Nicoya weather in September

In September, Nicoya sees average daytime highs of 31°C and overnight lows near 23°C, with 347 mm of rain across 28.1 wet days and about 12.1 hours of daylight. It is the 10th-warmest and 2nd-wettest month of the year here.

Day-to-day highs hold fairly steady near 31°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 Nicoya's 11th-clearest and 12th-windiest month. For the whole year in context, see Nicoya's year-round climate.

Daytime high
31°
10th warmest
Overnight low
23°
6th coldest
Rainfall
347 mm
28.1 wet days
Daylight
12 h 06 min
5:34 AM – 5:38 PM
Cloud cover
87%
11th clearest
Wind
5 km/h
12th windiest
Solar energy
4.64 kWh/m²
Travel score
2.5
out of 10

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 31°C through the month.

A typical September day in Nicoya reaches about 31°C in the afternoon and slips back to 23°C overnight — a 8°C spread between the day's warmth and the night's chill. On most days the high lands between 29°C and 32°C. Set against its neighbours, September runs on par with August and on par with October.

20°25°30°35°151015202530
Avg high (°C)Avg low (°C)
13123
23123
33123
43123
53123
63123
73123
83123
93123
103123
113123
123123
133123
143123
153123
163123
173123
183123
193123
203023
213023
223023
233023
243023
253023
263023
273023
283023
293023
303023

How September really feels in Nicoya

Once humidity and wind are folded in, September averages 30 days that feel above 32°C and 0 that feel at or below 0°C — the comfort signal a plain temperature reading hides.

Days feeling ≥ 32°C
30
heat index over the day's high
Days feeling ≤ C
0
wind chill below the day's low

The story in September is heat — humidity pushes the afternoon "feels like" well above the raw temperature.

Nicoya weather by month

How September compares with the rest of the year at a glance. September is the 10th-warmest and 2nd-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan33° / 22°61.311.54.6
Feb34° / 23°71.911.73.9
Mar35° / 23°7211.93.1
Apr36° / 24°38712.22.2
May33° / 24°25120.512.52.4
Jun31° / 23°31926.212.62.6
Jul31° / 23°22622.412.53.0
Aug31° / 23°25724.412.32.8
Sep31° / 23°34728.112.12.5
Oct30° / 23°3592811.82.8
Nov30° / 22°14315.611.54.1
Dec31° / 22°213.611.45.1

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 5% of September, with mostly cloudy or overcast conditions the remaining 94%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
1793
2793
3793
4793
5793
6793
7793
8793
9793
10694
11694
12694
13694
14694
15694
16694
17694
18694
19694
20694
21694
22694
23694
24694
25694
26694
27694
28694
29694
30694

Chance of precipitation in September

Any precipitation

Nicoya gets around 347 mm of rain over 28.1 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 94% and peaks near 96% on the wettest days.

0%20%40%60%80%100%151015202530
Rain chance (%)
190
290
391
491
592
692
792
892
992
1092
1193
1293
1393
1493
1594
1694
1794
1895
1995
2095
2195
2295
2396
2496
2596
2696
2795
2895
2995
3095

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 80% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

0%25%50%75%100%151015202530
Muggy (%)Oppressive (%)Miserable (%)
118316
218217
318217
408218
508218
608218
708119
808119
908020
1008020
1107921
1207921
1307822
1407822
1507723
1607723
1707723
1807723
1907723
2007723
2107723
2207822
2307822
2407921
2507921
2608020
2708020
2808119
2908119
3008218

Wind in September

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

Across September, daily wind ranges from about 5 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
165calm
175calm
185calm
195calm
205calm
215calm
225calm
235calm
245calm
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 5:36 AM to 5:33 AM, and sunset from 5:47 PM to 5:29 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.25:365:47
212.25:365:47
312.25:355:46
412.25:355:46
512.25:355:45
612.25:355:44
712.15:355:44
812.15:355:43
912.15:355:42
1012.15:355:42
1112.15:355:41
1212.15:355:40
1312.15:355:40
1412.15:355:39
1512.15:355:38
1612.15:345:38
1712.05:345:37
1812.05:345:36
1912.05:345:36
2012.05:345:35
2112.05:345:34
2212.05:345:34
2312.05:345:33
2412.05:345:33
2512.05:345:32
2612.05:345:31
2711.95:345:31
2811.95:345:30
2911.95:345:29
3011.95:335:29

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.64 kWh/m².

For context, solar energy here swings from a low near 4.24 kWh/m² to a high of 6.79 kWh/m² in March across the year — September's 4.64 kWh/m² sits near the bottom.

024151015202530
Solar energy (kWh/m²)Level
14.9Bright
24.9Bright
34.8Bright
44.8Bright
54.8Bright
64.8Bright
74.8Bright
84.8Bright
94.8Bright
104.7Bright
114.7Bright
124.7Bright
134.7Bright
144.7Bright
154.6Bright
164.6Bright
174.6Bright
184.6Bright
194.6Bright
204.5Bright
214.5Bright
224.5Bright
234.5Bright
244.5Bright
254.5Bright
264.5Bright
274.4Bright
284.4Bright
294.4Bright
304.4Bright
Planning a trip in September

Hazard calendar for Nicoya

In seasonPeak

In September, Nicoya sits inside its monsoon season. The full year is below, with each hazard's peak months called out.

Nicoya's monsoon runs May–October, when most of the year's rain falls.

Monsoon
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Is September a good time to visit Nicoya?

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

2.5
Sightseeing
10th-best month of the year
3.7
Beach & pool
12th-best month of the year

September is a weaker month for outdoor sightseeing in Nicoya.

What to pack for Nicoya in September

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

In September, Nicoya sees daytime highs around 31°C and nights near 23°C. Pack light clothes and rain gear. Worth having: sun protection. About 28 days see rain.

light clothesrain gearsun protection

Sea temperature near Nicoya 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 32 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 Nicoya in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 12 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Nicoya peaks around March 16 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.

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeVery highMar 16UV 14Dec 16UV 10
UV index (midday)Level
Jan11Extreme
Feb13Extreme
Mar14Extreme
Apr13Extreme
May12Extreme
Jun13Extreme
Jul12Extreme
Aug12Extreme
Sep12Extreme
Oct11Extreme
Nov11Extreme
Dec9Very high

Air quality in Nicoya 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 Nicoya is worst in July — around 20 µg/m³ PM2.5 (moderate), about 3.2× the cleanest month (December, 6 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodJul 1619 µg/m³Dec 176 µg/m³
PM2.5 (µg/m³)Level
Jan7Good
Feb9Good
Mar11Good
Apr19Moderate
May19Moderate
Jun16Moderate
Jul20Moderate
Aug16Moderate
Sep12Good
Oct9Good
Nov7Good
Dec6Good
Location & terrain

Where is Nicoya?

Nicoya sits at 10.2°N, 85.5°W, 128 m above sea level, in Costa Rica. The nearest listed city is Tamarindo, 46 km away.

TamarindoCañasLiberiaPuntarenasMonteverdeChacaritaEsparzaLa Fortuna

Topography around Nicoya

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

Within 3 km, the terrain around Nicoya has significant variations in elevation — a maximum elevation change of 375 m around an average of 171 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 924 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,977 m.

The land around Nicoya is covered by trees (64%) and grassland (26%) within 3 km, trees (74%) and grassland (25%) within 16 km, and trees (41%) and water (41%) within 80 km.

3 km
375 m
16 km
924 m
80 km
1,977 m
treesgrasslandcroplandartificial surfaceswatermangroves
September weather nearby: Tamarindo 46 km · Cañas 50 km · Liberia 54 km · Puntarenas 70 km · Monteverde 72 km · Chacarita 76 km · Esparza 88 km · La Fortuna 95 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 Nicoya (10.1504°, -85.4509°, elevation 128 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).