ClimateExplore the planning map
Climate · Arenal

Arenal in September

Warm and wet, as the days shorten.

Typical weather, averaged over 30 years

September in Arenal is warm: highs near 84°F, lows near 70°F. Rain falls on almost every day, and the days shorten by 13 minutes from the first week to the last.September in Arenal is warm: highs near 29°C, lows near 21°C. Rain falls on almost every day, and the days shorten by 13 minutes from the first week to the last.

High
84°F29°Caverage
Low
70°F21°Caverage
Wet days
7a week · 97% of days
Daylight
12h 10mon average

Is September a good time to visit Arenal?

A good month, just outside Arenal's best months, which run from January to March.

How we judge it: every month is scored on how close its typical high comes to the range from 70°F to 80°F, how mild its nights are, and how rarely it rains. The best months are the run of months that scores best.How we judge it: every month is scored on how close its typical high comes to the range from 21°C to 27°C, how mild its nights are, and how rarely it rains. The best months are the run of months that scores best.

How September sits in the year

week by week

Temperature

Highs near 84°F in September, against 81°F to 87°F through the year.Highs near 29°C in September, against 27°C to 31°C through the year.

Chance of a wet day

97% of days in September, against 28% to 99% through the year.

Cloud cover

79% cover in September, against 51% to 83% through the year.

Daylight

12h 10m in September, against 11h 31m to 12h 44m through the year.

Week by week, lightly smoothed, with September shaded. The olive line marks the best months. Hover or tap a week for its figures.

Either side

  1. August84°29°low 70°low 21°7 wet days a weekRain on almost every day.
  2. September84°29°low 70°low 21°7 wet days a weekRain on almost every day.
  3. October83°28°low 70°low 21°7 wet days a weekRain on almost every day.

Where Arenal sits, in September

America/Costa Rica
this place
typical high in September 40°F4°C95°F35°C
Sunrise, mid-September
5:28 AMsets 5:40 PM
Above the sea
410 mlow-lying
Latitude
10.5°Nnorthern hemisphere
Nearest of ours
Bijagua51 km north-west

The land around Arenal, shaded by its typical high in September, the planning map's own layer. Hover the map for the figure at that spot; tap it on a phone. Clock times are local, for the 15th.

Elsewhere in Costa Rica in September

high · low · wet days
See September on the planning mapThe whole year in Arenal

Typical weather, averaged over 30 years (1995–2024), from the 11 km grid square nearest Arenal. Temperatures are adjusted against 66 weather stations: daytime highs read about 3.1°F cold in the source data and are raised to match, and both highs and lows are adjusted for the town's height (410 m) against the climate model's (533 m).Temperatures are adjusted against 66 weather stations: daytime highs read about 1.7°C cold in the source data and are raised to match, and both highs and lows are adjusted for the town's height (410 m) against the climate model's (533 m). Daylight is calculated from latitude. Charts are lightly smoothed week to week; the figures in the table are not. Source: Copernicus ERA5-Land reanalysis; cloud cover from NASA's MERRA-2 reanalysis, on a coarser grid of about 50 km. Contains modified Copernicus Climate Change Service information 2026; neither the European Commission nor ECMWF is responsible for any use of it. These are averages, not a forecast.

Daylight is calculated from latitude. Charts are lightly smoothed week to week; the figures in the table are not.

Source: Copernicus ERA5-Land reanalysis; cloud cover from NASA's MERRA-2 reanalysis, on a coarser grid of about 50 km. Contains modified Copernicus Climate Change Service information 2026; neither the European Commission nor ECMWF is responsible for any use of it. These are averages, not a forecast.