May Weather in San Antonio, United States

Last updated: February 24, 2025

In San Antonio, United States, May brings a delightful mix of warmth and humidity, making it an ideal time to enjoy outdoor activities. The maximum temperature frequently peaks at a scorching 37°C (99°F), while the average settles at a comfortable 25°C (77°F). Nights can be cooler, dipping to a minimum of 11°C (51°F), providing a pleasant respite from the day's heat. Rainfall is a notable feature this month, with 130 mm (5.1 in) spread over approximately 15 days, contributing to an average humidity level of 81%. This combination of factors creates a vibrant atmosphere, perfect for exploring the city's attractions or relaxing in its lush parks.

May Temperature in San Antonio

In May, San Antonio experiences a delightful warming trend that sets the stage for the approaching summer. With temperatures ranging from a minimum of 11°C (51°F) to a maximum of 37°C (99°F), the city enjoys an average temperature of 25°C (77°F), making it an ideal time for outdoor activities. This month marks a noticeable shift from the cooler temps of April, which had an average of 21°C (70°F), helping locals and visitors alike to savor the sunshine and vibrant surroundings. As May progresses, the rising heat hints at the more intense summer days ahead, but the pleasant evenings still offer a refreshing respite. Overall, May serves as a beautiful transition into the hotter months, combining warmth with a hint of summer's promise.

May Weather in San Antonio: Daily Temperature Highs, Lows, and Averages

The chart illustrates May temperature patterns in San Antonio, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends.
JanFebMarAprMayJunJulAugSepOctNovDec525564707782848680716155
Data source: Temperature data for San Antonio generated using information from the Copernicus Climate Change Service.
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The average of daily temperatures (24 hours) calculated across all days in the month.

May Precipitation in San Antonio

In San Antonio, May is a notable month for precipitation, as it receives a striking 130 mm (5.1 in) of rain, making it the wettest month of the year. This month sees an increased frequency of rainfall, with rain occurring on 15 days, contributing significantly to the city’s annual total. The sharp rise in precipitation from April (71 mm or 2.8 in) underscores the transition into the wetter summer season. As temperatures warm up, the abundance of moisture not only supports the lush vegetation typical of this time but also sets the stage for potential thunderstorms. This trend of escalating rainfall in May highlights its crucial role in replenishing local water resources and sustaining the region's vibrant ecosystem.

May Precipitation Trends in San Antonio

The chart displays monthly precipitation patterns in San Antonio, with values for each month alongside May's data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how May's conditions compare to those of other months.
JanFebMarAprMayJunJulAugSepOctNovDec44586271130786956117894657
Data source: Precipitation data for May generated using information from the Copernicus Climate Change Service.
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May Humidity in San Antonio

May in San Antonio marks a noticeable uptick in humidity, rising to 81%, which is among the highest levels of the year. This increase follows the milder conditions of April and precedes the gradual decline during the summer months, peaking in January and December at 79% and 86%, respectively. The trend in San Antonio showcases a pattern of higher humidity in the early months, subsiding as summer approaches, with a striking drop to 66% in July and even lower in August at 58%. As the city transitions into the warmth of late spring, residents can expect a sticky atmosphere before the summer's drier spells set in.

May Average Humidity in San Antonio

This chart illustrates the average monthly humidity levels in San Antonio, with May's data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, allowing you to see how May's humidity levels compare to other months.
JanFebMarAprMayJunJulAugSepOctNovDec79%79%74%76%81%76%66%58%65%74%81%86%
Data source: Humidity data for May generated using information from the Copernicus Climate Change Service.

May UV Index in San Antonio

As spring transitions into summer, the UV Index in San Antonio hits a peak of 11 in May, classifying it under the extreme exposure category with a rapid burn time of just 10 minutes. This trend continues from April, which also featured an extreme index, signaling that outdoor enthusiasts should exercise caution during this period. With UV levels escalating from a moderate 5 in January to an alarming 12 by June, it's essential for residents and visitors alike to stay vigilant. Protect your skin with sunscreen, hats, and protective clothing to safely enjoy the Texas sun. For more detailed information, check the San Antonio UV Index.

Maximum UV Index Levels in San Antonio for May

The chart shows the monthly maximum UV Index (UVI) for San Antonio in May, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues.
JanFebMarAprMayJunJulAugSepOctNovDec589111112121211975
Data source: San Antonio May UVI data generated using information from the Copernicus Climate Change Service.

UV Risk Categories

  •  Extreme (11+): Avoid the sun, stay in shade.
  •  Very High (8-10): Limit sun exposure.
  •  High (6-7): Use SPF 30+ and protective clothing.
  •  Moderate (3-5): Midday shade recommended.
  •  Low (0-2): No protection needed.

May Sunshine in San Antonio

In San Antonio, May shines as a vibrant prelude to summer, basking in an impressive 276 hours of sunshine. This marks a notable increase from the 252 hours enjoyed in April, reflecting the city's transition into a sunnier season. As days lengthen, the warmth fosters a lively atmosphere, setting the stage for outdoor activities and community gatherings. Following May, June peaks with 325 hours of sunlight, indicating a trend where summer months consistently offer an abundance of brightness, with July and August following closely behind. This delightful escalation of sunshine not only enhances the scenic beauty of San Antonio but also invites residents and visitors alike to fully embrace the joys of the outdoors.

Monthly Sunshine Duration in San Antonio: May Highlighted

The May sunshine duration represents the total number of hours San Antonio experiences direct sunlight during the month of May, excluding cloudy or obstructed periods. This chart compares the sunshine duration of May with the other months of the year.
JanFebMarAprMayJunJulAugSepOctNovDec169h162h223h252h276h325h344h330h276h264h223h218h
Data source: San Antonio May Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in San Antonio During May

As we transition into May in San Antonio, the likelihood of sunny weather takes a dip, with only a 34% chance of bright skies. This marks a notable decline from the start of the year, where sunny prospects were more favorable, peaking at 59% in January. Following April’s 40%, May reveals a trend of diminishing sunshine that continues into the sweltering summer months. Interestingly, while June and July also show a 34% chance, September bounces back strongly with 61%, suggesting that as the year progresses, San Antonio's weather fluctuates significantly, promising an intriguing mix of sun and shade throughout the seasons.

Percentage of Sunny Days in May in San Antonio

The chart illustrates the percentage of sunny days in San Antonio throughout the year, with May highlighted. It highlights the variation in sunshine across each month and provides an overview of the typical frequency of sunny days, offering insights into how often San Antonio experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec59%45%49%40%34%44%34%40%61%52%53%37%
Data source: San Antonio May chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in San Antonio in May

As spring transitions into summer, San Antonio experiences a noteworthy increase in daylight duration. In May, the city enjoys 13 hours of daylight, marking a peak that is consistent through June, July, and August. This gradual climb from 10 hours in January to a vibrant 13 hours in May reflects the seasonal shift, as the days grow longer and the sun lingers longer in the sky. Following this bright stretch, daylight begins to recede slightly in September, setting the stage for the shorter days of autumn. The pattern illustrates the gentle ebb and flow of daylight, inviting residents to revel in the warmth and vibrancy of the Texas spring.

Average Daylight Hours in San Antonio for May

The chart illustrates the variation in daylight duration in San Antonio throughout the year, with May highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec10h 29m11h 8m12h12h 53m13h 37m13h 59m13h 47m13h 8m12h 17m11h 24m10h 39m10h 16m
Data source: San Antonio daylight hours, calculated by summing the hours between sunrise and sunset for each day.

May Winds in San Antonio

May in San Antonio brings a gentle breeze, with an average wind speed of 3.6 m/s (8 mph). This slight uptick compared to earlier months like April (3.9 m/s) suggests a refreshing calmness as the city transitions into summer. Interestingly, wind speeds begin to taper off in the following months, reaching the year’s lowest figures in the heart of summer, particularly July and August, where they fall to 2.6 m/s (6 mph). This trend highlights May as a time of moderate wind, offering an invigorating respite while hinting at the stillness that will envelop the coming months. With its mild gusts, May serves as an ideal backdrop for outdoor activities, making the most of the pleasant San Antonio weather before the summer sun fully settles in.

Average May Wind Speed in San Antonio

The chart displays monthly wind speed patterns in San Antonio, with values for each month shown alongside May's data, which is highlighted for easy comparison. It illustrates the average wind speed, offering insights into how May's wind conditions compare to the rest of the year.
JanFebMarAprMayJunJulAugSepOctNovDec3.33.74.03.93.6 m/s3.02.62.62.52.93.02.9
Data source: San Antonio May wind data, generated using information from the Copernicus Climate Change Service.

How May Weather in San Antonio Compares to Other Months

The weather in San Antonio changes throughout the year, offering a unique experience in each season. Below is a month-by-month comparison of May's weather with other months, highlighting differences in temperature, precipitation, and other key factors. Click on each section to discover seasonal trends in San Antonio and find detailed weather information for every month.

May and January present a stark contrast in weather. In May, temperatures range from a minimum of 11°C (51°F) to a scorching maximum of 37°C (99°F), with an average of 25°C (77°F). This month experiences significant rainfall, totaling 130 mm (5.1 in) over about 15 days, alongside high humidity levels at 81%. Conversely, January showcases much colder temperatures, with a minimum of -7°C (20°F) and a maximum of 27°C (81°F), averaging around 11°C (53°F). Precipitation is considerably lower in January, with only 44 mm (1.7 in) over 6 days and humidity sitting at a slightly lower 79%. For more detailed insights, you can check San Antonio weather in January.

May and February present strikingly different weather patterns. In May, temperatures generally range from a minimum of 11°C (51°F) to a scorching maximum of 37°C (99°F), with an average temperature of 25°C (77°F). The month also sees significant rainfall, totaling around 130 mm (5.1 in) over approximately 15 days, accompanied by a high humidity level of 81%. In contrast, February is much cooler, with temperatures dipping as low as -12°C (10°F) and reaching a maximum of 31°C (87°F), while the average temperature hovers around 13°C (55°F). Precipitation is less prevalent during February, amounting to 58 mm (2.3 in) over about 10 days, and humidity remains slightly lower at 79%. For a detailed look at the weather during this month, check out San Antonio weather in February.

In comparing the weather conditions of May and March, we observe significant differences in temperature and precipitation patterns. May offers a much warmer climate with temperatures ranging from a minimum of 11°C (51°F) to a maximum of 37°C (99°F), averaging around 25°C (77°F). In contrast, March experiences cooler temperatures, with a minimum of -3°C (27°F) and a maximum of 33°C (91°F), averaging at 18°C (65°F). Precipitation is also more prevalent in May, with 130 mm (5.1 in) over 15 days, compared to March's 62 mm (2.5 in) over just 9 days. Furthermore, May’s humidity level of 81% surpasses March’s more moderate 74%. For more details, you can visit San Antonio weather in March.

In comparing the weather of May and April, May tends to be significantly warmer and more humid. While April features a minimum temperature of 3°C (37°F) and an average of 21°C (70°F), May sees a much higher minimum of 11°C (51°F) and an average temperature rising to 25°C (77°F). Maximum temperatures also increase, with April reaching a peak of 35°C (95°F) compared to May’s high of 37°C (99°F). Moreover, May experiences approximately double the precipitation of April, with 130 mm (5.1 in) over 15 days, compared to April’s 71 mm (2.8 in) over 8 days. Humidity levels also rise slightly from 76% in April to 81% in May. For more detailed insights, you can view San Antonio weather in April.

In comparing the weather of May and June, we observe a notable increase in average temperatures, with May averaging 25°C (77°F) compared to June's 28°C (83°F). The minimum temperatures also rise significantly, from 11°C (51°F) in May to 18°C (64°F) in June, suggesting warmer nights. Additionally, June experiences slightly more extreme heat, with maximum temperatures reaching up to 39°C (103°F), compared to 37°C (99°F) in May. Precipitation decreases in June to 78 mm (3.1 in) over 12 days, while May sees higher rainfall of 130 mm (5.1 in) over 15 days, leading to a more humid atmosphere in May at 81% compared to June's 76%. For more detailed insights, check out the San Antonio weather in June.

May and July present distinct weather patterns. In May, temperatures range from a minimum of 11°C (51°F) to a maximum of 37°C (99°F), with an average of 25°C (77°F). The month is quite humid, with an average humidity level of 81% and significant rainfall totaling 130 mm (5.1 in) over 15 days. In contrast, July experiences warmer temperatures, with a minimum of 17°C (64°F) and a maximum of 41°C (106°F), averaging 29°C (85°F). The humidity drops to 66%, and precipitation is considerably lower, measuring 69 mm (2.7 in) across 8 days. For a more detailed outlook, you can check San Antonio weather in July.

The weather in May presents a wide temperature range, with minimums around 11°C (51°F) and maximums reaching up to 37°C (99°F), contributing to an average temperature of 25°C (77°F). This month experiences considerable precipitation, with about 130 mm (5.1 in) spread over 15 days, resulting in high humidity levels at 81%. In contrast, August typically features warmer temperatures, with minimums around 20°C (69°F) and maximums soaring to 40°C (103°F), leading to a comfortable average of 30°C (86°F). Moreover, August sees significantly less rainfall, totaling only 56 mm (2.2 in) over just 6 days, alongside lower humidity levels at 58%. For more detailed information, you can check San Antonio weather in August.

May and September present notable differences in weather patterns. In May, temperatures range from a minimum of 11°C (51°F) to a maximum of 37°C (99°F), with an average of 25°C (77°F). This month also sees higher precipitation levels at 130 mm (5.1 in) spread over about 15 days, along with a high humidity of 81%. In contrast, September boasts slightly warmer conditions, with temperatures ranging from a minimum of 12°C (54°F) to a maximum of 39°C (102°F) and an average of 27°C (80°F). Rainfall in September averages 117 mm (4.6 in) over just 10 days, and the humidity drops significantly to 65%. For a deeper dive into weather specifics, you can check out San Antonio weather in September.

In comparing the weather of May and October, we observe notable differences in temperature and precipitation. May features a more significant temperature range, with minimums around 11°C (51°F) and maximums soaring to 37°C (99°F), alongside an average temperature of 25°C (77°F). In contrast, October starts cooler, with minimum temperatures dropping to about 3°C (37°F) and an average of 22°C (72°F), while still reaching highs of 37°C (98°F). Precipitation is more abundant in May with 130 mm (5.1 in) over approximately 15 days, compared to October’s 89 mm (3.5 in) spread across 10 days. Additionally, May sees higher humidity levels at 81%, while October experiences a decrease to 74%. For more detailed insights, you can refer to San Antonio weather in October.

May is characterized by warm and variable temperatures, with a range from a minimum of 11°C (51°F) to a scorching maximum of 37°C (99°F) and an average of 25°C (77°F). This month also sees a significant amount of rainfall, totaling 130 mm (5.1 in) over about 15 days, contributing to the high humidity level of 81%. In contrast, November experiences much cooler weather, starting with minimum temperatures dipping to -4°C (25°F), an average of 16°C (61°F), and a maximum of 32°C (90°F). Precipitation is significantly lower at 46 mm (1.8 in), occurring over just 6 days, while the humidity remains constant at 81%. For more detailed information, you can check out San Antonio weather in November.

May and December present contrasting weather patterns. In May, temperatures soar with a minimum of 11°C (51°F) and an average high reaching 37°C (99°F), accompanied by significant humidity at 81% and frequent precipitation, totaling 130 mm (5.1 in) over 15 days. This makes May typically hot and humid, with a high likelihood of rain. In stark contrast, December experiences cooler temperatures with a minimum of -3°C (27°F) and an average high of 29°C (85°F). The month brings less precipitation, with only 57 mm (2.3 in) over 7 days, along with slightly higher humidity at 86%. For a deeper dive into December's climate specifics, check out San Antonio weather in December.

Compare San Antonio's Climate with Cities Worldwide

Conclusion: What to Expect From May Weather in San Antonio

As May unfolds in San Antonio, the weather transforms into a vibrant tapestry of warmth and humidity, marking a distinct departure from the cooler spring months. With temperatures peaking around 37°C (99°F), the city begins to embrace the summer heat, while the average temperature settles at a pleasant 25°C (77°F). This month is also characterized by increased humidity and rainfall, with about 130 mm (5.1 in) of precipitation over approximately 15 days. So, while May welcomes longer, sunnier days perfect for outdoor adventures, it also signals the start of a more humid climate ahead. To know more about what to expect throughout the year, check out San Antonio Climate.