Alto Alegre do Maranhão weather in September

In September, Alto Alegre do Maranhão sees average daytime highs of 35°C and overnight lows near 24°C, with 7 mm of rain across 1.3 wet days and about 12 hours of daylight. It is the 2nd-warmest and 11th-wettest month of the year here.

Day-to-day highs hold fairly steady near 35°C through the month. The sky is clear or mostly clear about 70% 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 Alto Alegre do Maranhão's 2nd-clearest and 2nd-windiest month. For the whole year in context, see Alto Alegre do Maranhão's year-round climate.

Daytime high
35°
2nd warmest
Overnight low
24°
9th coldest
Rainfall
7 mm
1.3 wet days
Daylight
12 hours
5:53 AM – 5:51 PM
Cloud cover
35%
2nd clearest
Wind
8 km/h
2nd windiest
Solar energy
6.3 kWh/m²
Travel score
3.0
out of 10

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 35°C through the month.

A typical September day in Alto Alegre do Maranhão reaches about 35°C in the afternoon and slips back to 24°C overnight — a 11°C spread between the day's warmth and the night's chill. On most days the high lands between 34°C and 37°C. Set against its neighbours, September runs about 1°C warmer than August and on par with October.

20°25°30°35°40°151015202530
Avg high (°C)Avg low (°C)
13524
23524
33524
43524
53524
63524
73524
83524
93524
103524
113524
123524
133524
143524
153524
163524
173524
183524
193524
203524
213524
223524
233524
243524
253624
263624
273624
283625
293625
303625

How September really feels in Alto Alegre do Maranhão

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
14 feel dangerously hot (≥ 39°C)
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.

Alto Alegre do Maranhão weather by month

How September compares with the rest of the year at a glance. September is the 2nd-warmest and 11th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan32° / 24°25125.112.22.6
Feb31° / 23°26324.812.12.6
Mar31° / 23°32829122.5
Apr31° / 23°27726.611.92.7
May31° / 23°13218.211.83.5
Jun32° / 23°346.611.84.5
Jul33° / 23°142.711.84.4
Aug34° / 23°5111.93.7
Sep35° / 24°71.3123.0
Oct36° / 25°14312.12.7
Nov35° / 25°457.112.22.7
Dec34° / 24°12614.612.22.7

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 70% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 21% of September, with mostly cloudy or overcast conditions the remaining 9%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
1937
2937
3937
4937
5928
6928
7928
8928
9928
10928
11928
12928
13928
14928
15928
16919
17919
18919
19919
209010
219010
229010
239010
249010
259010
269010
278911
288812
298812
308812

Chance of precipitation in September

Any precipitation

Alto Alegre do Maranhão gets around 7 mm of rain over 1.3 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 4% and peaks near 5% on the wettest days.

0%10%20%30%151015202530
Rain chance (%)
13
23
33
43
54
64
74
84
94
104
114
124
135
145
155
165
175
185
195
205
215
225
235
245
255
265
275
285
295
305

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 56% of days. Sticky, muggy-or-worse air turns up on roughly 96% of them.

0%25%50%75%100%151015202530
Humid (%)Muggy (%)Oppressive (%)
163856
263856
363955
463955
564054
664153
774152
874251
974251
1064252
1164252
1264351
1364351
1454253
1554253
1654253
1744254
1844155
1934156
2034057
2133958
2223959
2323860
2423860
2513762
2613762
2713663
2813663
2913663
3013663

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 9 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
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 6:00 AM to 5:46 AM, and sunset from 5:55 PM to 5:48 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
111.96:005:55
211.95:595:55
311.95:595:55
411.95:595:54
511.95:585:54
611.95:585:54
711.95:575:54
811.95:575:53
911.95:565:53
1012.05:565:53
1112.05:555:53
1212.05:555:52
1312.05:545:52
1412.05:545:52
1512.05:535:52
1612.05:535:51
1712.05:525:51
1812.05:525:51
1912.05:515:51
2012.05:515:50
2112.05:505:50
2212.05:505:50
2312.05:495:50
2412.05:495:49
2512.05:485:49
2612.05:485:49
2712.05:475:49
2812.05:475:49
2912.05:475:48
3012.05:465:48

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 6.3 kWh/m².

For context, solar energy here swings from a low near 4.37 kWh/m² to a high of 6.33 kWh/m² in October across the year — September's 6.3 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
86.2Intense
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
246.4Intense
256.4Intense
266.4Intense
276.4Intense
286.4Intense
296.4Intense
306.4Intense
Planning a trip in September

Hazard calendar for Alto Alegre do Maranhão

In seasonPeak

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

Alto Alegre do Maranhão'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 Alto Alegre do Maranhão?

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

3.0
Sightseeing
5th-best month of the year
6.6
Beach & pool
4th-best month of the year

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

What to pack for Alto Alegre do Maranhão in September

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

In September, Alto Alegre do Maranhão sees daytime highs around 35°C and nights near 24°C. Pack light clothes and sun protection.

light clothessun protection

UV index in Alto Alegre do Maranhão 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 Alto Alegre do Maranhão peaks around March 14 at about 15 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near August 10 at about 10 (very high).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeVery highExtremeMar 14UV 15Aug 10UV 10
UV index (midday)Level
Jan13Extreme
Feb14Extreme
Mar15Extreme
Apr14Extreme
May11Extreme
Jun10Extreme
Jul10Very high
Aug10Very high
Sep12Extreme
Oct12Extreme
Nov11Extreme
Dec11Extreme

Air quality in Alto Alegre do Maranhão 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 Alto Alegre do Maranhão is worst in October — around 35 µg/m³ PM2.5 (moderate), about 4.0× the cleanest month (June, 9 µg/m³).

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

010203040JanFebMarAprMayJunJulAugSepOctNovDecModerateGoodModerateOct 2134 µg/m³Jun 159 µg/m³
PM2.5 (µg/m³)Level
Jan15Moderate
Feb15Moderate
Mar14Moderate
Apr13Moderate
May10Good
Jun9Good
Jul11Good
Aug13Moderate
Sep19Moderate
Oct35Moderate
Nov30Moderate
Dec23Moderate
Location & terrain

Where is Alto Alegre do Maranhão?

Alto Alegre do Maranhão sits at 4.2°S, 44.4°W, 58 m above sea level, in Brazil. The nearest listed city is São Mateus do Maranhão, 19 km away.

Topography around Alto Alegre do Maranhão

How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Alto Alegre do Maranhão.

Within 3 km, the terrain around Alto Alegre do Maranhão has only modest variations in elevation — a maximum elevation change of 31 m around an average of 52 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 100 m; within 80 km, only modest variations in elevation — a maximum elevation change of 227 m.

The land around Alto Alegre do Maranhão is covered by trees (32%), grassland (32%) and shrubs (24%) within 3 km, grassland (43%) and trees (42%) within 16 km, and trees (48%) and grassland (46%) within 80 km.

3 km
31 m
16 km
100 m
80 km
227 m
treesshrubsgrasslandartificial surfaceswaterwetland
September weather nearby: São Mateus do Maranhão 19 km · Peritoró 23 km · São Luís Gonzaga do Maranhão 31 km · Coroatá 37 km · Bacabal 37 km · Pedreiras 43 km · Trizidela do Vale 44 km · Timbiras 56 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 Alto Alegre do Maranhão (-4.2128°, -44.4464°, elevation 58 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).