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January Weather in San Isidro, Puerto Rico

Last updated: August 31, 2025

In January, the average temperature in San Isidro, Puerto Rico is a pleasant 25°C (77°F). You'll experience a comfortable range, with minimum temperatures dipping to 21°C (69°F) and highs reaching up to 29°C (85°F). Be prepared for some rain, as 38 mm (1.5 in) of precipitation is expected over 12 days, accompanied by an average humidity of 76%.

January Temperature in San Isidro

In January in San Isidro, the average temperature is 25°C (77°F), with maximums reaching 29°C (85°F) and minimums dropping to 21°C (69°F). This pleasant weather makes it an ideal time for outdoor activities and exploring the local attractions.

January Weather in San Isidro: Daily Temperature Highs, Lows, and Averages

The chart illustrates January temperature patterns in San Isidro, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In San Isidro, January typically has an average temperature of 25°C (77°F), with highs reaching up to 29°C (85°F) and lows dropping to around 21°C (69°F).
JanFebMarAprMayJunJulAugSepOctNovDec777677788081828282817978
Data source: Temperature data for San Isidro 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.

January Precipitation in San Isidro

In San Isidro in January, the precipitation amount is 38 mm (1.5 in) over the course of 12 days.

January Precipitation Trends in San Isidro

The chart displays monthly precipitation patterns in San Isidro, with values for each month alongside January’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how January’s conditions compare to those of other months. In San Isidro, January typically receives around 38 mm (1.5 inches) of precipitation spread over approximately 12 days.
JanFebMarAprMayJunJulAugSepOctNovDec394367566468879917314510651
Data source: Precipitation data for January generated using information from the Copernicus Climate Change Service.
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January Humidity in San Isidro

In San Isidro in January, humidity is 76%. With an average temperature of 25°C (77°F), this humidity feels like a warm, heavy blanket wrapping around you, making traveling feel muggy and requiring frequent breaks to stay refreshed.

January Average Humidity in San Isidro

This chart illustrates the average monthly humidity levels in San Isidro, with January’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In January, average humidity in San Isidro is approximately 76%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec76%75%74%75%75%77%80%80%79%78%78%76%
Data source: Humidity data for January generated using information from the Copernicus Climate Change Service.

January UV Index in San Isidro

In San Isidro in January, the maximum UV index is 9, which corresponds to a very high Exposure Category. The time to burn is just 15 minutes, so it's essential to take precautions. For detailed information, you can check the Hourly UV Index in San Isidro.

Maximum UV Index Levels in San Isidro for January

The chart shows the monthly maximum UV Index (UVI) for San Isidro in January, 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 January, the maximum UV index in San Isidro typically reaches 9, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec911131314131213131298
Data source: San Isidro January 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 January Weather in San Isidro Compares to Other Months

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

This table compares monthly weather conditions in San Isidro, showing how January’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather25°C (77°F)38 mm (1.5 inches)76%very high
February Weather25°C (77°F)43 mm (1.7 inches)75%extreme
March Weather25°C (77°F)67 mm (2.6 inches)74%extreme
April Weather26°C (78°F)56 mm (2.2 inches)75%extreme
May Weather27°C (80°F)64 mm (2.5 inches)75%extreme
June Weather27°C (81°F)68 mm (2.7 inches)77%extreme
July Weather28°C (82°F)87 mm (3.4 inches)80%extreme
August Weather28°C (82°F)99 mm (3.9 inches)80%extreme
September Weather28°C (82°F)173 mm (6.8 inches)79%extreme
October Weather27°C (81°F)145 mm (5.7 inches)78%extreme
November Weather26°C (80°F)106 mm (4.2 inches)78%very high
December Weather26°C (78°F)51 mm (2.0 inches)76%very high

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