Harlingen climate — normals and trends
Harlingen (United States) has a hot semi-arid climate (BSh) under the Köppen-Geiger classification. Its mean annual temperature is 23.5 °C and it receives 581 mm of precipitation per year.
These figures are normals computed over 86 complete calendar years, from 1940 to 2025, using ERA5 reanalysis data from the Copernicus programme.
The warmest month is July (29.4 °C on average) and the coldest is January (15.9 °C). Rainfall peaks in September.
Harlingen averages 1 frost days, 181 hot days (≥ 30 °C) and 91 rainy days per year.
Harlingen has warmed by +1.1 °C between 1940 and 2025, or +0.13 °C per decade. This trend is statistically significant.
The hottest day of the period reached 42.1 °C (on 5 September 2000) and the coldest -8.0 °C (on 23 December 1989).
Data from ERA5 reanalysis (Copernicus Climate Change Service), redistributed under a CC-BY 4.0 licence. Normals are recomputed whenever the archive is updated.
Climate normals · ERA5
HarlingenTexas
- coords
- 26.19°, -97.70°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
23.5°C
Average daily high
28.8°C
Average daily low
19.3°C
Annual rainfall
581mm
Sunshine / day
10.0h
Mean relative humidity
72%
Average peak wind
24.2km/h
Seasonal range
13.5°C
Frost days (< 0 °C)
1 d/yr
Hot days (≥ 30 °C)
181 d/yr
Rainy days (≥ 1 mm)
91 d/yr
Annual snowfall
0.1 cm
Average feels-like high
29.8 °C
Average feels-like low
20.2 °C
Average peak gust
42.8 km/h
Tropical nights (≥ 20 °C)
203 d/yr
Solar radiation
17.8 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+1.1 °C
since 1940
+0.1 °C per decade · r² = 0.26 · p = < 0.001
Trend fitted by linear regression (ordinary least squares) on annual means. A trend is shown only when it is statistically significant (p < 0.05).
A climograph overlays rainfall (bars) and temperature (line): the standard reading in climatology, where you can see at a glance whether the warm season is also the dry one.
Records for the period
Hottest day
42.1 °C
5 September 2000
Coldest day
-8.0 °C
23 December 1989
Wettest day
187 mm
23 July 2008
Windiest day
79.8 km/h
20 September 1967
Strongest gust
137.5 km/h
9 August 1980
Hottest feels-like
49.9 °C
9 May 2024
Coldest feels-like
-15.5 °C
25 December 1983
Snowiest day
5.4 cm
25 December 2004
Sunniest day
13.0 h
30 April 1940
Normals computed over complete calendar years 1940–2025.
A specific year
Pick a year and see how it compares to normal — warmer, drier or more extreme than usual?
Across the whole year
Month by month
| High | vs. normal | Precipitation | vs. normal | |
|---|---|---|---|---|
| Jan | 19.5 °C | -1.8 °C | 27 mm | -7 mm |
| Feb | 24.5 °C | +1.3 °C | 5 mm | -27 mm |
| Mar | 29.9 °C | +3.6 °C | 60 mm | +25 mm |
| Apr | 30.5 °C | +1.1 °C | 8 mm | -36 mm |
| May | 33.0 °C | +1.2 °C | 90 mm | +38 mm |
| Jun | 34.3 °C | +0.5 °C | 70 mm | +15 mm |
| Jul | 35.0 °C | +0.2 °C | 33 mm | -17 mm |
| Aug | 36.3 °C | +1.4 °C | 56 mm | -1 mm |
| Sep | 33.4 °C | +1.1 °C | 115 mm | +18 mm |
| Oct | 32.6 °C | +3.0 °C | 18 mm | -39 mm |
| Nov | 29.5 °C | +4.0 °C | 21 mm | -15 mm |
| Dec | 24.9 °C | +2.4 °C | 24 mm | -8 mm |
The year's extremes
What was the weather like that day?
Your birthday, a wedding, a memorable trip: discover the actual weather for any date since 1940.
Frequently asked questions
What is the climate of Harlingen?
Harlingen has a hot semi-arid climate (Köppen BSh). Over 1940-2025, the average annual temperature is 23.5 °C and it receives 581 mm of precipitation per year.
What is the hottest day ever recorded in Harlingen?
The hottest day measured in Harlingen between 1940 and 2025 was 5 September 2000, reaching 42.1 °C.
What is the coldest day in Harlingen?
The coldest day measured in Harlingen between 1940 and 2025 was 23 December 1989, at -8.0 °C.
Does it snow in Harlingen?
Almost never: Harlingen sees virtually no snow, with about 1 frost days per year.
Has the climate of Harlingen warmed?
Yes: Harlingen warmed by +1.1 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Harlingen?
The wettest day measured in Harlingen between 1940 and 2025 was 23 July 2008, with 187 mm of rain in 24 hours.
What was the windiest day in Harlingen?
The windiest day measured in Harlingen between 1940 and 2025 was 20 September 1967, with winds reaching 79.8 km/h.
What is the warmest month in Harlingen?
The warmest month in Harlingen is July (29.4 °C on average); the coldest is January (15.9 °C).
How much does it rain in Harlingen?
Harlingen receives on average 581 mm of precipitation per year, spread over about 91 rainy days.
Is it sunny in Harlingen?
Harlingen gets on average 10.0 hours of sunshine per day, roughly 3,650 hours per year over 1940-2025.
What is the biggest single-day snowfall in Harlingen?
The heaviest 24-hour snowfall measured in Harlingen between 1940 and 2025 was 25 December 2004, with 5.4 cm.
Are there tropical nights in Harlingen?
Yes: Harlingen has on average 203 tropical nights per year (temperature staying above 20 °C), over 1940-2025.
What was the most extreme apparent temperature in Harlingen?
In Harlingen, between 1940 and 2025, the highest apparent temperature reached 49.9 °C on 9 May 2024, and the lowest was -15.5 °C on 25 December 1983.
Compare Harlingen with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Harlingen