San Juan
Puerto Rico, USA
Long-term weather forecast
Long-term weather forecast

April weather forecast and climate
San Juan, PR

An old fort building and a view of the stunning San Juan city, Puerto Rico, with a clear view of the calm waterfront
An old fort building and a view of the stunning San Juan city, Puerto Rico, with a clear view of the calm waterfront
April is a tropical spring month in San Juan, Puerto Rico, with temperature in the range of an average high of 86.2°F (30.1°C) and an average low of 74.5°F (23.6°C).

Temperature

In April, the average high-temperature is practically the same as in March - a hot 86.2°F (30.1°C). The average low-temperature, in San Juan, is 74.5°F (23.6°C).

Heat index

The average heat index is evaluated at a very hot 96.1°F (35.6°C). Take special precautions - heat exhaustion and heat cramps are expected. Heatstroke may occur with lengthy activity.
Note that heat index values are valued for light wind and location in the shade. With the exposure to direct sunlight, the heat index may be increased by up to 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'real feel', 'apparent temperature', 'feels like', or 'felt air temperature', is a measure that combines both air temperature and relative humidity into a single value that indicates how hot the weather feels. Additional factors like activity, pregnancy, clothing, and wind affect individual temperature impact. Bear in mind that direct sunshine exposure increases weather impact, and may raise heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are particularly important for children. Children are often less aware of the need to rest and re-hydrate. Thirst is a late sign of dehydration - it is vital to remain hydrated, particularly during prolonged physical activities.
To prevent overheating and help regulate its internal temperature, the human body sweat and rely on the evaporation to cool down. High relative humidity reduces the evaporation rate, resulting in a lower heat removal rate from the body, causing the perception of being overheated. When heat gain surpasses the level the body can shed, body temperature begins to increase, and consequently, overheating and dehydration can occur, with varying severity.

Humidity

In April, the average relative humidity is 71.3%.

Rainfall

In San Juan, Puerto Rico, during 13.3 rainfall days, 4.8" (121mm) of precipitation is typically accumulated. In San Juan, during the entire year, the rain falls for 198.5 days and collects up to 70.6" (1794mm) of precipitation.

Ocean temperature

In San Juan, the average water temperature is 80.4°F (26.9°C).
Note: Water temperature between 77°F (25°C) and 84.2°F (29°C) is regarded as very warm and enjoyable by all. With these temperatures, water activities are pleasurable, without feeling uncomfortable for prolonged periods.

Daylight

The average length of the day in San Juan is 12.6h.

Sunshine

In San Juan, the average sunshine in April is 8.9h.

UV index

Months with the highest UV index are March through September, with an average maximum UV index of 12. A UV Index estimate of 11, and higher, represents an extreme threat to health from unsafe exposure to the UV radiation for the average person.
Note: The average daily UV index of 12 transform into the following instructions:
Take all required precautions, as unprotected skin and eyes can burn in minutes. Seek shade and minimize exposure to direct Sun in a period between 10 a.m. and 4 p.m. when UV radiation is most intense; keep in mind that shade structures like parasols or canopies do not provide perfect sun protection. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes. A broad-spectrum sunscreen of SPF 30+ should be liberally applied and re-applied every two hours, and immediately after an outdoor workout or a swim. Beware! The strength of the UV rays is significantly increased by the reflection of the water and sand.

What is the temperature in April in San Juan?

The average high-temperature, in April, in San Juan, is 86.2°F (30.1°C), while the average low-temperature is 74.5°F (23.6°C). In April, the average heat index (a.k.a. 'real feel', 'feels like'), that represents influence of the relative humidity to air temperaure, is calculated to 96.1°F (35.6°C).

What is the average humidity in April in San Juan?

The average relative humidity in April is 71.3%.

How much does it rain in San Juan in April?

In San Juan, Puerto Rico, in April, it is raining for 13.3 days, with typically 4.8" (121mm) of accumulated precipitation.

How warm is the water in April in San Juan?

In San Juan, in April, the average water temperature is 80.4°F (26.9°C). Water temperature between 77°F (25°C) and 84.2°F (29°C) is regarded as very warm and enjoyable by all. With these temperatures, water activities are pleasurable, without feeling uncomfortable for prolonged periods.

What is the average length of the day in April in San Juan?

In San Juan, the average length of the day in April is 12.6h.

How many hours of sunshine does San Juan have in April?

The average sunshine in April in San Juan is 8.9h.

What is the month with the highest UV index in San Juan?

Months with the highest UV index are March through September, with an average maximum UV index of 12.

What is the UV index reading in April in San Juan?

In April, the average daily maximum UV index in San Juan, Puerto Rico, is 12. A UV Index value of 11, and more, symbolizes an extreme health vulnerability from the exposure to the Sun's UV rays.
Average temperature in April - San Juan, PR
  • Average high temperature in April: 86.2°F

Warmest months (with the highest average high temperature) are August and September (89.2°F).
The month with the lowest average high temperature is January (83.2°F).

  • Average low temperature in April: 74.4°F

The month with the highest average low temperature is August (78.2°F).
Coldest months (with the lowest average low temperature) are January and February (72°F).

Average humidity in April - San Juan, PR
  • Average humidity in April: 71.3%

The month with the highest relative humidity is October (76.9%).
The month with the lowest relative humidity is March (71%).

Average rainfall in April - San Juan, PR
  • Average rainfall in April: 4.8"

The wettest month (with the highest rainfall) is August (7.7").
The driest month (with the lowest rainfall) is March (3.1").

Average rainfall days in April - San Juan, PR
  • Average rainfall days in April: 13.3 days

Months with the highest number of rainy days are November and December (19.6 days).
The month with the lowest number of rainy days is March (12.2 days).

Average sea temperature in April - San Juan, PR
  • Average sea temperature in April: 80.5°F

The best month for swimming (with the highest average sea temperature) is September (84.9°F).
The coldest month (with the lowest average sea temperature) is February (78.9°F).

Average daylight in April / Average sunshine in April - San Juan, PR
  • Average daylight in April: 12.6h

The month with the longest days is June (Average daylight: 13.2h).
The month with shortest days is December (Average daylight: 11h).

  • Average sunshine in April: 8.9h

Months with most sunshine are March and July (Average sunshine: 9.1h).
The month with least sunshine is November (Average sunshine: 6.7h).

Average UV index in April - San Juan, PR
  • Average UV index in April: 12

Months with the highest UV index are March, April, May, June, July, August and September (UV index 12).
Months with the lowest UV index are January and December (UV index 8).