Climate - Harlingen (Texas)

The climate of Harlingen is sub-tropical, with a very mild winter (but with the possibility of short cold spells) and a very hot, muggy summer.
The city is located in the southern tip of Texas, near the Mexican border, and 50 km (30 mi) away from the coast.
We are on the 26th parallel, not far from the Tropic, and indeed the hot season is very long.
The winter, from December to February, is very mild.
The sun shines quite often, although there are periods characterized by clouds, rain and wind.
There may be warm periods even in the middle of winter, with highs around 25 °C (77 °F) and more, sometimes even 30 °C (86 °F).
However, there may also be brief cold periods, with highs below 10 °C (50 °F). Very rarely, as happened on Christmas 2004, in December 2017 and in February 2021, it can even snow. In recent decades, the record is -8 °C (17.5 °F), recorded in December 1989. In February 2021, the temperature reached -5.5 °C (22 °F).
The summer, from June to September, is very hot and sunny, with some thunderstorms. There combination of humidity and temperature makes the heat sweltering.
There can be long, very hot periods even in May and October, and sometimes in late April, while for short periods, the temperature can reach about 40 °C (104 °F) from March to September. The record is 42 °C (107.5 °F), last recorded in early September 2000.
From June to November (but with a higher probability from August to October), there is the risk of hurricanes. The city was hit hard by Hurricane Dolly in late July 2008.
The average temperature of the coldest month (January) is of 16 °C (61 °F), that of the warmest month (August) is of 30.1 °C (86 °F). Here are the average temperatures.

Precipitation amounts to 610 millimeters (24 inches) per year. It ranges from 20 mm (0.8 in) in the driest month (February) to 135 mm (5.3 in) in the wettest (September). We are in the westernmost part, the driest of the Texan coast. Here is the average precipitation.

On average, there are around 2,750 sunshine hours per year. So the city is sunny. Here are the average sunshine hours per day.

The sea temperature ranges between 20 °C (68 °F) and 29 °C (84 °F). From January to March, the sea is very cool, while it becomes pleasantly warm for swimming from June to October. Here are the average sea temperatures.

Best Time

The best time to visit Harlingen is from November to March. Winter, from December to February, is generally a mild season, although it can sometimes get cold (especially in December and January). You can therefore choose the months of March and November.

Return to the climate of Texas.

Harlingen - Weather by month

Based on the period 1991-2020

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In January, the coldest month of the year, the weather in Harlingen is usually very mild. The average temperature is of 16.0 °C (61 °F), with a minimum of 9.9 °C (49.8 °F) and a maximum of 22.1 °C (71.7 °F).
On the coldest nights of the month, the temperature usually drops to around 1.5 °C (34.5 °F). However, it dropped to -4 °C (24.8 °F) in January 2010.
On the warmest days of the month, the temperature usually reaches around 29.5 °C (85 °F). However, it reached 34.4 °C (93.9 °F) in January 2002.
Precipitation amounts to 25 mm (1 in), distributed over 8 days.
The day lasts on average 10 hours and 40 minutes.
There are on average 4.5 hours of sunshine per day. So, the sun shines 43% of the time.
The average humidity is 74%. Hence, the air is normally humid.
The average wind speed is 18 kph (11 mph).
The average sea temperature is of 20.5 °C (69 °F). Therefore, the sea is cool for swimming.

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In February, the weather in Harlingen is usually warm. The average temperature is of 18.3 °C (65 °F), with a minimum of 12.2 °C (53.9 °F) and a maximum of 24.4 °C (75.9 °F).
On the coldest nights of the month, the temperature usually drops to around 3.5 °C (38 °F). However, it dropped to -3 °C (26.6 °F) in February 2011.
On the warmest days of the month, the temperature usually reaches around 31.5 °C (88.5 °F). However, it reached 35.6 °C (96.1 °F) in February 2017.
Precipitation amounts to 20 mm (0.8 in), distributed over 6 days.
The day lasts on average 11 hours and 20 minutes.
There are on average 5.5 hours of sunshine per day. So, the sun shines 50% of the time.
The average humidity is 74%. Hence, the air is normally humid.
The average wind speed is 20 kph (12 mph).
The average sea temperature is of 20 °C (67.5 °F). Therefore, the sea is very cool for swimming.

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In March, the weather in Harlingen is usually warm. The average temperature is of 21.2 °C (70 °F), with a minimum of 15.2 °C (59.4 °F) and a maximum of 27.2 °C (81 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around 5.5 °C (41.5 °F). However, it dropped to -2.3 °C (27.9 °F) in March 1996.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 34 °C (93.5 °F). However, it reached 38.3 °C (100.9 °F) in March 2009.
Precipitation amounts to 35 mm (1.4 in), distributed over 6 days.
The day lasts on average 12 hours and 0 minutes.
There are on average 7 hours of sunshine per day. So, the sun shines 57% of the time.
The average humidity is 71%. Hence, the air is normally humid.
The average wind speed is 21 kph (13 mph).
The average sea temperature is of 20 °C (68.5 °F). Therefore, the sea is very cool for swimming.

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In April, the weather in Harlingen is usually warm to hot and muggy. The average temperature is of 24.4 °C (76 °F), with a minimum of 18.4 °C (65.2 °F) and a maximum of 30.3 °C (86.5 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around 9.5 °C (49 °F). However, it dropped to 5 °C (41 °F) in April 2007.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 35.5 °C (96.5 °F). However, it reached 40 °C (104 °F) in April 2017.
Precipitation amounts to 35 mm (1.4 in), distributed over 5 days.
The day lasts on average 12 hours and 50 minutes.
There are on average 7.5 hours of sunshine per day. So, the sun shines 59% of the time.
The average humidity is 71%. Hence, the air is normally humid.
The average wind speed is 21 kph (13 mph).
The average sea temperature is of 22 °C (72 °F). Therefore, the sea is cool for swimming.

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In May, the weather in Harlingen is usually warm to hot and muggy. The average temperature is of 27.3 °C (81 °F), with a minimum of 21.7 °C (71 °F) and a maximum of 33 °C (91.4 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around 15 °C (59 °F). However, it dropped to 10 °C (50 °F) in May 2004.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 36 °C (97 °F). However, it reached 39.4 °C (102.9 °F) in May 1999.
Precipitation amounts to 65 mm (2.6 in), distributed over 6 days.
The day lasts on average 13 hours and 30 minutes.
There are on average 8.5 hours of sunshine per day. So, the sun shines 62% of the time.
The average humidity is 73%. Hence, the air is normally humid.
The average wind speed is 20 kph (13 mph).
The average sea temperature is of 25 °C (77.5 °F). Therefore, the sea is warm enough for swimming.

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In June, the weather in Harlingen is usually very hot and muggy. The average temperature is of 29.3 °C (85 °F), with a minimum of 23.7 °C (74.6 °F) and a maximum of 35 °C (95 °F).
On the coldest nights, the temperature usually drops to around 20.5 °C (68.5 °F). However, it dropped to 16 °C (60.8 °F) in June 1997.
On the warmest days, the temperature usually reaches around 37.5 °C (99.5 °F). However, it reached 41.7 °C (107.1 °F) in June 2019.
Precipitation amounts to 55 mm (2.2 in), distributed over 6 days.
The day lasts on average 13 hours and 50 minutes. June 21, the summer solstice, is the longest day of the year in the Northern Hemisphere.
There are on average 10 hours of sunshine per day. So, the sun shines 74% of the time.
The average humidity is 72%. Hence, the air is normally humid.
The average wind speed is 19 kph (12 mph).
The average sea temperature is of 28 °C (82 °F). Therefore, the sea is pleasantly warm and allows long swims.

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In July, the weather in Harlingen is usually very hot. The average temperature is of 29.9 °C (86 °F), with a minimum of 24.1 °C (75.3 °F) and a maximum of 35.7 °C (96.2 °F).
On the coldest nights of the month, the temperature usually drops to around 21.5 °C (71 °F). However, it dropped to 18.8 °C (65.8 °F) in July 1993.
On the warmest days of the month, the temperature usually reaches around 38.5 °C (101 °F). However, it reached 40 °C (104 °F) in July 2003.
Precipitation amounts to 45 mm (1.8 in), distributed over 6 days.
The day lasts on average 13 hours and 35 minutes.
There are on average 11 hours of sunshine per day. So, the sun shines 80% of the time.
The average humidity is 70%.
The average wind speed is 19 kph (12 mph).
The average sea temperature is of 28.5 °C (83 °F). Therefore, the sea is pleasantly warm and allows long swims.

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In August, the warmest month of the year, the weather in Harlingen is usually very hot. The average temperature is of 30.1 °C (86 °F), with a minimum of 24.1 °C (75.3 °F) and a maximum of 36.2 °C (97.2 °F).
On the coldest nights of the month, the temperature usually drops to around 22 °C (71.5 °F). However, it dropped to 20 °C (68 °F) in August 1999.
On the warmest days of the month, the temperature usually reaches around 38.5 °C (101.5 °F). However, it reached 41.1 °C (106 °F) in August 2011.
Precipitation amounts to 50 mm (2 in), distributed over 5 days.
The day lasts on average 13 hours and 0 minutes.
There are on average 10 hours of sunshine per day. So, the sun shines 77% of the time.
The average humidity is 69%.
The average wind speed is 17 kph (10 mph).
The average sea temperature is of 29 °C (84 °F). Therefore, the sea is pleasantly warm and allows long swims.

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In September, the weather in Harlingen is usually very hot and muggy. The average temperature is of 28.0 °C (82 °F), with a minimum of 22.5 °C (72.5 °F) and a maximum of 33.4 °C (92.2 °F).
On the coldest nights, the temperature usually drops to around 17.5 °C (63.5 °F). However, it dropped to 11.7 °C (53.1 °F) in September 2000.
On the warmest days, the temperature usually reaches around 37 °C (98.5 °F). However, it reached 42 °C (107.6 °F) in September 2000.
Precipitation amounts to 135 mm (5.3 in), distributed over 11 days.
The day lasts on average 12 hours and 20 minutes.
There are on average 8.5 hours of sunshine per day. So, the sun shines 68% of the time.
The average humidity is 76%. Hence, the air is normally humid.
The average wind speed is 14 kph (9 mph).
The average sea temperature is of 29 °C (84 °F). Therefore, the sea is pleasantly warm and allows long swims.

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In October, the weather in Harlingen is usually warm to hot and muggy. The average temperature is of 24.8 °C (77 °F), with a minimum of 18.7 °C (65.6 °F) and a maximum of 30.9 °C (87.6 °F).
On the coldest nights, which normally occur at the end of the month, the temperature usually drops to around 9.5 °C (49.5 °F). However, it dropped to -0.6 °C (30.9 °F) in October 1993.
On the warmest days, which normally occur at the beginning of the month, the temperature usually reaches around 35 °C (94.5 °F). However, it reached 38.3 °C (100.9 °F) in October 2012.
Precipitation amounts to 70 mm (2.8 in), distributed over 9 days.
The day lasts on average 11 hours and 30 minutes.
There are on average 7.5 hours of sunshine per day. So, the sun shines 65% of the time.
The average humidity is 74%. Hence, the air is normally humid.
The average wind speed is 16 kph (10 mph).
The average sea temperature is of 27 °C (81 °F). Therefore, the sea is pleasantly warm and allows long swims.

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In November, the weather in Harlingen is usually warm. The average temperature is of 20.2 °C (68 °F), with a minimum of 14.1 °C (57.4 °F) and a maximum of 26.3 °C (79.3 °F).
On the coldest nights, which normally occur at the end of the month, the temperature usually drops to around 4.5 °C (40.5 °F). However, it dropped to -0.6 °C (30.9 °F) in November 2018.
On the warmest days, which normally occur at the beginning of the month, the temperature usually reaches around 32.5 °C (90 °F). However, it reached 38.9 °C (102 °F) in November 2013.
Precipitation amounts to 45 mm (1.8 in), distributed over 8 days.
The day lasts on average 10 hours and 50 minutes.
There are on average 6 hours of sunshine per day. So, the sun shines 54% of the time.
The average humidity is 74%. Hence, the air is normally humid.
The average wind speed is 17 kph (10 mph).
The average sea temperature is of 24.5 °C (76 °F). Therefore, the sea is warm enough for swimming.

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In December, the weather in Harlingen is usually very mild. The average temperature is of 16.9 °C (62 °F), with a minimum of 10.9 °C (51.6 °F) and a maximum of 22.9 °C (73.2 °F).
On the coldest nights of the month, the temperature usually drops to around 1.5 °C (34.5 °F). However, it dropped to -4 °C (24.8 °F) in December 1996.
On the warmest days of the month, the temperature usually reaches around 30 °C (86 °F). However, it reached 33 °C (91.4 °F) in December 1996.
Precipitation amounts to 30 mm (1.2 in), distributed over 8 days.
The day lasts on average 10 hours and 30 minutes. December 21, the winter solstice, is the shortest day of the year in the Northern Hemisphere.
There are on average 4.5 hours of sunshine per day. So, the sun shines 43% of the time.
The average humidity is 74%. Hence, the air is normally humid.
The average wind speed is 18 kph (11 mph).
The average sea temperature is of 22 °C (72 °F). Therefore, the sea is cool for swimming.