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Weather Comparison

Santo Domingo vs San Juan

Side-by-side weather comparison for September

Santo Domingo: 30°CSan Juan: 31°C403 km apart

September Weather: Santo Domingo vs San Juan

MetricSanto DomingoSan JuanBetter
Average HighHigher is warmer30°C (86°F)31°C (88°F)San Juan
Average LowHigher is milder23°C (73°F)25°C (77°F)San Juan
Rain DaysFewer is drier21 days21 daysTie
PrecipitationLess is drier127 mm128 mmSanto Domingo
Sunshine HoursMore is sunnier10h/day11h/daySan Juan
HumidityLower is more comfortable78%78%Tie
UV IndexLower is safer66Tie
Wind SpeedCalmer is better12 km/h18 km/hSanto Domingo

Which City is Better in September?

Based on sunshine hours, rain days, comfortable temperatures, and humidity levels, San Juan edges ahead as the better destination in September. San Juan offers 11 hours of daily sunshine with only 21 rain days, while Santo Domingo sees 10 sunshine hours and 21 rain days.

Santo Domingo can feel quite hot at 30°C, so plan for heat. San Juan runs hot at 31°C.

For travelers who prioritize dry weather, both cities are equally dry in September. San Juan receives 1 more hour of sunshine per day, which matters for sightseeing and outdoor activities.

Temperature Comparison in September

Santo Domingo reaches an average high of 30°C (86°F) and drops to 23°C (73°F) at night during September. The daily temperature range is 7°C, meaning relatively stable temperatures from day to night.

San Juan averages 31°C (88°F) for the high and 25°C (77°F) for the low, with a daily range of 6°C. The two cities feel quite similar in terms of temperature.

Both cities are in the Northern Hemisphere, so they share the same seasonal pattern in September.

Rainfall Comparison in September

Santo Domingo receives approximately 127 mm of rainfall across 21 rain days during September. Rain is frequent, so waterproof gear is essential.

San Juan sees 128 mm over 21 rain days. Both cities are equally rainy this month.

Both cities share similar humidity levels at 78%.

What to Pack: Santo Domingo vs San Juan

Packing for Santo Domingo in September

Highs of 30°C, lows of 23°C, 21 rain days

  • lightweight breathable clothing
  • sunscreen SPF 50+
  • sunglasses
  • a wide-brimmed hat
  • waterproof jacket
  • compact umbrella
  • waterproof shoes
  • moisture-wicking fabrics

Packing for San Juan in September

Highs of 31°C, lows of 25°C, 21 rain days

  • lightweight breathable clothing
  • sunscreen SPF 50+
  • sunglasses
  • a wide-brimmed hat
  • waterproof jacket
  • compact umbrella
  • waterproof shoes
  • moisture-wicking fabrics

Pack for both: lightweight breathable clothing, sunscreen SPF 50+, sunglasses, a wide-brimmed hat, waterproof jacket, compact umbrella, waterproof shoes, moisture-wicking fabrics. These items are useful in either destination during September.

Year-Round Comparison: Santo Domingo vs San Juan

The table below shows average high temperatures and rain days for every month of the year, helping you find the best time to visit either city.September is highlighted for quick reference.

MonthSanto DomingoSan Juan
HighRainHighRain
Jan27°C12d28°C11d
Feb28°C11d29°C9d
Mar28°C12d29°C9d
Apr29°C16d30°C12d
May29°C21d30°C17d
Jun30°C22d31°C14d
Jul30°C22d31°C17d
Aug30°C22d31°C19d
Sep30°C21d31°C21d
Oct29°C22d30°C21d
Nov28°C16d29°C19d
Dec28°C12d28°C13d
30°

Santo Domingo Weather in September

Full forecast, packing tips, and activities

31°

San Juan Weather in September

Full forecast, packing tips, and activities

Frequently Asked Questions

Is Santo Domingo warmer than San Juan in September?
No. In September, San Juan is warmer with an average high of 31°C (88°F) compared to Santo Domingo at 30°C (86°F), a difference of 1°C.
Which city gets more rain in September, Santo Domingo or San Juan?
Both cities average 21 rain days in September with similar precipitation levels.
Is it better to visit Santo Domingo or San Juan in September?
It depends on your preferences. Santo Domingo averages 30°C and 10 hours of daily sunshine with 21 rain days. San Juan averages 31°C with 11 sunshine hours and 21 rain days. If you prefer cooler conditions, choose San Juan. For fewer rain days, both are equal.
How far apart are Santo Domingo and San Juan?
Santo Domingo and San Juan are approximately 403 km (250 miles) apart. Santo Domingo is located in Dominican Republic (North America) while San Juan is in Puerto Rico (North America).
What is the best month to visit Santo Domingo and San Juan?
For Santo Domingo, April tends to be the best month with 12 hours of daily sunshine and a high of 29°C. For San Juan, April is typically ideal with 12 sunshine hours and 30°C highs.

Compare Santo Domingo and San Juan in Other Months

Climate data sourced from the Open-Meteo Historical Weather API, using ERA5 reanalysis data covering 30-year normals from 1991 to 2020. All temperatures shown in Celsius with Fahrenheit equivalents. Rain days count days with 1 mm or more of precipitation. Sunshine hours represent average daily values. This comparison is generated from long-term climate averages and individual trips may vary.

Santo Domingo coordinates: 18.49°N, -69.93°E | San Juan coordinates: 18.47°N, -66.11°E