July weather forecast
San Juan, PR

July continues the summer heat in San Juan with the year's highest average high temperature of 84.2°F (29°C). Interestingly, the month also sees the year's maximum wind speed at a moderate 10.7mph (17.2km/h). The sea temperature swings to a comfortable 83.6°F (28.7°C) fostering waterside activities. Despite increased cloud cover, sunshine hours remain relatively high. These elements augment the essence of a vibrant Caribbean summer in the city.

Temperature

The transition into July notes an average high-temperature of a still warm 84.2°F (29°C), matching June's climate closely. July is characterized by a steady nighttime low-temperature of 78.8°F (26°C).

Heat index

Throughout July, the heat index is estimated at a very hot 95°F (35°C). More protective measures are required - heat exhaustion and heat cramps are likely. Heatstroke may follow lengthy activity.
Be advised, the heat index considers values for conditions in shade and with a light breeze. Exposure to direct sunshine can increase heat index values by up to 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'real feel' or 'felt air temperature', measures the perceived warmth when incorporating the humidity present in the air. The influence of weather is personal, differing among individuals based on variations in body mass, stature, and the degree of physical exertion. One must note that being under the direct sun can escalate the heat's effects, with the heat index possibly rising by 15 Fahrenheit (8 Celsius) degrees. Heat index values hold great significance to children. Children often do not understand the need to rest and hydrate. Thirst is a late manifestation of dehydration - therefore, it is essential to stay hydrated, particularly during prolonged physical activities.
Humans rely on perspiration as a cooling mechanism, wherein the evaporating sweat counteracts excessive warmth. An increase in relative humidity retards evaporation, subsequently reducing the body's heat removal rate and leading to a sensation of being overly warm. As the body gains more heat than it can dissipate, there's a risk of increasing temperatures and resultant overheating.

Humidity

The months with the highest humidity are May through July, with an average relative humidity of 79%.

Rainfall

In San Juan, in July, during 13.3 rainfall days, 1.1" (28mm) of precipitation is typically accumulated. Throughout the year, there are 159.9 rainfall days, and 12.01" (305mm) of precipitation is accumulated.

Ocean temperature

In July, the average ocean temperature is 83.7°F (28.7°C).
Note: Ideal surface water temperatures for any water activity fall between 77°F (25°C) and 84.2°F (29°C), offering maximum enjoyment for lengthened periods.

Daylight

The average length of the day in July is 13h and 7min.
On the first day of July, sunrise is at 5:51 am and sunset at 7:05 pm. On the last day of the month, sunrise is at 6:02 am and sunset at 6:59 pm AST.

Sunshine

In San Juan, Puerto Rico, the average sunshine in July is 10.2h.

UV index

The months with the highest UV index in San Juan are April through November, with an average maximum UV index of 7. A UV Index of 6 to 7 symbolizes a high health hazard from unprotected exposure to Sun's UV rays for average individuals.
Note: The maximum daily UV index of 7 in July converts into the following recommendations:
Steer clear of overexposure. Fair-skinned individuals can be scorched in less than 20 minutes. Try to minimize direct Sun exposure between 10 a.m. and 4 p.m., the peak period for UV radiation. Also note that objects like parasols or canopies might not provide complete sun protection. A wide-brimmed hat is a shield, deflecting up to 50% of harmful UV radiation from eyes. Beware! The reflection of water and sand dramatically increases exposure to the UV rays.