May Weather in Harlingen, Texas - 2026

The city of Harlingen is located in Cameron County, in the central region of the Rio Grande Valley, Texas. The city is located at 30 Miles (48 km) from the Gulf of Mexico. It is known as a major transport and distribution hub for cotton, citrus fruit, and vegetables of the lower Rio Grande Valley. It is surrounded by chemical and other industries on the outskirts. The climate of the town is tropical all year-round and the snowbirds can surely have a memorable visit because of all the resorting amenities offered by the town along with the weather and lifestyle of Harlingen.

Weather May 2026 in Harlingen Texas:

Generally, May in Harlingen will be quite hot, with an average temperature of around 91°F / 33°C. But due to the extreme humidity it can feel extremely uncomfortable. You can expect around 6 rainy days, with on average 0.7 inches / 18 mm of rain during the month of May.
Very uncomfortable (very high humidity) with high temperatures
Eric Friedebach - CC BY 3.0

May weather in Harlingen Texas

To get a good overview of the type of weather you can expect in May in Harlingen, we will look at the day and night temperature, minimum and maximum water temperature, and if May is comfortable or humid

Generally, May in Harlingen will be quite hot. Historical data shows that you can expect an average temperature of around 91°F / 33°C. But due to the extreme humidity it can feel extremely uncomfortable. During the night, it will cool down to around 71°F / 22°C. Many will prefer a location with air conditioning due to the high humidity level.

Harlingen has some rainy days in May. You can expect around 6 rainy days, with on average 0.7 inches / 18 mm of rain during the whole month.

Average temperature
Average Sea temperature
Wintersun Comfort grade and huricane risk

The forecast for May 2026 is based on historical data and are averages. They will give a good indication what you can expect, but the daily temperature and rain will fluctuate during the month.

May weather in Harlingen Texas in more detail

To get a better feeling for the type of weather, you can expect in May in Harlingen, we will look at the temperature, rain, wind, humidity, water temperature, and sun and clouds

- What will the temperature be in Harlingen in May

Generally, you can expect in May an average temperature of 91°F / 33°C during the day and an average of 71°F / 22°C during the night. In May, during the warmest part of the afternoon, the temperature can often get as high as 98°F / 37°C, and at the end of the night, it can get as low as 60°F / 16°C.

When looking at the whole year, January is the coldest month, with an average temperature of around 71°F / 22°C. August is the hottest month, with an average temperature of around 95°F / 35°C. When comparing May with the temperature in the month before and after, this is slightly higher than April, which sees an average maximum temperature of around 86°F / 30°C. And almost equal to June, which sees an average maximum temperature of around 93°F / 34°C.

Day and night temperature variation for Harlingen during the year.
Day and night temperature variation for Harlingen during the year.

But average temperatures only tell half of the story. It is also good to check the maximum and minimum temperatures. When looking at the whole year, June and August are the hottest months, with a temperature of around 100°F / 38°C. January is the coldest month, with a temperature of around 84°F / 29°C. When comparing May with the temperature in the month before and after, this is almost equal to April, which sees an average maximum temperature of around 96°F / 36°C. And almost equal to June, which sees an average maximum temperature of around 100°F / 38°C.

In the following graph, you can see how many cold and hot days you can expect in Harlingen each month:

Day and night temperature variation for Harlingen during the year.
Day and night temperature variation for Harlingen during the year.

- Can you expect rain in May in Harlingen?

Generally, you can expect about 6 rain days in May, with on average 0.7 inches / 18 mm of rain.

When looking at the whole year, March is the dryest month, with an average rainfall of around 0.7 inches / 17 mmmm. September is the wettest month, with an average rainfall of around 2 inches / 50 mmmm. When comparing May with the month before and after, this is slightly less than April, which sees around 0.8 inches / 21 mm of rain. And less than June, which sees around 0.9 inches / 24 mm of rain

Rain days for Harlingen during the year.
Rain days for Harlingen during the year.

If we look at the number of days with rain, March is the month with the least amount of rain days with around 6 days. September is the month with the most rain days with around 11 days. When comparing May with the month before and after, this is almost equal to April, which sees around 6 days of rain. And almost equal to June, which sees an average of between 6 and 7 days of rain

- What will the water temperature be in Harlingen for May

You can expect in May, the water temperature for Harlingen to be between 82°F / 28°C and 73°F / 23°C.

To compare the water temperature we will use the maximum water temperature. You can expect this temperature on a more sunny day, close to the shore, when the wind does not mix the relatively warmer and colder water.

September has the highest water temperature, with around 87°F / 31°C. February has the lowest water temperature, with around 66°F / 19°C. When comparing the water temperature from May with the month before and after, May has a water temperature almost equal to April, with a water temperature of around 78°F / 26°C. And slightly less than the water temperature from June, that is around 86°F / 30°C.

Water temperature for Harlingen during the year.
Water temperature for Harlingen during the year.

- Can you expect in May a lot of sunny days in Harlingen

Generally, you can expect around 5 sunny days in May and around 25 partly sunny days. The remaining days will be cloudy.

When looking at the whole year, August is the month with the highest number of sunny days, with an average of between 17 and 18 sunny days. April is the month with the lowest number of sunny days, with an average of between 4 and 5 sunny days. When comparing May with the number of sunny days in the month before and after, it is almost equal to April, with an average of between 4 and 5 sunny days. And less than June, with an average of between 10 and 11 sunny days

The number of sunny, partly sunny, and cloudy days for Harlingen
The number of sunny, partly sunny, and cloudy days for Harlingen

We have looked at the sunny days in Harlingen. Let's also look at the cloudy or overcast days. January is the month with the highest number of cloudy days, with around 10 cloudy days. August is the month with the lowest number of cloudy days, with an average of between 1 and 2 cloudy days. When comparing May with the number of cloudy days in the month before and after, it is slightly lower than April, with an average of between 4 and 5 cloudy days. And almost equal to June, with an average of between 1 and 2 cloudy days

- Will it be comfortable in May in Harlingen?

Generally, May in Harlingen will be extremely humid, and can feel extremely uncomfortable.

We use the humidity and temperature in Harlingen to calculate the Wintersun Expert Comfort level for each month. The lower the Wintersun Expert Comfort level, the more comfortable it will be. Only for certain people, extremely dry air can feel slightly uncomfortable.

When looking at the whole year, November has the lowest humidity, with a Wintersun Expert comfort level of "very comfortable" (dry air). July has the highest humidity, with a Wintersun Expert comfort level of "very uncomfortable" (very high humidity). When comparing May with the month before and after, this is almost equal to April, which has a Wintersun Comfort level of "very uncomfortable" (very high humidity). And almost equal to June, which has a Wintersun Comfort level of "extremely uncomfortable" (extremely humid)

Wintersun Expert Humidity / Comfort level for Harlingen
Wintersun Expert Humidity / Comfort level for Harlingen

What to do in Harlingen Texas in May

Harlingen is a popular tourist location. There are many places that you can visit in the area. Some of these include:

  • The Harlingen Heritage & Arts Museum: The museum houses the eminent collection of Harlingen and Texas historic objects and photos. The main museum building features rotating arts and cultural exhibits. The building was the original home of the founder of Harlingen "Lon .C. Hill" and the first hospital of Harlingen. The building was used as an Air Force base as well.
  • Iwo Jima Monument: Visit the monument to honor the Marines of the historic Iwo Jima Battle in WWII, the statue features six Marines raising the US flag to mark the victory of the battle. You can attend the Veterans Day Parade held in November and the Iwo Jima Parade scheduled in February as well. You can also visit the Iwo Jima Gift Shop for souvenirs.
  • Lower Rio Grande Valley National Wildlife Refuge: It is home to 1200 species of native plants, 700 species of vertebrates, and 300 species of butterflies. You can get a chance to see the rare ocelot, Mexican bluewing butterfly, Northern caracara, and lots more. You can visit this place for hiking, taking pictures of the majestic views and wildlife, hunting, fishing, and interpretive programs.
  • La Feria Nature Center: The Park is lit with trails, playgrounds, picnic pavilions, observation decks for bird watching, and a butterfly garden.
  • Arroyo Park: You can visit the park for picnics, hiking, fishing, nature sightseeing as well as bird watching. Go to the Raptor Ridge for serene views of the mountains and enjoy a snack on the spot.

Is it humid in Harlingen Texas in May?

A lot of people ask interested in the humidity or relative humidity for Harlingen Texas in May. But the real question they want to ask is not about humidity but the amount of moisture in the air. Or better, about comfort. Will it be comfortable in May in Harlingen, or will high humidity make it uncomfortable.

To answer this question, we have to look at the dew point. Relative humidity can change a lot in Harlingen during the day and night, as it changes when the amount of moisture changes and, but also when the temperature changes. It is a lot less reliable for comfort. Where the dew point only varies with the amount of moisture in the air.

Looking at the dew point, we can see that for the month of May, you can expect that Harlingen will be extremely humid, and can feel extremely uncomfortable.

November is the month with the most comfort. It will have a low humidty, and will feel very comfortable. July is the most uncomfortable month. It will be extremely humid, and can feel extremely uncomfortable. In the graph, you can see that there is a significant difference between the most comfortable and most uncomfortable months

Humidity level for Harlingen
Humidity level for Harlingen

Is May a good time to go to Harlingen Texas?

Trying to answer the question of whether May is a good time to go to Harlingen is not as easy as it first seems. Some people like colder weather, and others prefer a warmer climate. Some are fine with some humidity, and others are not. If your location has air conditioning, the night temperature is less important.

These are some examples. I will try to answer the question with a more generic person in mind. The more detailed information in this article should be enough to check further if this applies to you as well.

If we look at the average temperature for Harlingen in May, we can see that it will be too hot for a lot of visitors. In May, you can expect it to be quite hot, with an average temperature of around 91°F / 33°C. But due to the extreme humidity it can feel extremely uncomfortable. During the night, it will be around 71°F / 22°C.

As the number of overcast days is not high, you can enjoy the sun with around 5 sunny days and 25 partly sunny days.

The last aspect we will look at is rain. You can expect around 6 rainy days, with on average 0.7 inches / 18 mm of rain during May. More then 5 days rain per month makes the chance higher you will see some rain during a shorter stay. But a day with rain does not mean a day you can not enjoy.

We have looked at the average day temperature, the night temperature, humidity, the number of overcast days, and the rain. We think that May in Harlingen Texas is not the most optimal destination. But that doesn't mean it is not a good time for you to go. As said before, each visitor has their own preferences when it comes to the weather.

Does it rain all day in Harlingen Texas in May?

In Harlingen, it does not rain all day in May. You can expect around 6 rainy days, with on average 0.7 inches / 18 mm of rain during the month.

Another way of looking at the rain is the number of sunny days. For Harlingen Texas, there are, on average 5 sunny days and 25 partly sunny days in May. That clearly shows that it is not raining all the time.

Is May the rainiest month in Harlingen Texas?

May is not the month with the most rainy days, and not the month with the most rain.

To answer what the rainiest month is in Harlingen, we will both look at the month with the most rain, and the month with the highest number of rainy days.

September is the month with the the highest number of rainiest days. On average, you can expect 11 days with rain. March is the month with the lowest number of rainy days, with aproximately 6 days.

September is the month with the most rain. This is not equal as the one with the most rainy days. On average, you can expect 2 inches / 50 mm of rain. March is the month with the least amount of rain. This is not the same month as the one with the lowest number of rainy days. You can expect approximately 0.7 inches / 17 mm of rain.

Is May the most sunniest month in Harlingen Texas?

May is not the month with the most sunny days, it is the month with the most partly sunny days, and it is not the month with the lowest number of overcast days.

To answer what the sunniest month is in Harlingen, we will of course look at the month with the most sunniest days, but also look at the month with the biggest number of days that are sunny or partly sunny.

August is the month with the highest number of sunny days. On average, you can expect 5 sunny days, and 25 partly suny days. April is the month with the lowest number of sunny days.

August is the month with the highest number of sunny days and partly sunny days combined. While February is the month with the lowest number of sunny days and partly sunny days combined.

The last thing we will look at is the number of overcast days. August is the month with the lowest number of overcast days. While January is the month with the highest number of overcast days.

More information about Harlingen Texas

Weather in Harlingen Texas in other months

What to do in Harlingen Texas for each month

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