El Castillo weather in September

In September, El Castillo sees average daytime highs of 31°C and overnight lows near 23°C, with 290 mm of rain across 29.4 wet days and about 12.1 hours of daylight. It is the 3rd-warmest and 3rd-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 2% 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 El Castillo's 8th-clearest and 12th-windiest month. For the whole year in context, see El Castillo's year-round climate.

Daytime high
31°
3rd warmest
Overnight low
23°
8th coldest
Rainfall
290 mm
29.4 wet days
Daylight
12 h 06 min
5:30 AM – 5:34 PM
Cloud cover
86%
8th clearest
Wind
5 km/h
12th windiest
Solar energy
4.19 kWh/m²
Travel score
2.4
out of 10

El Castillo is historic village in Río San Juan Department, Nicaragua.

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

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 El Castillo reaches about 31°C in the afternoon and slips back to 23°C overnight — a 7°C spread between the day's warmth and the night's chill. On most days the high lands between 28°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 El Castillo

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.

El Castillo weather by month

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

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan28° / 22°6020.211.45.0
Feb29° / 22°4115.911.64.9
Mar30° / 22°311211.94.9
Apr31° / 23°4713.412.23.9
May31° / 24°22025.912.52.7
Jun30° / 24°29729.612.62.5
Jul30° / 23°27130.312.62.7
Aug30° / 23°26029.912.42.6
Sep31° / 23°29029.412.12.4
Oct30° / 23°30129.711.82.7
Nov29° / 23°2122611.53.3
Dec28° / 22°11224.211.44.0

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 2% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 7% of September, with mostly cloudy or overcast conditions the remaining 90%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
1991
2991
31090
41090
51090
61090
71090
81090
91090
101090
111189
121189
131189
141189
151189
161189
171189
181189
191090
201090
21991
22991
23991
24991
25991
26991
27991
28793
29793
30793

Chance of precipitation in September

Any precipitation

El Castillo gets around 290 mm of rain over 29.4 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 98% and peaks near 99% on the wettest days.

0%20%40%60%80%100%151015202530
Rain chance (%)
196
296
396
496
596
696
797
897
997
1097
1198
1298
1398
1498
1599
1699
1799
1899
1999
2099
2199
2299
2399
2499
2599
2699
2798
2898
2998
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 54% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

0%25%50%75%100%151015202530
Oppressive (%)Miserable (%)
16040
25941
35941
45842
55842
65743
75743
85644
95644
105545
115446
125347
135347
145248
155149
165149
175149
185149
195149
205149
215149
225149
235248
245248
255248
265347
275347
285446
295446
305545

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 5:31 AM to 5:29 AM, and sunset from 5:44 PM to 5:24 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.25:315:44
212.25:315:43
312.25:315:42
412.25:315:42
512.25:315:41
612.25:315:40
712.25:315:40
812.15:315:39
912.15:315:38
1012.15:305:38
1112.15:305:37
1212.15:305:36
1312.15:305:36
1412.15:305:35
1512.15:305:34
1612.15:305:34
1712.05:305:33
1812.05:305:32
1912.05:305:32
2012.05:305:31
2112.05:305:30
2212.05:305:30
2312.05:305:29
2412.05:305:28
2512.05:305:28
2612.05:305:27
2711.95:305:26
2811.95:305:26
2911.95:305:25
3011.95:295:24

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.19 kWh/m².

For context, solar energy here swings from a low near 3.27 kWh/m² to a high of 5.42 kWh/m² in April across the year — September's 4.19 kWh/m² falls in the middle.

012345151015202530
Solar energy (kWh/m²)Level
14.2Bright
24.2Bright
34.2Bright
44.2Bright
54.2Bright
64.2Bright
74.2Bright
84.2Bright
94.2Bright
104.2Bright
114.2Bright
124.2Bright
134.2Bright
144.2Bright
154.2Bright
164.2Bright
174.2Bright
184.2Bright
194.2Bright
204.2Bright
214.2Bright
224.2Bright
234.2Bright
244.1Bright
254.1Bright
264.1Bright
274.1Bright
284.1Bright
294.1Bright
304.1Bright
Planning a trip in September

Hazard calendar for El Castillo

In seasonPeak

In September, El Castillo sits inside its atlantic hurricane and rainy season season. The full year is below, with each hazard's peak months called out.

El Castillo sits in the Atlantic hurricane belt; the season peaks August–October.

El Castillo's rainy season runs May–November, when most of the year's rain falls.

Atlantic hurricane
Rainy season
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Is September a good time to visit El Castillo?

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

2.4
Sightseeing
12th-best month of the year
3.5
Beach & pool
11th-best month of the year

September is a weaker month for outdoor sightseeing in El Castillo.

What to pack for El Castillo in September

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

In September, El Castillo sees daytime highs around 31°C and nights near 23°C. Pack light clothes and rain gear. About 29 days see rain.

light clothesrain gear

Sea temperature near El Castillo 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 69 km away) is warmest in September at about 29°C and coldest in January near 27°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
Jan27Warm
Feb27Warm
Mar28Warm
Apr28Tropical
May29Tropical
Jun29Tropical
Jul28Tropical
Aug29Tropical
Sep29Tropical
Oct29Tropical
Nov28Tropical
Dec27Warm

UV index in El Castillo 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 El Castillo peaks around March 19 at about 14 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 16 at about 9 (very high).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeVery highMar 19UV 14Dec 16UV 9
UV index (midday)Level
Jan11Extreme
Feb13Extreme
Mar14Extreme
Apr13Extreme
May12Extreme
Jun13Extreme
Jul12Extreme
Aug13Extreme
Sep12Extreme
Oct12Extreme
Nov10Extreme
Dec9Very high

Air quality in El Castillo 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 El Castillo is worst in July — around 24 µg/m³ PM2.5 (moderate), about 3.6× the cleanest month (December, 7 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodJul 1623 µg/m³Dec 127 µg/m³
PM2.5 (µg/m³)Level
Jan7Good
Feb9Good
Mar10Good
Apr18Moderate
May22Moderate
Jun20Moderate
Jul24Moderate
Aug19Moderate
Sep13Moderate
Oct10Good
Nov7Good
Dec7Good
Location & terrain

Where is El Castillo?

El Castillo sits at 11.0°N, 84.4°W, 0 m above sea level, in Nicaragua. The nearest listed city is San Carlos, 43 km away.

San CarlosNueva GuineaSan José

Topography around El Castillo

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

Within 3 km, the terrain around El Castillo has only modest variations in elevation — a maximum elevation change of 128 m around an average of 59 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 403 m; within 80 km, very significant variations in elevation — a maximum elevation change of 2,141 m.

The land around El Castillo is covered by trees (69%) and grassland (26%) within 3 km, trees (67%) and grassland (31%) within 16 km, and trees (60%) and grassland (28%) within 80 km.

3 km
128 m
16 km
403 m
80 km
2,141 m
treesgrasslandcroplandwater
September weather nearby: San Carlos 43 km · La Fortuna 67 km · Nueva Guinea 75 km · Quesada 77 km · San José 81 km · Monteverde 91 km · Cañas 101 km · San_Ramon_ 104 km

Nicaragua travel facts

Travel advisory
Level 3
Reconsider Travel
Power plugs
Type A / B
120 V · 60 Hz
Prices
≈ 34% of US
price level, 2025
GDP per capita
$3,173
2025
Happiness
6.3 / 10
World Happiness, 2025
Homicide rate
11.3
per 100k, 2021
Road deaths
16.9
per 100k/yr, 2019
Income group
Lower middle
World Bank
English
Moderate
EF EPI 512
Religion
Roman Catholic 45%Protestant 39%none 14%other 1%

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 El Castillo (11.0189°, -84.397°, 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. Tropical-cyclone seasons are the published climatological basin seasons (NOAA National Hurricane Center / regional warning centres). 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).