Oiapoque weather in September

In September, Oiapoque sees average daytime highs of 33°C and overnight lows near 23°C, with 36 mm of rain across 7.1 wet days and about 12 hours of daylight. It is the 2nd-warmest and 12th-wettest month of the year here.

Day-to-day highs hold fairly steady near 33°C through the month. The sky is clear or mostly clear about 61% of the time in September, and the air most often feels oppressive.

Daylight stretches from about 12 h 06 min at the start of September to 12 hours by month's end. Set against the rest of the year, September is Oiapoque's 1st-clearest and 3rd-windiest month. For the whole year in context, see Oiapoque's year-round climate.

Daytime high
33°
2nd warmest
Overnight low
23°
3rd coldest
Rainfall
36 mm
7.1 wet days
Daylight
12 hours
6:21 AM – 6:22 PM
Cloud cover
39%
1st clearest
Wind
8 km/h
3rd windiest
Solar energy
6 kWh/m²
Travel score
4.1
out of 10

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 33°C through the month.

A typical September day in Oiapoque reaches about 33°C in the afternoon and slips back to 23°C overnight — a 10°C spread between the day's warmth and the night's chill. On most days the high lands between 31°C and 34°C. Set against its neighbours, September runs about 1°C warmer than August and on par with October.

20°25°30°35°151015202530
Avg high (°C)Avg low (°C)
13223
23223
33223
43223
53223
63223
73223
83223
93223
103223
113223
123323
133323
143323
153323
163323
173323
183323
193323
203323
213323
223323
233323
243323
253323
263323
273323
283323
293323
303323

How September really feels in Oiapoque

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.

Oiapoque weather by month

How September compares with the rest of the year at a glance. September is the 2nd-warmest and 12th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan29° / 23°28426.911.83.4
Feb29° / 23°26222.811.93.5
Mar29° / 23°21323.6123.5
Apr29° / 23°27125.112.13.2
May29° / 23°38129.112.22.9
Jun30° / 23°27627.312.23.0
Jul30° / 23°19025.112.23.4
Aug31° / 23°9415.612.14.0
Sep33° / 23°367.1124.1
Oct33° / 23°418.211.93.7
Nov32° / 23°10616.411.83.4
Dec30° / 23°2342611.83.2

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 61% of the time in September, the clearest month of the year.

Beyond those clear spells, partly cloudy skies cover about 21% of September, with mostly cloudy or overcast conditions the remaining 18%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
18416
28416
38317
48317
58317
68218
78218
88218
98119
108119
118020
128119
138119
148119
158119
168119
178218
188218
198218
208317
218317
228317
238317
248317
258317
268416
278317
288317
298218
308218

Chance of precipitation in September

Any precipitation

Oiapoque gets around 36 mm of rain over 7.1 wet days in September, the driest month. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 25% and peaks near 29% on the wettest days.

0%10%20%30%40%151015202530
Rain chance (%)
129
228
327
426
526
626
726
826
926
1026
1126
1226
1326
1426
1525
1625
1725
1824
1924
2023
2123
2222
2322
2422
2522
2622
2722
2823
2923
3023

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 94% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

0%25%50%75%100%151015202530
Muggy (%)Oppressive (%)Miserable (%)
11963
21963
31972
42962
52962
62962
72962
83952
93952
103952
113952
123952
134942
144942
154942
164942
174942
184942
194942
205941
215941
225941
235941
246931
256931
266931
276931
287921
297921
307921

Wind in September

Winds average 8 km/h in September.

Across September, daily wind ranges from about 8 km/h on the calmest days to 8 km/h at its breeziest. It stays fairly steady from day to day.

051015151015202530
Wind speed (km/h)Feels
18calm
28calm
38calm
48calm
58calm
68calm
78calm
88calm
98calm
108calm
118calm
128calm
138calm
148calm
158calm
168calm
178calm
188calm
198calm
208calm
218calm
228calm
238calm
248calm
258calm
268calm
278calm
288calm
298calm
308calm

Sunrise & sunset in September

DaylightNight

Daylight runs from about 12 h 06 min at the start of September to 12 hours by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 6 minutes over September. Sunrise moves from 6:25 AM to 6:18 AM, and sunset from 6:29 PM to 6:16 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.16:256:29
212.16:256:29
312.16:246:28
412.16:246:28
512.16:246:27
612.16:246:27
712.16:236:27
812.06:236:26
912.06:236:26
1012.06:236:25
1112.06:226:25
1212.06:226:24
1312.06:226:24
1412.06:226:23
1512.06:216:23
1612.06:216:22
1712.06:216:22
1812.06:216:21
1912.06:206:21
2012.06:206:20
2112.06:206:20
2212.06:196:19
2312.06:196:19
2412.06:196:18
2512.06:196:18
2612.06:186:18
2712.06:186:17
2812.06:186:17
2912.06:186:16
3012.06:186:16

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 6 kWh/m² — the sunniest month for solar.

For context, solar energy here swings from a low near 3.68 kWh/m² to a high of 6 kWh/m² in September across the year — September's 6 kWh/m² sits near the top of that range.

0246151015202530
Solar energy (kWh/m²)Level
15.8Bright
25.9Bright
35.9Bright
45.9Bright
55.9Bright
65.9Bright
75.9Bright
85.9Bright
95.9Bright
105.9Bright
116.0Bright
126.0Bright
136.0Bright
146.0Bright
156.0Bright
166.0Bright
176.0Intense
186.0Intense
196.0Intense
206.0Intense
216.0Intense
226.0Intense
236.1Intense
246.1Intense
256.1Intense
266.1Intense
276.1Intense
286.1Intense
296.1Intense
306.1Intense
Planning a trip in September

Is September a good time to visit Oiapoque?

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

4.1
Sightseeing
1st-best month of the year
6.9
Beach & pool
1st-best month of the year

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

What to pack for Oiapoque in September

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

In September, Oiapoque sees daytime highs around 33°C and nights near 23°C. Pack light clothes and sun protection. About 7 days see rain.

light clothessun protection

Sea temperature near Oiapoque 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 64 km away) is warmest in October at about 29°C and coldest in February 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
Mar27Warm
Apr28Warm
May28Warm
Jun28Tropical
Jul29Tropical
Aug29Tropical
Sep29Tropical
Oct29Tropical
Nov29Tropical
Dec28Warm

UV index in Oiapoque 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 Oiapoque peaks around April 12 at about 14 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near November 23 at about 11 (extreme).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeApr 12UV 14Nov 23UV 11
UV index (midday)Level
Jan13Extreme
Feb14Extreme
Mar14Extreme
Apr14Extreme
May13Extreme
Jun12Extreme
Jul11Extreme
Aug11Extreme
Sep12Extreme
Oct13Extreme
Nov11Extreme
Dec11Extreme

Air quality in Oiapoque 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 Oiapoque is worst in February — around 26 µg/m³ PM2.5 (moderate), about 3.9× the cleanest month (August, 7 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecModerateGoodModerateFeb 1925 µg/m³Aug 117 µg/m³
PM2.5 (µg/m³)Level
Jan22Moderate
Feb26Moderate
Mar25Moderate
Apr23Moderate
May15Moderate
Jun9Good
Jul7Good
Aug7Good
Sep8Good
Oct10Good
Nov11Good
Dec18Moderate
Location & terrain

Where is Oiapoque?

Oiapoque sits at 3.8°N, 51.8°W, 18 m above sea level, in Brazil. The nearest listed city is Matoury, 124 km away.

Saint-Laurent-du-MaroniPorto GrandeBlauwgrondRainville

Topography around Oiapoque

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

Within 3 km, the terrain around Oiapoque has only modest variations in elevation — a maximum elevation change of 97 m around an average of 28 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 124 m; within 80 km, significant variations in elevation — a maximum elevation change of 482 m.

The land around Oiapoque is covered by trees (72%) within 3 km, trees (93%) within 16 km, and trees (75%) within 80 km.

3 km
97 m
16 km
124 m
80 km
482 m
treesgrasslandartificial surfaceswaterwetlandmangroves
September weather nearby: Matoury 124 km · Rémire-Montjoly 129 km · Cayenne 134 km · Kourou 172 km · Saint-Laurent-du-Maroni 305 km · Porto Grande 351 km · Blauwgrond 426 km · Rainville 428 km

Brazil travel facts

Travel advisory
Level 2
Exercise Increased Caution
Power plugs
Type C / N
127 / 220 V · 60 Hz
Prices
≈ 46% of US
price level, 2025
GDP per capita
$10,713
2025
Happiness
6.6 / 10
World Happiness, 2025
Safe drinking water
89%
of population, 2024
Homicide rate
19.3
per 100k, 2023
Road deaths
16
per 100k/yr, 2019
Income group
Upper middle
World Bank
English
Low
EF EPI 482
Religion
Roman Catholic 57%Evangelical 27%none 9%other 4%

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 Oiapoque (3.8431°, -51.835°, elevation 18 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).