Arenillas weather in September

In September, Arenillas sees average daytime highs of 26°C and overnight lows near 20°C, with 33 mm of rain across 8.2 wet days and about 12 hours of daylight. It is the 10th-warmest and 11th-wettest month of the year here.

Day-to-day highs hold fairly steady near 26°C through the month. The sky is clear or mostly clear about 1% of the time in September, and the air most often feels muggy.

Daylight stretches from about 11 h 54 min at the start of September to 12 hours by month's end. Set against the rest of the year, September is Arenillas's 3rd-clearest and 3rd-windiest month. For the whole year in context, see Arenillas's year-round climate.

Daytime high
26°
10th warmest
Overnight low
20°
2nd coldest
Rainfall
33 mm
8.2 wet days
Daylight
12 hours
6:15 AM – 6:14 PM
Cloud cover
80%
3rd clearest
Wind
6 km/h
3rd windiest
Solar energy
5.51 kWh/m²
Travel score
6.4
out of 10

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 26°C through the month.

A typical September day in Arenillas reaches about 26°C in the afternoon and slips back to 20°C overnight — a 7°C spread between the day's warmth and the night's chill. On most days the high lands between 24°C and 28°C. Set against its neighbours, September runs on par with August and on par with October.

15°20°25°30°151015202530
Avg high (°C)Avg low (°C)
12619
22619
32619
42619
52619
62619
72619
82619
92620
102620
112620
122620
132620
142620
152620
162620
172620
182720
192720
202720
212720
222720
232720
242720
252720
262720
272720
282720
292720
302720

How September really feels in Arenillas

Once humidity and wind are folded in, September averages 0 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
0
heat index over the day's high
Days feeling ≤ C
0
wind chill below the day's low

September sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.

Arenillas weather by month

How September compares with the rest of the year at a glance. September is the 10th-warmest and 11th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan28° / 22°24626.512.23.4
Feb29° / 23°36626.312.13.0
Mar29° / 23°46127.9123.1
Apr29° / 23°29825.511.93.3
May28° / 22°19224.711.83.8
Jun27° / 21°8118.511.84.9
Jul26° / 20°5215.611.85.5
Aug26° / 19°309.311.96.4
Sep26° / 20°338.2126.4
Oct27° / 20°4712.312.15.7
Nov27° / 20°6213.312.25.4
Dec28° / 21°12920.412.24.4

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 12% of September, with mostly cloudy or overcast conditions the remaining 87%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
11585
21585
31684
41684
51783
61783
71783
81783
91783
101684
111684
121684
131585
141585
151486
161288
171288
181189
191090
201090
211090
221090
23991
24991
25991
26991
27991
28991
29991
30991

Chance of precipitation in September

Any precipitation

Arenillas gets around 33 mm of rain over 8.2 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 28% and peaks near 34% on the wettest days. The odds climb toward the end of the month.

0%10%20%30%40%151015202530
Rain chance (%)
123
223
323
423
524
624
724
825
925
1025
1126
1226
1326
1427
1527
1628
1728
1829
1929
2029
2130
2230
2330
2431
2531
2632
2732
2833
2933
3034

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, September lands in the muggy band about 94% of days. Sticky, muggy-or-worse air turns up on roughly 99% of them.

0%25%50%75%100%151015202530
Humid (%)Muggy (%)Oppressive (%)
12953
22953
32953
41963
51963
61963
71963
81963
91963
101954
111954
121954
131954
141954
151954
161954
171945
181945
191945
201945
211945
221945
231945
241936
251936
261936
271936
281936
291936
300946

Wind in September

Winds average 6 km/h in September.

Across September, daily wind ranges from about 6 km/h on the calmest days to 6 km/h at its breeziest. It stays fairly steady from day to day.

0246810151015202530
Wind speed (km/h)Feels
16calm
26calm
36calm
46calm
56calm
66calm
76calm
86calm
96calm
106calm
116calm
126calm
136calm
146calm
156calm
166calm
176calm
186calm
196calm
206calm
216calm
226calm
236calm
246calm
256calm
266calm
276calm
286calm
296calm
306calm

Sunrise & sunset in September

DaylightNight

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

Days grow by about 6 minutes over September. Sunrise moves from 6:22 AM to 6:09 AM, and sunset from 6:18 PM to 6:10 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
111.96:226:18
211.96:226:18
311.96:216:17
411.96:216:17
511.96:206:17
611.96:206:17
712.06:196:16
812.06:196:16
912.06:186:16
1012.06:186:16
1112.06:186:15
1212.06:176:15
1312.06:176:15
1412.06:166:15
1512.06:166:14
1612.06:156:14
1712.06:156:14
1812.06:146:13
1912.06:146:13
2012.06:136:13
2112.06:136:13
2212.06:126:12
2312.06:126:12
2412.06:116:12
2512.06:116:12
2612.06:116:11
2712.06:106:11
2812.06:106:11
2912.06:096:11
3012.06:096:10

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 5.51 kWh/m² — the sunniest month for solar.

For context, solar energy here swings from a low near 4.58 kWh/m² to a high of 5.51 kWh/m² in September across the year — September's 5.51 kWh/m² sits near the top of that range.

0246151015202530
Solar energy (kWh/m²)Level
15.5Bright
25.5Bright
35.5Bright
45.6Bright
55.6Bright
65.6Bright
75.5Bright
85.5Bright
95.5Bright
105.5Bright
115.5Bright
125.5Bright
135.5Bright
145.5Bright
155.5Bright
165.5Bright
175.5Bright
185.5Bright
195.5Bright
205.5Bright
215.5Bright
225.5Bright
235.4Bright
245.4Bright
255.4Bright
265.4Bright
275.4Bright
285.4Bright
295.4Bright
305.4Bright
Planning a trip in September

Hazard calendar for Arenillas

In seasonPeak

None of Arenillas's seasonal hazards are active in September. The full-year calendar below shows when the rainy season, cyclone risk and dust haze do peak.

Arenillas's monsoon runs January–April, 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 Arenillas?

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

6.4
Sightseeing
1st-best month of the year
6.3
Beach & pool
1st-best month of the year

September is a reasonable time to visit Arenillas for sightseeing. The water and warmth also suit a beach or pool day.

What to pack for Arenillas in September

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

In September, Arenillas sees daytime highs around 26°C and nights near 20°C. Worth packing: light clothes, rain gear and sun protection. About 8 days see rain.

light clothesrain gearsun protection

Sea temperature near Arenillas in September

The nearest coast averages about 23°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 40 km away) is warmest in March at about 27°C and coldest in September near 23°C.

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

22°24°26°28°JanFebMarAprMayJunJulAugSepOctNovDecrefreshingwarmcomfortable to swim
Sea temperature (°C)Comfort
Jan26Warm
Feb26Warm
Mar27Warm
Apr26Warm
May26Warm
Jun25Warm
Jul24Refreshing
Aug23Refreshing
Sep23Refreshing
Oct23Refreshing
Nov24Refreshing
Dec25Warm

UV index in Arenillas 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 Arenillas peaks around February 21 at about 15 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near July 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.

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeExtremeFeb 21UV 15Jul 16UV 10
UV index (midday)Level
Jan14Extreme
Feb15Extreme
Mar15Extreme
Apr12Extreme
May12Extreme
Jun10Extreme
Jul10Very high
Aug10Extreme
Sep12Extreme
Oct13Extreme
Nov12Extreme
Dec12Extreme

Air quality in Arenillas 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 Arenillas is worst in December — around 29 µg/m³ PM2.5 (moderate), about 3.1× the cleanest month (August, 9 µg/m³).

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

010203040JanFebMarAprMayJunJulAugSepOctNovDecModerateGoodModerateDec 1128 µg/m³Aug 219 µg/m³
PM2.5 (µg/m³)Level
Jan15Moderate
Feb14Moderate
Mar14Moderate
Apr15Moderate
May15Moderate
Jun15Moderate
Jul12Moderate
Aug9Good
Sep10Good
Oct14Moderate
Nov27Moderate
Dec29Moderate
Location & terrain

Where is Arenillas?

Arenillas sits at 3.6°S, 80.1°W, 41 m above sea level, in Ecuador. The nearest listed city is Santa Rosa, 16 km away.

Topography around Arenillas

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

Within 3 km, the terrain around Arenillas has only modest variations in elevation — a maximum elevation change of 134 m around an average of 48 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 507 m; within 80 km, extreme variations in elevation — a maximum elevation change of 3,874 m.

The land around Arenillas is covered by trees (41%) and grassland (39%) within 3 km, trees (45%) and grassland (34%) within 16 km, and trees (40%), water (28%) and grassland (23%) within 80 km.

3 km
134 m
16 km
507 m
80 km
3,874 m
treesshrubsgrasslandcroplandartificial surfacesbare terrainwatermangroves
September weather nearby: Santa Rosa 16 km · Huaquillas 20 km · Zarumilla 24 km · Machala 35 km · Pasaje 38 km · Tumbes 42 km · Guabo 43 km · Piñas 45 km

Ecuador travel facts

Travel advisory
Level 2
Exercise Increased Caution
Power plugs
Type A / B
120 V · 60 Hz
Prices
≈ 43% of US
price level, 2025
GDP per capita
$7,125
2025
Happiness
6.1 / 10
World Happiness, 2025
Safe drinking water
70%
of population, 2024
Homicide rate
45.7
per 100k, 2023
Road deaths
20.1
per 100k/yr, 2019
Income group
Upper middle
World Bank
English
Low
EF EPI 466
Religion
Roman Catholic 68%Protestant 19%none 8%other 2%

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 Arenillas (-3.554°, -80.0668°, elevation 41 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).