What is the weather like in San Juan in September?

Expect temperatures between 25°C and 31°C with 45% average rain probability and about 8 hours of sunshine daily.

What is the weather like in San Juan in September?

San Juan in September scores 51/100 based on 30 years of climate data. Worthwhile timing with some trade-offs.

Who should visit San Juan in September?

September in San Juan is ideal for: Business travelers, Adventure seekers.

San Juan Weather in September | 30-Year Forecast

Avg High

31°C

Hottest around day 1

Avg Low

25°C

Coolest around day 29

Rainy Days

30days

45% avg rain chance

Sunshine

8hrs/day

Autumn season

Sea Temperature in September

Atlantic Ocean(Océano Atlántico)

30.1°C

Monthly Average

Water Feel

🌴Tropical

Perfect for swimming and water sports

Swim Rating

✅Excellent for swimming

Based on average sea surface temperature

Body of Water

Atlantic Ocean

Océano Atlántico

San Juan coastline

Essential Travel Info for San Juan

🗓️ Best Time to Visit 📖 Travel Guide 🍴 Food Guide

Currency

USD

$ United States dollar

Language

English

+1 more

Driving

Right side

Travel Intelligence

Exclusive flight analytics & health data for San Juan

Smart Flight Estimator

Airport-to-Airport Logistics

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Flight Connectivity Analysis

Airport traffic data & seasonal patterns

Moderate

52/ 100

Traffic Index

Balanced traffic

Peak Daily Arrivals

slots per day

Peak

Mar

Low

Oct

Monthly Traffic Distribution

183

Jan

197

Feb

216

Mar

190

Apr

203

May

191

Jun

156

Jul

159

Aug

109

Sep

Oct

154

Nov

162

Dec

Traffic Level

Low Season

Key Connections

Orlando (MCO)

Gustavia Gustaf III (SBH)

New York John F Kennedy (JFK)

Miami (MIA)

Fort Lauderdale Hollywood (FLL)

Health & Safety Advisory

CDC travel health recommendations

7 Recommendations

COVID-19

All eligible travelers should be up to date with their COVID-19 vaccines. Please seeYour COVID-19 Vaccinationfor more information.

Hepatitis A

Recommended for unvaccinated travelers one year old or older going to Puerto Rico.Infants 6 to 11 months old should also be vaccinated against Hepatitis A. The dose does not count toward the routine 2-dose series.Travelers allergic to a vaccine component should receive a single dose of immune globulin, which provides effective protection for up to 2 months depending on dosage given.Unvaccinated travelers who are over 40 years old, are immunocompromised, or have chronic medical conditions planning to depart to a risk area in less than 2 weeks should get the initial dose of vaccine and at the same appointment receive immune globulin.

Hepatitis B

Recommended for unvaccinated travelers of all ages traveling to Puerto Rico.

Measles

Cases of measles are on the rise worldwide. Travelers are at risk of measles if they have not been fully vaccinated at least two weeks prior to departure, or have not had measles in the past, and travel internationally to areas where measles is spreading.All international travelers should be fully vaccinated against measles with the measles-mumps-rubella (MMR) vaccine, including an early dose for infants 6–11 months, according toCDC’s measles vaccination recommendations for international travel.

Rabies

Dogs infected with rabies are not commonly found in Puerto Rico.Rabies is commonly found in some terrestrial wildlife species and bats.If rabies exposures occur while in Puerto Rico, rabies vaccines are typically available throughout most of the country.Rabies pre-exposure vaccination considerations include whether travelers 1) will be performing occupational or recreational activities that increase risk for exposure to potentially rabid animals and 2) might have difficulty getting prompt access to safe post-exposure prophylaxis.Please consult with a healthcare provider to determine whether you should receive pre-exposure vaccination before travel.For more information, seecountry rabies status assessments.

Typhoid

Recommended for most travelers, especially those staying with friends or relatives or visiting smaller cities or rural areas.

+1 more

Source: CDC Travelers' Health

View Complete Health Guide

Is September a Good Time to Visit San Juan?

👌Worthwhile timing with some trade-offs(51/100)

Short Answer

⚠️ September falls in San Juan's typhoon season. While daily weather averages 31°C with 45% rain, tropical storms can disrupt travel. Flexible bookings recommended.

Decision Factors

Atlantic Hurricane season active

Atlantic zone - expect potential atlantic hurricane activity

Oppressive heat and humidity

31°C with 81% humidity - challenging conditions

Vaccinations required

Yellow Fever

Feels significantly hotter than 31°C

Heat index: 41°C due to 81% humidity

Warm tropical seas

30.1°C sea temperature - Hot Soup

Frequent rainfall expected

45% chance of rain - pack waterproofs

Good For

💼
Business travelers
Climate-controlled meetings unaffected by weather
🎯
Adventure seekers
1.19m waves - good for surfing and water sports

Who Should Avoid

👨‍👩‍👧‍👦
Families with children
41°C heat index dangerous for children
👴
Elderly travelers
Heat index of 41°C poses health risks
🥾
Outdoor enthusiasts
Extreme conditions limit outdoor activity options
💼
Business travelers
Storm season may cause flight disruptions

"According to 30YearWeather's analysis of 30 years of NASA POWER satellite data,San Juan in September averages 31°C with 45% precipitation probability."

📊 Source: 30YearWeather.com🛰️ Data: NASA POWER (1991-2021)View Methodology →

Frequently Asked Questions: San Juan in September

What are the temperatures in San Juan in September?

Daytime highs average 31°C, nights drop to 25°C. Temperatures remain fairly consistent.

How many rainy days in San Juan in September?

Expect around 30 days with measurable rainfall. An umbrella is advisable.

What to wear in San Juan in September?

Light, breathable fabrics. Don't forget sunglasses and a hat.

Is September peak season in San Juan?

This is shoulder season—moderate prices and manageable crowds.

San Juan Weather in September