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May Weather in San Juan, Peru

Last updated: August 27, 2025

In May, the average temperature in San Juan, Peru hovers around 12°C (55°F). Expect minimums dipping to 4°C (39°F) and maximums reaching 18°C (65°F). With an average precipitation of 60 mm (2.3 in) over 18 days, be prepared for some wet weather. Don't forget, the air will feel quite humid at an average of 83%!

May Temperature in San Juan

In May in San Juan, the average temperature is 12°C (55°F). Maximums can reach 18°C (65°F), and minimums can be as low as 4°C (39°F). It's a great time for travelers to enjoy mild weather while exploring the area.

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

The chart illustrates May temperature patterns in San Juan, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In San Juan, May typically has an average temperature of 12°C (55°F), with highs reaching up to 18°C (65°F) and lows dropping to around 4°C (39°F).
JanFebMarAprMayJunJulAugSepOctNovDec545555555454555555555555
Data source: Temperature data for San Juan 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 Juan

In San Juan in May, the precipitation amount is 60 mm (2.3 in) over the course of 18 days.

May Precipitation Trends in San Juan

The chart displays monthly precipitation patterns in San Juan, 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. In San Juan, May typically receives around 60 mm (2.3 inches) of precipitation spread over approximately 18 days.
JanFebMarAprMayJunJulAugSepOctNovDec22924424612560231926729976129
Data source: Precipitation data for May generated using information from the Copernicus Climate Change Service.
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May Humidity in San Juan

In San Juan in May humidity is 83%. With an average temperature of 12°C (55°F), this humidity feels like a cool, damp embrace that makes exploring the area both refreshing and slightly uncomfortable, requiring travelers to dress in layers and stay hydrated.

May Average Humidity in San Juan

This chart illustrates the average monthly humidity levels in San Juan, with May’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In May, average humidity in San Juan is approximately 83%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec89%89%90%89%83%69%56%51%53%68%82%87%
Data source: Humidity data for May generated using information from the Copernicus Climate Change Service.

May UV Index in San Juan

In San Juan in May, the maximum UV index is 14, which corresponds to an extreme Exposure Category. The time to burn is just 10 minutes, so it's crucial to take precautions. For the detailed hourly UV index in San Juan, you can check here.

Maximum UV Index Levels in San Juan for May

The chart shows the monthly maximum UV Index (UVI) for San Juan 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. In May, the maximum UV index in San Juan typically reaches 14, which falls under the extreme exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec181918171411131416181818
Data source: San Juan 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.

How May Weather in San Juan Compares to Other Months

Weather in San Juan varies notably across the year, with each month offering distinct climate conditions. This page compares May’s weather to other months in San Juan, focusing on differences in temperature, rainfall, humidity, and UV levels.

This table compares monthly weather conditions in San Juan, showing how May’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather12°C (55°F)229 mm (9.0 inches)89%extreme
February Weather13°C (55°F)244 mm (9.6 inches)89%extreme
March Weather13°C (55°F)246 mm (9.7 inches)90%extreme
April Weather13°C (55°F)125 mm (4.9 inches)89%extreme
May Weather12°C (55°F)60 mm (2.3 inches)83%extreme
June Weather12°C (55°F)23 mm (0.9 inches)69%extreme
July Weather13°C (55°F)19 mm (0.7 inches)56%extreme
August Weather13°C (55°F)26 mm (1.0 inches)50%extreme
September Weather13°C (56°F)72 mm (2.9 inches)53%extreme
October Weather13°C (55°F)99 mm (3.9 inches)68%extreme
November Weather13°C (56°F)76 mm (3.0 inches)81%extreme
December Weather13°C (55°F)129 mm (5.1 inches)87%extreme

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