San Juan Temperature by Month

San Juan, North Puerto Rico, Puerto Rico has a consistently comfortable climate year-round, with daytime highs averaging 30°C (86°F). Below you'll find a full monthly breakdown and a comparison with cities worldwide.

San Juan enjoys a stable climate with temperatures staying pretty much the same throughout the year. Maximum daytime temperatures range from a comfortable 28°C (82°F) in January to a very warm 31°C (88°F) in August. Nights are consistently cool, with lows between 25°C (77°F) and 22°C (72°F).

The chart below illustrates the average maximum day and minimum night temperatures in San Juan by month:

From around 4 AM to 6 AM temperatures are at their lowest; by 3 PM they've climbed to their daily peak. August, the warmest month, averages 267 hours of sunshine.

The chart below shows the average temperature throughout the year:

San Juan's average annual maximum temperature is 30°C (86°F). To put that in context, here's how it compares to a few well-known destinations:

Seville, Spain averages 23°C (73°F) a year, one of the warmer cities in Western Europe, with long hot summers.

Interlaken, Switzerland averages 8°C (46°F) a year, with cold winters and cool summers thanks to its Alpine setting.

Osaka, Japan averages 22°C (72°F) annually, with hot humid summers, mild winters, and pleasant spring and autumn seasons.

Tokyo, Japan averages 21°C (70°F) a year, with hot summers, cool winters, and a well-defined cherry blossom spring.

Temperature alone doesn't tell the whole story, humidity plays a big role in how warm or cold it actually feels. High humidity in summer makes the heat feel more intense, particularly once temperatures climb above 25°C. In winter, the same humidity can make cold air feel sharper than the thermometer suggests.

In San Juan, January is the coolest month, with average highs of 28°C (82°F) and humidity around 74%, considered high. In August, the warmest month, temperatures average 31°C (88°F) with 76% humidity, conditions that feel high. For a full picture, see our humidity page.

Climate temperature data is typically calculated as a 30-year average. This smooths out year-to-year variability and gives a more reliable picture of what a place is actually like, rather than what happened in any single unusual year.

The readings come from a range of sources, land-based weather stations, ocean buoys, ships, and satellites. That data is collected by weather services around the world, then pooled, quality-checked, and averaged to produce the climate records you see here.

Global average temperatures have risen by around 1.2°C since the pre-industrial era, and the effects are visible across many regions. Winters are milder on average, with fewer frost days and less snow in many parts of the world. Heatwaves are more frequent and more intense, and Europe's summers of 2018, 2019, and 2020 all set records.

Summers are also getting drier in some areas, while winter rainfall has increased in others. This contributies to higher river levels and more flooding. In many countries, spring arrives earlier and autumn lasts longer. It has knock-on effects for wildlife, agriculture, and local ecosystems.

For more on San Juan's weather, including monthly rainfall, sunshine hours, and humidity, visit our San Juan climate page.