April weather forecast and climate
San Juan, PR

April, the same as March, is a moderately hot spring month in San Juan, Puerto Rico, with average temperature fluctuating between 81.1°F (27.3°C) and 75.2°F (24°C).

Temperature

In San Juan, the average high-temperature is relatively the same as in March - a still moderately hot 81.1°F (27.3°C). In April, the average low-temperature is 75.2°F (24°C).

Heat index

The average heat index is calculated to a tropical 86.2°F (30.1°C). Exhaustion is likely with prolonged exposure and activity. Sustaining activity may result in heat cramps.
Take into consideration that the heat index values are calculated for shade and light wind conditions. 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 'felt air temperature', 'real feel', 'feels like', or 'apparent temperature', is calculated by taking the relative humidity value for a specific location and factoring it into the air temperature reading. Additional factors like activity, pregnancy, metabolic differences, and wind affect individual temperature impact. Be aware that direct exposure to sunlight increases heat impact, and may raise the heat index additionally, 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.

Humidity

The average relative humidity in April is 77%.

Rainfall

April is the month with the least rainfall. Rain falls for 12.4 days and accumulates 0.55" (14mm) of precipitation.

Ocean temperature

In April, the average ocean temperature in San Juan is 80.4°F (26.9°C).
Note: For swimming, diving, and other water activities, temperatures between 77°F (25°C) and 84.2°F (29°C) are perceived as very enjoyable and pleasurable for prolonged periods without feeling uncomfortable.

Daylight

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

Sunshine

In April, the average sunshine in San Juan, Puerto Rico, is 9.1h.

UV index

Months with the highest UV index in San Juan are April through November, with an average maximum UV index of 7. A UV Index value of 6 to 7 symbolizes a high health hazard from unsafe exposure to the UV radiation for the ordinary person.
Note: The average daily UV index of 7 transform into the following instructions:
Take precautions and adopt sun safety practices. Protection against sunburn is obliged. 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. Beware! The reflection of water and sand dramatically increases exposure to the UV rays.