Barreirinhas weather in September

In September, Barreirinhas sees average daytime highs of 32°C and overnight lows near 25°C, with 3 mm of rain across 0.8 wet days and about 12 hours of daylight. It is the 1st-warmest and 12th-wettest month of the year here.

Day-to-day highs hold fairly steady near 32°C through the month. The sky is clear or mostly clear about 83% of the time in September, and the air most often feels oppressive.

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 Barreirinhas's 1st-clearest and 2nd-windiest month. For the whole year in context, see Barreirinhas's year-round climate.

Daytime high
32°
1st warmest
Overnight low
25°
9th coldest
Rainfall
3 mm
0.8 wet days
Daylight
12 hours
5:46 AM – 5:45 PM
Cloud cover
28%
1st clearest
Wind
19 km/h
2nd windiest
Solar energy
6.73 kWh/m²
Travel score
5.1
out of 10

Barreirinhas is principal settlement in Barreirinhas Municipality, Maranhão, Brazil.

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 32°C through the month.

A typical September day in Barreirinhas reaches about 32°C in the afternoon and slips back to 25°C overnight — a 7°C spread between the day's warmth and the night's chill. On most days the high lands between 31°C and 33°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)
13225
23225
33225
43225
53225
63225
73225
83225
93225
103225
113225
123225
133225
143225
153225
163225
173225
183225
193225
203225
213225
223225
233225
243225
253225
263225
273225
283225
293225
303225

How September really feels in Barreirinhas

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.

Barreirinhas weather by month

How September compares with the rest of the year at a glance. September is the 1st-warmest and 12th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan31° / 25°14021.612.13.4
Feb30° / 24°20424.212.13.1
Mar30° / 24°27829122.8
Apr30° / 24°30327.211.92.9
May30° / 25°19222.111.93.5
Jun31° / 25°6613.111.84.6
Jul31° / 25°386.811.95.1
Aug32° / 25°71.511.95.1
Sep32° / 25°30.8125.1
Oct32° / 25°60.812.15.1
Nov32° / 26°112.412.14.9
Dec32° / 25°378.412.24.4

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 83% of the time in September, the clearest month of the year.

Beyond those clear spells, partly cloudy skies cover about 11% of September, with mostly cloudy or overcast conditions the remaining 6%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
1964
2964
3964
4964
5964
6964
7964
8964
9964
10964
11955
12955
13946
14946
15946
16937
17937
18937
19937
20937
21937
22937
23937
24937
25937
26937
27937
28937
29937
30928

Chance of precipitation in September

Any precipitation

Barreirinhas gets around 3 mm of rain over 0.8 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 3% and peaks near 3% on the wettest days.

0%10%20%30%151015202530
Rain chance (%)
13
23
33
43
53
62
72
82
92
102
112
122
132
142
152
162
172
183
193
203
213
223
233
243
253
263
273
283
293
303

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 95% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

0%25%50%75%100%151015202530
Muggy (%)Oppressive (%)
1496
2595
3595
4595
5595
6694
7694
8694
9694
10694
11694
12694
13694
14694
15694
16694
17595
18595
19595
20595
21496
22496
23496
24496
25496
26397
27397
28397
29397
30397

Wind in September

Winds average 19 km/h in September.

Across September, daily wind ranges from about 18 km/h on the calmest days to 20 km/h at its breeziest. It stays fairly steady from day to day.

0510152025151015202530
Wind speed (km/h)Feels
118light breeze
218light breeze
318light breeze
418light breeze
518light breeze
618light breeze
719light breeze
819light breeze
919light breeze
1019light breeze
1119light breeze
1219light breeze
1319light breeze
1419light breeze
1519light breeze
1619light breeze
1719light breeze
1819light breeze
1919light breeze
2019light breeze
2119light breeze
2219light breeze
2319light breeze
2419light breeze
2519light breeze
2620light breeze
2720light breeze
2820light breeze
2920light breeze
3020light breeze

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 5:53 AM to 5:40 AM, and sunset from 5:49 PM to 5:41 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
111.95:535:49
211.95:525:49
312.05:525:49
412.05:515:49
512.05:515:48
612.05:515:48
712.05:505:48
812.05:505:48
912.05:495:47
1012.05:495:47
1112.05:485:47
1212.05:485:46
1312.05:475:46
1412.05:475:46
1512.05:475:45
1612.05:465:45
1712.05:465:45
1812.05:455:45
1912.05:455:44
2012.05:445:44
2112.05:445:44
2212.05:435:43
2312.05:435:43
2412.05:435:43
2512.05:425:43
2612.05:425:42
2712.05:415:42
2812.05:415:42
2912.05:405:42
3012.05:405:41

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 6.73 kWh/m².

For context, solar energy here swings from a low near 4.86 kWh/m² to a high of 6.8 kWh/m² in October across the year — September's 6.73 kWh/m² sits near the top of that range.

0246151015202530
Solar energy (kWh/m²)Level
16.5Intense
26.6Intense
36.6Intense
46.6Intense
56.6Intense
66.6Intense
76.7Intense
86.7Intense
96.7Intense
106.7Intense
116.7Intense
126.7Intense
136.7Intense
146.7Intense
156.7Intense
166.8Intense
176.8Intense
186.8Intense
196.8Intense
206.8Intense
216.8Intense
226.8Intense
236.8Intense
246.8Intense
256.8Intense
266.8Intense
276.8Intense
286.8Intense
296.8Intense
306.8Intense
Planning a trip in September

Hazard calendar for Barreirinhas

In seasonPeak

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

Barreirinhas's monsoon runs January–May, 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 Barreirinhas?

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

5.1
Sightseeing
1st-best month of the year
8.3
Beach & pool
1st-best month of the year

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

What to pack for Barreirinhas in September

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

In September, Barreirinhas sees daytime highs around 32°C and nights near 25°C. Pack light clothes and sun protection.

light clothessun protection

Sea temperature near Barreirinhas in September

The nearest coast averages about 27°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 27 km away) is warmest in April at about 29°C and coldest in September 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
Jan28Tropical
Feb28Tropical
Mar29Tropical
Apr29Tropical
May29Tropical
Jun29Tropical
Jul28Warm
Aug27Warm
Sep27Warm
Oct27Warm
Nov28Warm
Dec28Warm

UV index in Barreirinhas 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 Barreirinhas peaks around March 16 at about 16 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near July 15 at about 10 (extreme).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeMar 16UV 16Jul 15UV 10
UV index (midday)Level
Jan13Extreme
Feb14Extreme
Mar16Extreme
Apr14Extreme
May12Extreme
Jun10Extreme
Jul10Extreme
Aug11Extreme
Sep12Extreme
Oct12Extreme
Nov11Extreme
Dec12Extreme

Air quality in Barreirinhas 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 Barreirinhas is worst in July — around 20 µg/m³ PM2.5 (moderate), about 2.4× the cleanest month (May, 8 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecModerateGoodModerateGoodModerateJul 1719 µg/m³May 219 µg/m³
PM2.5 (µg/m³)Level
Jan12Moderate
Feb15Moderate
Mar14Moderate
Apr11Good
May8Good
Jun9Good
Jul20Moderate
Aug12Good
Sep9Good
Oct11Good
Nov14Moderate
Dec14Moderate
Location & terrain

Where is Barreirinhas?

Barreirinhas sits at 2.8°S, 42.8°W, 5 m above sea level, in Brazil. The nearest listed city is Paulino Neves, 33 km away.

Topography around Barreirinhas

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

Within 3 km, the terrain around Barreirinhas has only modest variations in elevation — a maximum elevation change of 25 m around an average of 8 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 76 m; within 80 km, only modest variations in elevation — a maximum elevation change of 138 m.

The land around Barreirinhas is covered by grassland (36%) and trees (29%) within 3 km, trees (46%) and grassland (20%) within 16 km, and trees (39%) and water (30%) within 80 km.

3 km
25 m
16 km
76 m
80 km
138 m
treesshrubsgrasslandartificial surfacesbare terrainwaterwetlandmangroves
September weather nearby: Paulino Neves 33 km · Tutóia 61 km · Humberto de Campos 73 km · São Bernardo 81 km · Urbano Santos 82 km · Santa Quitéria do Maranhão 87 km · Luzilândia 93 km · São Benedito do Rio Preto 101 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 Barreirinhas (-2.7556°, -42.8259°, elevation 5 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).