The weather in September in Arenal

It's hot in September in Arenal with an average temperature of 32°C. Temperatures this month range from a low of 31°C to a high of 33°C. At night, you can expect temperatures between 23°C and 24°C.

Looking for sun? September isn’t a good month to be in Arenal. The temperature is nice, but there’s too much chance of rain.

Average temperatures and precipitation

This chart shows the average daily maximum and minimum temperatures (in degrees Celsius) and precipitation (in millimeters) in September for Arenal, Costa Rica. A low precipitation value usually indicates little to no rainfall on that day in recent years, while a higher value suggests more frequent rainfall.

Temperature records

With 36°C in 2023, Arenal reached the highest temperature in September over the past 10 years. The lowest daytime temperature in this month was 26°C in 2017. The extreme nighttime temperatures ranged from a lowest recorded value of 20°C to a highest value of 26°C.

Rainfall amount

In September, there is an average of 349 mm of precipitation, spread over 26 days. The wind speed is around 4 Bft, mostly coming from the South.

Daily weather in September for Arenal

Click on any day in September to get detailed info about the usual weather on that day in Arenal. Check out the historical temperatures and precipitation over the past 10 years on this day.

1

33° / 23°

2

33° / 23°

3

32° / 24°

4

33° / 23°

5

32° / 24°

6

32° / 23°

7

32° / 23°

8

32° / 23°

9

32° / 23°

10

32° / 23°

11

32° / 23°

12

31° / 23°

13

32° / 23°

14

32° / 24°

15

32° / 23°

16

33° / 23°

17

32° / 23°

18

33° / 24°

19

32° / 24°

20

31° / 24°

21

32° / 23°

22

32° / 23°

23

31° / 23°

24

31° / 23°

25

31° / 23°

26

32° / 23°

27

32° / 23°

28

32° / 23°

29

32° / 23°

30

32° / 23°

Start of September

The month of September starts in Arenal with hot temps, averaging around 33°C during the day and nights around 24°C.

Mid September

By mid-September, daytime temps drop to around 32°C, with nights around 24°C. There’s a high chance of precipitation during this time.

End of September

By the end of September, the average daytime temperature in Arenal is around 32°C, while nighttime temps are about 23°C. There’s a significant chance of many days with precipitation.

Find affordable trips to Arenal

UV index

The UV index is a maximum of 9 this month. That's a very high value on the intensity scale of 1 to 11. Unprotected skin can burn within 10-15 minutes.

The hurricane season in Arenal runs from June to November.

Check out the climate of Arenal for all months and discover the best travel time

Temperature charts

These charts show the average temperatures in September in Arenal, Costa Rica. The temperatures are shown in degrees Celsius and are calculated based on data from the past 10 years.

Daily Temperature in September in Arenal

Temperature in September in Arenal over the years

Precipitation charts

These charts show the average amount of precipitation in September in Arenal, Costa Rica. Precipitation is always measured as water, even when it falls as snow or hail The amount of precipitation is displayed in millimeters, while snowfall is shown in centimeters.

Daily Precipitation in September in Arenal

Total precipitation in September in Arenal over the years

Daily UV index in September in Arenal

This chart shows the average daily UV index in September in Arenal, with the UV index ranging from 0 to a maximum of 11. The bottom of the chart shows the days of the month. Based on historical data, this chart provides an idea of the daily UV radiation levels you can expect.

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Average weather in Arenal by month

Click on a month below to see detailed weather info for Arenal. Based on historical weather data, you can see the average temperature, precipitation, wind, and UV index for each day of the month.