Açailândia weather in September

In September, Açailândia sees average daytime highs of 34°C and overnight lows near 23°C, with 14 mm of rain across 2.9 wet days and about 12 hours of daylight. It is the 1st-warmest and 10th-wettest month of the year here.

Day-to-day highs hold fairly steady near 34°C through the month. The sky is clear or mostly clear about 58% 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 Açailândia's 3rd-clearest and 2nd-windiest month. For the whole year in context, see Açailândia's year-round climate.

Daytime high
34°
1st warmest
Overnight low
23°
10th coldest
Rainfall
14 mm
2.9 wet days
Daylight
12 hours
6:05 AM – 6:04 PM
Cloud cover
41%
3rd clearest
Wind
9 km/h
2nd windiest
Solar energy
6.28 kWh/m²
Travel score
3.7
out of 10

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 34°C through the month.

A typical September day in Açailândia reaches about 34°C in the afternoon and slips back to 23°C overnight — a 11°C spread between the day's warmth and the night's chill. On most days the high lands between 32°C and 35°C. Set against its neighbours, September runs on par with August and on par with October.

20°25°30°35°40°151015202530
Avg high (°C)Avg low (°C)
13422
23422
33422
43422
53422
63422
73422
83422
93422
103422
113422
123422
133423
143423
153423
163423
173423
183423
193423
203423
213423
223423
233423
243423
253423
263423
273423
283423
293423
303423

How September really feels in Açailândia

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.

Açailândia weather by month

How September compares with the rest of the year at a glance. September is the 1st-warmest and 10th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan30° / 22°25527.412.32.9
Feb30° / 22°26025.212.22.9
Mar30° / 22°30028.8122.8
Apr30° / 22°21024.611.93.1
May31° / 22°1021511.84.0
Jun32° / 21°153.311.74.8
Jul33° / 21°91.711.74.5
Aug34° / 22°40.711.84.0
Sep34° / 23°142.9123.7
Oct33° / 23°417.212.13.6
Nov32° / 23°10114.512.23.5
Dec31° / 22°16621.512.33.3

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 58% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 24% of September, with mostly cloudy or overcast conditions the remaining 18%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
18614
28515
38515
48515
58515
68515
78515
88515
98515
108515
118515
128515
138515
148515
158515
168416
178317
188317
198119
208119
217921
227921
237921
247723
257723
267723
277624
287624
297426
307426

Chance of precipitation in September

Any precipitation

Açailândia gets around 14 mm of rain over 2.9 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 9% and peaks near 16% on the wettest days. The odds climb toward the end of the month.

0%10%20%30%151015202530
Rain chance (%)
15
25
35
46
56
66
76
86
97
107
117
127
138
148
158
168
179
189
1910
2010
2111
2212
2312
2413
2514
2614
2715
2815
2915
3016

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 62% of days. Sticky, muggy-or-worse air turns up on roughly 84% of them.

0%25%50%75%100%151015202530
Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
15215915
24216015
34215916
44215916
54215817
64215817
74215817
84205818
94205818
104195819
114195819
124185919
133176020
143166120
153156220
163136321
173126322
183116422
19296623
20286624
21276625
22266626
23266527
24156628
25156529
26146530
27146431
28136432
29036433
30036433

Wind in September

Winds average 9 km/h in September.

Across September, daily wind ranges from about 9 km/h on the calmest days to 9 km/h at its breeziest. It stays fairly steady from day to day.

051015151015202530
Wind speed (km/h)Feels
19calm
29calm
39calm
49calm
59calm
69calm
79calm
89calm
99calm
109calm
119calm
129calm
139calm
149calm
159calm
169calm
179calm
189calm
199calm
209calm
219calm
229calm
239calm
249calm
259calm
269calm
279calm
289calm
299calm
309calm

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 6:13 AM to 5:58 AM, and sunset from 6:07 PM to 6:00 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
111.96:136:07
211.96:126:07
311.96:126:06
411.96:116:06
511.96:116:06
611.96:106:06
711.96:106:06
811.96:096:05
911.96:096:05
1011.96:086:05
1112.06:086:05
1212.06:076:04
1312.06:076:04
1412.06:066:04
1512.06:066:04
1612.06:056:04
1712.06:056:03
1812.06:046:03
1912.06:046:03
2012.06:036:03
2112.06:036:02
2212.06:026:02
2312.06:026:02
2412.06:016:02
2512.06:016:01
2612.06:006:01
2712.06:006:01
2812.05:596:01
2912.05:596:01
3012.05:586:00

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 6.28 kWh/m² — the sunniest month for solar.

For context, solar energy here swings from a low near 4.47 kWh/m² to a high of 6.28 kWh/m² in September across the year — September's 6.28 kWh/m² sits near the top of that range.

0246151015202530
Solar energy (kWh/m²)Level
16.2Intense
26.2Intense
36.2Intense
46.2Intense
56.2Intense
66.2Intense
76.2Intense
86.3Intense
96.3Intense
106.3Intense
116.3Intense
126.3Intense
136.3Intense
146.3Intense
156.3Intense
166.3Intense
176.3Intense
186.3Intense
196.3Intense
206.3Intense
216.3Intense
226.3Intense
236.3Intense
246.3Intense
256.3Intense
266.3Intense
276.3Intense
286.3Intense
296.3Intense
306.3Intense
Planning a trip in September

Hazard calendar for Açailândia

In seasonPeak

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

Açailândia's monsoon runs December–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 Açailândia?

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

3.7
Sightseeing
5th-best month of the year
7.3
Beach & pool
4th-best month of the year

September is a weaker month for outdoor sightseeing in Açailândia. The water and warmth also suit a beach or pool day.

What to pack for Açailândia in September

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

In September, Açailândia sees daytime highs around 34°C and nights near 23°C. Pack light clothes and sun protection.

light clothessun protection

UV index in Açailândia 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 Açailândia peaks around March 11 at about 15 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near July 14 at about 10 (extreme).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeMar 11UV 15Jul 14UV 10
UV index (midday)Level
Jan13Extreme
Feb15Extreme
Mar15Extreme
Apr14Extreme
May11Extreme
Jun10Extreme
Jul10Extreme
Aug11Extreme
Sep12Extreme
Oct12Extreme
Nov11Extreme
Dec10Extreme

Air quality in Açailândia 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 Açailândia is worst in October — around 29 µg/m³ PM2.5 (moderate), about 4.9× the cleanest month (June, 6 µg/m³).

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

010203040JanFebMarAprMayJunJulAugSepOctNovDecModerateGoodModerateOct 2329 µg/m³Jun 206 µg/m³
PM2.5 (µg/m³)Level
Jan14Moderate
Feb13Moderate
Mar13Moderate
Apr12Moderate
May9Good
Jun6Good
Jul7Good
Aug12Moderate
Sep23Moderate
Oct29Moderate
Nov29Moderate
Dec20Moderate
Location & terrain

Where is Açailândia?

Açailândia sits at 4.9°S, 47.5°W, 243 m above sea level, in Brazil. The nearest listed city is Itinga do Maranhão, 55 km away.

Topography around Açailândia

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

Within 3 km, the terrain around Açailândia has only modest variations in elevation — a maximum elevation change of 148 m around an average of 239 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 258 m; within 80 km, significant variations in elevation — a maximum elevation change of 354 m.

The land around Açailândia is covered by grassland (54%) and artificial surfaces (27%) within 3 km, grassland (51%) and trees (43%) within 16 km, and grassland (55%) and trees (41%) within 80 km.

3 km
148 m
16 km
258 m
80 km
354 m
treesgrasslandcroplandartificial surfaces
September weather nearby: Itinga do Maranhão 55 km · João Lisboa 57 km · Imperatriz 64 km · Rondon do Pará 65 km · Dom Eliseu 74 km · Bom Jesus das Selvas 89 km · Governador Edison Lobão 90 km · Araguatins 103 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 Açailândia (-4.9467°, -47.5047°, elevation 243 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. 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).