsville (42 km)
- Brownsville (42 km)
Sources
- NOAA National Centers for Environmental Information, U.S. Climate Normals 1991–2020, annual/seasonal normals by station (version 1.0.1), file dated June 27, 2023; documentation.
- USDA Agricultural Research Service and PRISM Group, Oregon State University, 2023 Plant Hardiness Zone Map ZIP code tables (CONUS, Alaska, Hawaii, Puerto Rico), files dated November 17, 2023. Data © PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed November 1, 2026. Official map: planthardiness.ars.usda.gov.
- U.S. Census Bureau, 2024 Gazetteer ZIP Code Tabulation Areas file, dated August 30, 2024 (ZIP centroids used to find the nearest station).
Freeze dates are 30-year probabilities, not forecasts. Check your local forecast before planting tender plants.