May weather forecast
Houston, TX

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A beautiful park in Root square overlooking the central business district of Houston, Texas, USA
A beautiful park in Root square overlooking the central business district of Houston, Texas, USA

Weather in May

May brings in the official start of summer in Houston. The city shimmers under the hot sun and becomes bustling with a range of summer activities. May is a festive time in Houston, with several outdoor festivals and concerts that take advantage of the fine weather. Being midway through spring and the onset of summer, May breaks the rainfall record with a whopping 4.45" (113mm). This underlines the typical late spring weather pattern which melds higher humidity with increased rainfall.

Temperature

With the onset of May, Houston's weather sees a minor temperature rise, transitioning from 78.8°F (26°C) in April to a still moderately hot 85.8°F (29.9°C). May brings an average low-temperature of 70°F (21.1°C) to Houston.

Heat index

May's heat index is evaluated at a torrid 96.8°F (36°C). Ensure extra safety steps, heat exhaustion and heat cramps are likely. Long activity might lead to heatstroke.
Regarding the heat index, one should be aware it's determined by shaded settings and mild winds. A direct sunlight exposure may boost the heat index by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'feels like' or 'felt air temperature', represents the fusion of temperature and moisture in the air to suggest how warm it feels. The influence of weather is personal, with varied individuals experiencing it differently due to differences in body mass, stature, and physical exertion levels. When exposed to direct sunlight, it's possible for the heat index to increase by as much as 15 Fahrenheit (8 Celsius) degrees. Heat index values hold particular significance for children. Youngsters often neglect the necessity for rest and hydration. Thirst is a sign of advancing dehydration - thus the importance of maintaining hydration, specifically during long-lasting physical activities.
The human body cools itself through perspiration, as excessive warmth is removed from the body through sweat evaporation. Under conditions of high temperature and humidity (enhanced heat index), sweat production is compromised, exacerbating the sensation of warmth. Increasing body temperatures can be a precursor to dehydration if the body can't shed the extra heat.

Humidity

The average relative humidity in May is 74%.

Rainfall

In Houston, Texas, during May, the rain falls for 14.8 days and regularly aggregates up to 4.45" (113mm) of precipitation. Throughout the year, in Houston, there are 180.5 rainfall days, and 35.35" (898mm) of precipitation is accumulated.

Snowfall

In Houston, snow does not fall in February through November.

Daylight

The average length of the day in May is 13h and 40min.
On the first day of May, sunrise is at 6:38 am and sunset at 7:58 pm. On the last day of the month, sunrise is at 6:21 am and sunset at 8:17 pm CDT.

Sunshine

In May, the average sunshine is 9.3h.

UV index

The months with the highest UV index are May through August, with an average maximum UV index of 7. A UV Index of 6 to 7 symbolizes a high health vulnerability from unsafe exposure to UV radiation for ordinary individuals.
Note: A maximum daily UV index of 7 during May morphs into the following directions:
Skirt overexposure. People with light complexions might get scorched in under 20 minutes. Between 10 a.m. and 4 p.m., UV radiation is strongest. Make an effort to avoid direct sunlight during this time, remembering that shade structures may not provide full sun protection. Clothes that are both tight-knit and comfortably loose are prime choices for sun protection.
Updated: Jul 31, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

How hot is May?

In Houston, in May, the average high-temperature is 85.8°F (29.9°C), and the average low-temperature is 70°F (21.1°C). In May, the average heat index (a.k.a. 'felt air temperature', 'real feel'), which takes the relative humidity and factors it into the air temperature reading, is evaluated at 96.8°F (36°C).

What is the average humidity in May?

In Houston, the average relative humidity in May is 74%.

How much does it rain in May?

In Houston, during May, the rain falls for 14.8 days and regularly aggregates up to 4.45" (113mm) of precipitation.

When it does not snow?

February through November are months without snowfall.

How many hours of daylight does Houston have in May?

In May, the average day length is 13h and 40min.

When are sunrise and sunset in May?

On the first day of May, sunrise is at 6:38 am and sunset at 7:58 pm. On the last day of the month, sunrise is at 6:21 am and sunset at 8:17 pm CDT.

How many hours of sunshine does Houston have in May?

In May, the average sunshine duration is 9.3h.

What are the months with the highest UV index?

May through August, with an average maximum UV index of 7, are months with the highest UV index.

What is the UV index reading in May?

In Houston, the average daily maximum UV index in May is 7. A UV Index reading of 6 to 7 represents a high health threat from unsafe exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in May
Houston, TX

Average temperature in May - Houston, TX
  • Average high temperature in May: 85.8°F

The warmest month (with the highest average high temperature) is August (94.3°F).
The month with the lowest average high temperature is January (61.3°F).

  • Average low temperature in May: 70°F

The month with the highest average low temperature is August (77.5°F).
The coldest month (with the lowest average low temperature) is January (46°F).

Average pressure in May
Houston, TX

Average pressure in May - Houston, TX
  • Average pressure in May: 29.95"Hg

The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).

Average wind speed in May
Houston, TX

Average wind speed in May - Houston, TX
  • Average wind speed in May: 8mph

The windiest month (with the highest average wind speed) is April (8.6mph).
The calmest month (with the lowest average wind speed) is September (5.9mph).

Average humidity in May
Houston, TX

Average humidity in May - Houston, TX
  • Average humidity in May: 74%

The month with the highest relative humidity is February (78%).
The months with the lowest relative humidity are August and October (70%).

Average rainfall in May
Houston, TX

Average rainfall in May - Houston, TX
  • Average rainfall in May: 4.45"

The wettest month (with the highest rainfall) is September (4.49").
The driest month (with the least rainfall) is February (1.77").

Average rainfall days in May
Houston, TX

Average rainfall days in May - Houston, TX
  • Average rainfall days in May: 14.8 days

The month with the highest number of rainy days is September (19.5 days).
The month with the least rainy days is January (11.8 days).

Average snowfall in May
Houston, TX

Average snowfall in May - Houston, TX
  • Average snowfall in May: 0"

The month with the highest snowfall is December (0.08").
The months with the least snowfall are February, March, April, May, June, July, August, September, October and November (0").

Average snowfall days in May
Houston, TX

Average snowfall days in May - Houston, TX
  • Average snowfall days in May: 0 days

The months with the highest number of snowfall days are January and December (0.1 days).
The months with the least snowfall days are February, March, April, May, June, July, August, September, October and November (0 days).

Average daylight in May /
Average sunshine in May
Houston, TX

Average daylight in May / Average sunshine in May - Houston, TX
  • Average daylight in May: 13h and 4min

The month with the longest days is June (Average daylight: 14h and 0min).
The month with the shortest days is December (Average daylight: 10h and 18min).

  • Average sunshine in May: 9h and 2min

The month with the most sunshine is August (Average sunshine: 10h and 30min).
The month with the least sunshine is December (Average sunshine: 4h and 48min).

Average sunshine days in May
Houston, TX

Average sunshine days in May - Houston, TX
  • Average sunshine days in May: 14.2 days

The month with the most sunshine days is January (16.3 days).
The month with the least sunshine days is September (7.9 days).

Average UV index in May
Houston, TX

Average UV index in May - Houston, TX
  • Average UV index in May: 7

The months with the highest UV index are May, June, July and August (UV index 7).
The month with the lowest UV index is December (UV index 3).

Average cloud cover in May
Houston, TX

Average cloud cover in May - Houston, TX
  • Average cloud cover in May: 39

The month with the most cloud cover is February (Cloud cover 51).
The month with the least cloud cover is August (Cloud cover 27).

Average visibility in May
Houston, TX

Average visibility in May - Houston, TX
  • Average visibility in May: 6mi

The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).

Houston, Texas, USA

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