May Weather in San Marcos, United States

Last updated: February 24, 2025

In San Marcos, United States, May brings a diverse climate characterized by warm temperatures and notable humidity. With a maximum soaring to 36°C (98°F) and an average of 25°C (76°F), residents experience balmy days interspersed with cooler nights, dipping down to a minimum of 10°C (51°F). This month also sees frequent precipitation, totaling 149 mm (5.9 inches) across approximately 14 days, enhancing the region's vibrant greenery. A relative humidity of 81% pervades the air, creating a moist environment that underscores the lush beauty and vitality of May in San Marcos.

May Temperature in San Marcos

In May, San Marcos, United States, begins to embrace the warmth of summer with temperatures rising significantly. The month opens with a minimum temperature of 10°C (51°F), which is a marked increase from the cooler spring months. As the days progress, the average temperature climbs to a pleasant 25°C (76°F), creating ideal conditions for outdoor activities. The peak temperature reaches 36°C (98°F), hinting at the approaching heat of summer. Overall, May serves as a transitional period, showcasing a steady upward trend in warmth as residents prepare for the hotter months ahead. With the increase in temperatures, May not only invites longer days but also provides a vibrant backdrop for spring adventures.

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

The chart illustrates May temperature patterns in San Marcos, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends.
JanFebMarAprMayJunJulAugSepOctNovDec525363687681848579706055
Data source: Temperature data for San Marcos generated using information from the Copernicus Climate Change Service.
Choose your preferred temperature unit
The average of daily temperatures (24 hours) calculated across all days in the month.

May Precipitation in San Marcos

In May, San Marcos experiences a notable shift in its weather patterns, marked by a significant increase in precipitation. With 149 mm (5.9 in) of rainfall over 14 days, May stands out as the wettest month of the year, highlighting a trend of intensifying spring showers. This dramatic rise from 89 mm in April demonstrates how spring transitions to early summer can bring heavier rainfall, providing vital moisture for local vegetation and ecosystems. As temperatures rise and the region gears up for summer, these May downpours play a crucial role in sustaining the lush greenery that defines San Marcos, setting the stage for a vibrant growing season.

May Precipitation Trends in San Marcos

The chart displays monthly precipitation patterns in San Marcos, 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.
JanFebMarAprMayJunJulAugSepOctNovDec4860678914910280111112944973
Data source: Precipitation data for May generated using information from the Copernicus Climate Change Service.
Choose your preferred precipitation unit

May Humidity in San Marcos

As spring transitions into summer, May in San Marcos experiences a notable increase in humidity, reaching an average of 81%. This slight uptick builds on the earlier months, with January and February also holding steady at 79%, suggesting that residents may start feeling the warmth coupled with a bit more moisture in the air. Following the lively blooms of April, which has a humidity of 76%, May’s elevated levels herald the onset of the warmer months ahead. Interestingly, this is contrasted by the subsequent drop in humidity during the summer, particularly in July and August, where levels decrease to 66% and 58%, respectively. This cycle of humidity not only influences the weather but also affects the local flora and outdoor activities, marking May as a pivotal month in the humid narrative of San Marcos.

May Average Humidity in San Marcos

This chart illustrates the average monthly humidity levels in San Marcos, 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 Marcos

As the days warm up in May, San Marcos experiences an extreme UV Index of 11, maintaining the same intensity seen in April. With a burn time of just 10 minutes, this month serves as a critical reminder for sun safety. The trend indicates a gradual increase in UV exposure from January's moderate UV Index of 5 to the current extreme levels, highlighting the need for precautions as we transition into hotter months. This high index will persist into June, suggesting a consistent call for protection against harmful rays. To learn more about the UV Index and how to stay safe under the sun, visit San Marcos UV Index.

Maximum UV Index Levels in San Marcos for May

The chart shows the monthly maximum UV Index (UVI) for San Marcos 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.
JanFebMarAprMayJunJulAugSepOctNovDec589111112121211965
Data source: San Marcos 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 Marcos

May in San Marcos is a radiant transition into summer, boasting an impressive 282 hours of sunshine. This month marks a significant peak compared to the earlier spring months, with April's 260 hours leading up to it. As the days grow longer and warmer, San Marcos experiences a consistent upward trend in sunlight, especially from March onward. The sunshine only intensifies as summer approaches, with June reaching a remarkable 329 hours. This pattern not only invites outdoor activities but also highlights the region's appeal as a vibrant destination for sun-seekers, making May a delightful prelude to the sun-soaked months ahead.

Monthly Sunshine Duration in San Marcos: May Highlighted

The May sunshine duration represents the total number of hours San Marcos 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.
JanFebMarAprMayJunJulAugSepOctNovDec170h165h229h260h282h329h348h329h277h270h230h223h
Data source: San Marcos May Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in San Marcos During May

As May rolls around in San Marcos, the chance of sunny weather dips to 29%, marking a significant decline from the sunnier months earlier in the year. Following a peak in January at 58%, the overall trend showcases a gradual decrease in sunny days leading into late spring, reaching some of the lowest probabilities of the year. This pattern suggests that while May may bring some overcast skies, the promise of clearer conditions returns in the summer, with 42% likelihood in June and fluctuating sunlit days throughout the subsequent months. Thus, those planning to enjoy outdoor activities should be mindful of the weather's unpredictable nature in May, balancing their hopes for sun with the reality of its reduced likelihood.

Percentage of Sunny Days in May in San Marcos

The chart illustrates the percentage of sunny days in San Marcos 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 Marcos experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec58%44%50%41%29%42%31%37%59%52%57%37%
Data source: San Marcos May chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in San Marcos in May

As spring unfolds in San Marcos, the length of daylight gradually increases, peaking in May with 13 hours of sunlight. Following a steady rise from 10 hours in January to 12 hours in March and April, May marks a delightful transition where the vibrant colors of blooming flowers and lush greenery are illuminated by abundant daylight. This trend continues into June, where daylight reaches its apex at 14 hours. However, as summer wanes, the daylight duration begins to taper off again, returning to 12 hours in September and gradually decreasing until it levels out at 10 hours by December. This rhythmic pattern of daylight not only influences the city’s natural beauty but also shapes the activities and moods of its residents.

Average Daylight Hours in San Marcos for May

The chart illustrates the variation in daylight duration in San Marcos throughout the year, with May highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec10h 26m11h 7m12h12h 54m13h 40m14h 2m13h 50m13h 9m12h 17m11h 23m10h 37m10h 13m
Data source: San Marcos daylight hours, calculated by summing the hours between sunrise and sunset for each day.

May Winds in San Marcos

In San Marcos, the month of May presents a slight dip in wind speed, with an average of 3.6 m/s (8 mph), continuing a trend of moderate breezes experienced in the spring months. Following a gradual increase from 3.4 m/s in January to 4.1 m/s in March, the winds stabilize in April before softening in May. As summer approaches, wind speeds further decline into the warmer months, indicating a shift towards a calmer atmosphere. Notably, while May remains one of the more breezy months of the season, it does set the stage for the lighter winds of June and July, where speeds fall below 3 m/s, reflecting a general easing of the air movement as the year progresses.

Average May Wind Speed in San Marcos

The chart displays monthly wind speed patterns in San Marcos, 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.
JanFebMarAprMayJunJulAugSepOctNovDec3.43.94.13.93.6 m/s2.92.52.72.53.13.23.4
Data source: San Marcos May wind data, generated using information from the Copernicus Climate Change Service.

How May Weather in San Marcos Compares to Other Months

The weather in San Marcos 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 Marcos and find detailed weather information for every month.

When comparing the weather in May and January, it's clear that May brings much warmer temperatures, with averages around 25°C (76°F) and highs reaching up to 36°C (98°F). In contrast, January experiences much cooler conditions, with average temperatures of 11°C (52°F) and minimal highs of 26°C (80°F). Additionally, May tends to have more precipitation, recorded at 149 mm (5.9 in) over 14 days, whereas January sees only 48 mm (1.9 in) over 6 days. Humidity levels are quite similar, with May at 81% and January at 79%. For more details on January weather, visit San Marcos weather in January.

In comparing the weather between May and February, notable differences emerge. May boasts a significantly warmer temperature range, with minimums of 10°C (51°F) advancing to maximums of 36°C (98°F) and an average of 25°C (76°F). In contrast, February experiences much colder temperatures, ranging from a minimum of -15°C (6°F) to a maximum of 31°C (87°F) and an average of 12°C (54°F). Precipitation levels also diverge, as May receives 149 mm (5.9 in) over 14 days, while February sees only 60 mm (2.4 in) across 10 days. Humidity levels are comparable, with May at 81% and February slightly lower at 79%. For more detailed information, check out San Marcos weather in February.

In comparing the weather of May and March, we see some notable differences. May tends to be significantly warmer, with average temperatures reaching 25°C (76°F) and maximums soaring to 36°C (98°F), while March has cooler average temperatures of 17°C (64°F) and maximums of 33°C (91°F). Additionally, May experiences a higher level of humidity at 81% compared to March's 74%. Though both months see a fair amount of rainfall, May has more precipitation at 149 mm (5.9 in) over 14 days, whereas March has 67 mm (2.6 in) over 11 days. For a closer look at March's weather specifically, check out San Marcos weather in March.

In May, the weather significantly warms up compared to April, with minimum temperatures rising from 3°C (38°F) in April to 10°C (51°F) in May. The average temperature also shows an increase, moving from 20°C (69°F) in April to a warm 25°C (76°F) in May, reaching a maximum of 36°C (98°F). Additionally, May experiences more precipitation, with 149 mm (5.9 in) of rain over 14 days, compared to April's 89 mm (3.5 in) over just 9 days. The humidity levels also increase slightly from 76% in April to 81% in May, contributing to a more muggy atmosphere. For more detailed information about April weather, you can visit San Marcos weather in April.

In comparing the weather between May and June, May tends to be cooler with average temperatures ranging from a low of 10°C (51°F) to a high of 36°C (98°F), whereas June shows a slightly warmer average with temperatures between 17°C (63°F) and 37°C (100°F). Additionally, May experiences higher precipitation levels at 149 mm (5.9 in) over 14 days, contributing to a humidity of 81%. In contrast, June has less rainfall, totaling 102 mm (4.0 in) over 12 days, resulting in a lower humidity of 76%. This transition indicates a shift towards drier and warmer conditions as summer progresses. For more details, you can check San Marcos weather in June.

May and July present distinct weather patterns in terms of temperature and precipitation. In May, temperatures range from a minimum of 10°C (51°F) to a scorching maximum of 36°C (98°F), with an average temperature of 25°C (76°F). The month experiences significant precipitation, totaling 149 mm (5.9 in) over about 14 days, accompanied by high humidity levels of 81%.

In contrast, July sees warmer temperatures, with a minimum of 17°C (63°F) and a maximum reaching up to 41°C (106°F), averaging 29°C (84°F). Rainfall is considerably lower in July, with only 79 mm (3.1 in) spread over 9 days, and humidity drops to a more comfortable 66%. This shift in weather emphasizes July's hotter and drier conditions compared to the cooler and wetter month of May. For a detailed look at July's weather, visit San Marcos weather in July.

May and August exhibit notable differences in weather patterns. In May, temperatures range from a cool 10°C (51°F) to a warm 36°C (98°F), with an average of 25°C (76°F). The month is characterized by high humidity at 81% and significant precipitation, averaging 149 mm (5.9 in) over 14 days. In contrast, August presents a warmer climate with minimum temperatures of 20°C (68°F) and maximums reaching up to 40°C (104°F), averaging 29°C (85°F). This month sees lower humidity levels at 58% and less rainfall, totaling 111 mm (4.4 in) over just 7 days. For more details on August weather, you can check San Marcos weather in August.

In May, temperatures typically range from a minimum of 10°C (51°F) to a maximum of 36°C (98°F), with an average temperature of 25°C (76°F). The month sees significant precipitation, averaging 149 mm (5.9 in) over 14 days, contributing to a high humidity level of 81%. In contrast, September experiences a slightly warmer average temperature of 26°C (79°F), with maximum temperatures reaching up to 38°C (100°F). Precipitation decreases to 112 mm (4.4 in) over 11 days, and humidity drops to a more comfortable 65%. This shift in weather makes September more stable and less humid compared to May. For more detailed insights about September weather, you can visit San Marcos weather in September.

In May, the weather is significantly warmer and more humid compared to October, with temperatures ranging from a minimum of 10°C (51°F) to a maximum of 36°C (98°F) and an average of 25°C (76°F). The month sees considerable rainfall, averaging 149 mm (5.9 in) over 14 days, resulting in a humidity level of 81%. In contrast, October experiences cooler temperatures, with a minimum of 3°C (37°F), an average of 21°C (70°F), and a maximum of 35°C (96°F). Rainfall is less frequent, totaling around 94 mm (3.7 in) across 10 days, and humidity decreases to 74%. For more details, you can check out San Marcos weather in October.

May and November present contrasting yet intriguing weather patterns. In May, temperatures soar with a range from a minimum of 10°C (51°F) to a scorching maximum of 36°C (98°F), accompanied by significant precipitation totaling 149 mm (5.9 in) over 14 days, which contributes to a high humidity level of 81%. In stark contrast, November experiences much cooler temperatures, ranging from a minimum of -3°C (26°F) to a pleasant average of 15°C (60°F) and a maximum of 30°C (86°F). The precipitation is considerably less in November, at 49 mm (1.9 in) across just 6 days, with humidity remaining steady at 81%. For more details about November's climate in San Marcos, you can visit San Marcos weather in November.

In May, temperatures can range from a refreshing 10°C (51°F) at night to a scorching 36°C (98°F) during the day, with an average of 25°C (76°F). The month experiences significant rainfall, totaling 149 mm (5.9 in) over about 14 days, accompanied by high humidity levels of 81%. In contrast, December offers a much cooler climate, with temperatures dipping to a minimum of -3°C (27°F) and reaching a maximum of 29°C (84°F), averaging around 13°C (55°F). Precipitation is also lower, with 73 mm (2.9 in) spread across just 7 days, while humidity remains relatively high at 86%. For more specifics on the December weather, you can explore San Marcos weather in December.

Compare San Marcos's Climate with Cities Worldwide

Conclusion: What to Expect From May Weather in San Marcos

May in San Marcos is characterized by a noticeable shift in weather, as the region warms up with significantly higher temperatures compared to earlier spring months. While the average temperature reaches a comfortable 25°C (76°F), the peak can soar to an impressive 36°C (98°F), making outdoor activities increasingly appealing. However, this month also ushers in a higher humidity level at 81%, contributing to a more tropical feel. Rainfall becomes more frequent, with 14 days receiving 149 mm (5.9 in) of precipitation, indicating a transition toward the wetter summer months. Overall, May presents a vibrant blend of warmth and moisture, setting the stage for the summer ahead. For a deeper dive into what to expect throughout the year, check out San Marcos Climate.