La Fortuna weather in September

In September, La Fortuna sees average daytime highs of 28°C and overnight lows near 21°C, with 288 mm of rain across 29 wet days and about 12.1 hours of daylight. It is the 3rd-warmest and 4th-wettest month of the year here.

Day-to-day highs hold fairly steady near 28°C through the month. The sky is clear or mostly clear about 1% of the time in September, and the air most often feels oppressive.

Daylight stretches from about 12 h 12 min at the start of September to 11 h 54 min by month's end. Set against the rest of the year, September is La Fortuna's 8th-clearest and 12th-windiest month. For the whole year in context, see La Fortuna's year-round climate.

Daytime high
28°
3rd warmest
Overnight low
21°
9th coldest
Rainfall
288 mm
29 wet days
Daylight
12 h 06 min
5:31 AM – 5:35 PM
Cloud cover
88%
8th clearest
Wind
5 km/h
12th windiest
Solar energy
4.27 kWh/m²
Travel score
3.3
out of 10

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 28°C through the month.

A typical September day in La Fortuna reaches about 28°C in the afternoon and slips back to 21°C overnight — a 7°C spread between the day's warmth and the night's chill. On most days the high lands between 26°C and 29°C. Set against its neighbours, September runs on par with August and on par with October.

20°23°25°28°30°151015202530
Avg high (°C)Avg low (°C)
12821
22821
32821
42821
52821
62821
72821
82821
92821
102821
112821
122821
132821
142821
152821
162821
172821
182821
192821
202821
212821
222821
232821
242821
252821
262821
272821
282821
292821
302821

La Fortuna weather by month

How September compares with the rest of the year at a glance. September is the 3rd-warmest and 4th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan26° / 19°11015.311.56.1
Feb26° / 19°548.111.77.1
Mar28° / 20°326.611.97.0
Apr29° / 21°521012.25.5
May28° / 21°25524.612.53.7
Jun28° / 21°30428.812.63.3
Jul27° / 21°26028.112.63.6
Aug28° / 21°24328.512.33.5
Sep28° / 21°2882912.13.3
Oct27° / 21°31929.711.83.4
Nov26° / 20°2912611.53.9
Dec26° / 20°19721.911.44.9

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 1% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 6% of September, with mostly cloudy or overcast conditions the remaining 94%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
1595
2595
3595
4595
5694
6694
7694
8694
9694
10793
11793
12793
13793
14793
15892
16892
17793
18793
19793
20793
21793
22793
23694
24694
25694
26595
27595
28595
29496
30496

Chance of precipitation in September

Any precipitation

La Fortuna gets around 288 mm of rain over 29 wet days in September. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 96% and peaks near 97% on the wettest days.

0%20%40%60%80%100%151015202530
Rain chance (%)
195
295
396
496
596
696
796
896
996
1096
1196
1296
1396
1496
1596
1696
1797
1897
1997
2097
2197
2297
2397
2497
2597
2697
2797
2897
2997
3097

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

Most of September feels oppressive — the stacked bands show each day's mix of comfort levels, read off the dew point.

By dew point, September lands in the oppressive band about 96% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

0%25%50%75%100%151015202530
Muggy (%)Oppressive (%)
1397
2397
3397
4397
5397
6397
7397
8397
9397
10496
11496
12496
13496
14496
15496
16496
17496
18496
19496
20496
21496
22496
23496
24496
25496
26595
27595
28595
29595
30694

Wind in September

Winds average 5 km/h in September, the calmest month.

Across September, daily wind ranges from about 4 km/h on the calmest days to 5 km/h at its breeziest. It stays fairly steady from day to day.

0246810151015202530
Wind speed (km/h)Feels
15calm
25calm
35calm
45calm
55calm
65calm
75calm
85calm
95calm
105calm
115calm
125calm
135calm
145calm
155calm
164calm
174calm
184calm
194calm
204calm
214calm
224calm
234calm
244calm
255calm
265calm
275calm
285calm
295calm
305calm

Sunrise & sunset in September

DaylightNight

Daylight runs from about 12 h 12 min at the start of September to 11 h 54 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 18 minutes over September. Sunrise moves from 5:32 AM to 5:30 AM, and sunset from 5:44 PM to 5:25 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.25:325:44
212.25:325:44
312.25:325:43
412.25:325:43
512.25:325:42
612.25:325:41
712.15:325:41
812.15:325:40
912.15:325:39
1012.15:325:39
1112.15:325:38
1212.15:315:37
1312.15:315:37
1412.15:315:36
1512.15:315:35
1612.15:315:35
1712.05:315:34
1812.05:315:33
1912.05:315:33
2012.05:315:32
2112.05:315:31
2212.05:315:31
2312.05:315:30
2412.05:315:29
2512.05:315:29
2612.05:315:28
2711.95:305:27
2811.95:305:27
2911.95:305:26
3011.95:305:25

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.27 kWh/m².

For context, solar energy here swings from a low near 3.65 kWh/m² to a high of 5.86 kWh/m² in March across the year — September's 4.27 kWh/m² falls in the middle.

012345151015202530
Solar energy (kWh/m²)Level
14.4Bright
24.4Bright
34.4Bright
44.4Bright
54.4Bright
64.4Bright
74.4Bright
84.3Bright
94.3Bright
104.3Bright
114.3Bright
124.3Bright
134.3Bright
144.3Bright
154.3Bright
164.3Bright
174.3Bright
184.2Bright
194.2Bright
204.2Bright
214.2Bright
224.2Bright
234.2Bright
244.2Bright
254.2Bright
264.1Bright
274.1Bright
284.1Bright
294.1Bright
304.1Bright
Planning a trip in September

Is September a good time to visit La Fortuna?

Our two travel scores rate September for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).

3.3
Sightseeing
11th-best month of the year
3.6
Beach & pool
11th-best month of the year

September is a weaker month for outdoor sightseeing in La Fortuna.

What to pack for La Fortuna in September

From September's temperature range, rain chance, sun and wind — what's worth putting in the bag.

In September, La Fortuna sees daytime highs around 28°C and nights near 21°C. Pack light clothes and rain gear. About 29 days see rain.

light clothesrain gear

Sea temperature near La Fortuna in September

The nearest coast averages about 29°C in September — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea at the nearest coast (about 66 km away) is warmest in April at about 29°C and coldest in November near 28°C.

The water stays above 20°C all year — warm enough for a swim any month.

26°28°30°JanFebMarAprMayJunJulAugSepOctNovDecwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan29Tropical
Feb29Tropical
Mar29Tropical
Apr29Tropical
May29Tropical
Jun29Tropical
Jul29Tropical
Aug29Tropical
Sep29Tropical
Oct28Tropical
Nov28Warm
Dec28Tropical

UV index in La Fortuna in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 13 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in La Fortuna peaks around March 17 at about 14 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 16 at about 10 (very high).

The index reaches 3 or more — the level where the WHO recommends sun protection — every month of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeMar 17UV 14Dec 16UV 10
UV index (midday)Level
Jan11Extreme
Feb14Extreme
Mar14Extreme
Apr14Extreme
May13Extreme
Jun13Extreme
Jul12Extreme
Aug13Extreme
Sep13Extreme
Oct12Extreme
Nov11Extreme
Dec10Very high

Air quality in La Fortuna in September

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where September falls, not just the annual average.

Air quality in La Fortuna is worst in May — around 23 µg/m³ PM2.5 (moderate), about 2.5× the cleanest month (January, 10 µg/m³).

Modeled monthly averages (CAMS reanalysis, 2015–2024).

0102030JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodMay 1623 µg/m³Jan 1210 µg/m³
PM2.5 (µg/m³)Level
Jan10Good
Feb11Good
Mar13Moderate
Apr21Moderate
May23Moderate
Jun21Moderate
Jul22Moderate
Aug20Moderate
Sep18Moderate
Oct15Moderate
Nov12Good
Dec10Good
Location & terrain

Where is La Fortuna?

La Fortuna sits at 10.5°N, 84.6°W, 0 m above sea level, in Costa Rica. The nearest listed city is Monteverde, 26 km away.

MonteverdeQuesadaSan_Ramon_CañasEsparzaChacaritaPuntarenasEl Castillo

Topography around La Fortuna

How much the land rises and falls, and what covers it, within 3, 16 and 80 km of La Fortuna.

Within 3 km, the terrain around La Fortuna has significant variations in elevation — a maximum elevation change of 281 m around an average of 270 m above sea level; within 16 km, very significant variations in elevation — a maximum elevation change of 1,738 m; within 80 km, extreme variations in elevation — a maximum elevation change of 2,891 m.

The land around La Fortuna is covered by grassland (55%) and trees (42%) within 3 km, trees (63%) and grassland (35%) within 16 km, and trees (63%) and grassland (26%) within 80 km.

3 km
281 m
16 km
1,738 m
80 km
2,891 m
treesgrasslandcroplandartificial surfaceswatermangroves
September weather nearby: Monteverde 26 km · Quesada 28 km · San_Ramon_ 47 km · Cañas 50 km · Esparza 53 km · Chacarita 56 km · Puntarenas 59 km · El Castillo 67 km

Costa Rica travel facts

Travel advisory
Level 2
Exercise Increased Caution
Power plugs
Type A / B
120 V · 60 Hz
Prices
≈ 59% of US
price level, 2025
GDP per capita
$19,970
2025
Happiness
7.4 / 10
World Happiness, 2025
Safe drinking water
81%
of population, 2024
Homicide rate
17.7
per 100k, 2023
Road deaths
14.8
per 100k/yr, 2019
Income group
High
World Bank
English
Moderate
EF EPI 516
Religion
Roman Catholic 48%none 27%Evangelical and Pentecostal 20%other 3%

Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.

Data sources

Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for La Fortuna (10.4709°, -84.6453°, elevation 0 m), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google. Sea temperatures are the NOAA OISST v2.1 1991–2020 monthly climatology (public domain), sampled at the nearest ocean point. UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Monthly air-quality (PM2.5) seasonality is from the CAMS EAC4 reanalysis (Copernicus Atmosphere Monitoring Service), scaled to the WHO annual mean where available. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).