Frost dates for ZIP 78550 (Harlingen, TX)
Average last spring and first fall frost dates with 10%, 50% and 90% odds, from NOAA's 1991–2020 climate normals for the nearest weather station, Harlingen Rio Grande AP, TX (2 miles away).
Freezes are uncommon here
NOAA's normals for this station show a 32°F night in about 61% of years (about 2 freezing night(s) a year on average). The dates below describe freeze timing for the station's record; in many years there may be no 32°F freeze at all.
- Average last spring frostJan 850% chance of a 32°F freeze after this date
- Average first fall frostDec 2950% chance of a 32°F freeze by this date
- Growing season (frost-free)357 daysmedian, 32°F threshold
- USDA hardiness zone10a30 to 35°F avg. coldest night
Last spring frost odds
| Chance of a 32°F freeze after this date | Date |
|---|---|
| 90% (early: most years still freeze after this) | Dec 12 (prior Dec) |
| 50% (the "average" last frost) | Jan 8 |
| 10% (safe-side: only 1 year in 10 freezes later) | Feb 17 |
Most gardeners plant frost-tender crops (tomatoes, peppers, basil) after the 50% date, and closer to the 10% date for less risk.
First fall frost odds
| Chance the first 32°F freeze has happened by this date | Date |
|---|---|
| 10% (early: 1 year in 10 freezes this soon) | Dec 2 |
| 50% (the "average" first frost) | Dec 29 |
| 90% (late: most years have frozen by now) | Feb 1 (next year) |
Light frost, freeze and hard freeze
| Threshold | Last spring (50%) | First fall (50%) |
|---|---|---|
| 36°F (light frost possible on clear, calm nights) | Jan 31 | Dec 13 |
| 32°F (freeze) | Jan 8 | Dec 29 |
| 28°F (hard freeze) | Jan 2 | Jan 1 (next year) |
n/a means NOAA did not publish a date at that threshold for this station (usually because it rarely gets that cold).
This week in Harlingen
Soil temperature now
2-inch depth
70°F 55°F or warmer
24-hour average · latest 72°F, as of Oct 17, 7:00 PM CDT
Measured at TexMesonet (TWDB) station Russell Farms, 12 mi away. Daily averages: Thu 81°, Fri 78°.
4-inch depth
71°F 55°F or warmer
24-hour average · latest 73°F, as of Oct 17, 7:00 PM CDT
Measured at TexMesonet (TWDB) station Russell Farms, 12 mi away. Daily averages: Thu 82°, Fri 78°.
Fall: Texas A&M AgriLife times fall pre-emergent (for winter weeds such as annual bluegrass) to soil cooling to about 70°F for several days. The 50–55°F band is the spring trigger. Always read and follow the product label.
7-day forecast and frost risk
No frost in the 7-day forecast.
| Period | High | Low | Forecast |
|---|---|---|---|
| Tonight | 56° | Mostly Clear | |
| Sunday | 78° | 63° | Mostly Sunny |
| Monday | 82° | 67° | Chance Rain Showers |
| Tuesday | 86° | 69° | Mostly Sunny then Slight Chance Rain Showers |
| Wednesday | 86° | 68° | Slight Chance Rain Showers then Slight Chance Showers And Thunderstorms |
| Thursday | 86° | 66° | Sunny |
| Friday | 88° | 69° | Sunny |
National Weather Service forecast, issued Oct 17, 8:28 PM CDT. Frost can form above 32°F on clear, calm nights. Full NWS forecast.
Free frost alerts for 78550
An email when the National Weather Service forecasts a freeze for this ZIP, plus the spring soil-temperature heads-up. At most a few a month.
Alerts open soon. This form is a preview and doesn't send anything yet.
Where these numbers come from
Station: Harlingen Rio Grande AP, TX (NOAA GHCN-Daily ID USW00012904), elevation 34 ft, 2.0 miles from the ZIP's center point. NOAA completeness flag: R (representative, 10+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|---|---|---|
| Harlingen, TX | 4 mi | Jan 9 | Jan 3 (next year) |
| Santa Rosa 3 WNW, TX | 13 mi | Jan 10 | Dec 27 |
| Raymondville, TX | 16 mi | Jan 21 | Dec 26 |
The average last-frost dates of these stations span 13 days, a rough guide to local variation. See data sources & methods.
Questions
When is the last frost in 78550?
The average (50% chance) last spring freeze of 32°F for ZIP 78550 is January 8. For a safer planting date, use February 17, when only 1 year in 10 still sees a later freeze.
When is the first frost in 78550?
The average first fall freeze is December 29. In 1 year in 10 it comes by December 2.
What hardiness zone is 78550?
ZIP 78550 is in USDA zone 10a (30 to 35°F average coldest winter night), per the 2023 USDA Plant Hardiness Zone Map ZIP listing.
Other ZIP codes in Cameron County
78520 78521 78526 78535 78552 78559 78566 78567 78575 78578 78583 78586 78592 78593 78597 All Cameron County ZIPs