Boca do Acre weather in September

In September, Boca do Acre sees average daytime highs of 32°C and overnight lows near 23°C, with 98 mm of rain across 15.5 wet days and about 11.9 hours of daylight. It is the 1st-warmest and 9th-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 26% of the time in September, and the air most often feels oppressive.

Daylight stretches from about 11 h 48 min at the start of September to 12 h 06 min by month's end. Set against the rest of the year, September is Boca do Acre's 4th-clearest and 2nd-windiest month. For the whole year in context, see Boca do Acre's year-round climate.

Daytime high
32°
1st warmest
Overnight low
23°
5th coldest
Rainfall
98 mm
15.5 wet days
Daylight
12 hours
6:25 AM – 6:22 PM
Cloud cover
60%
4th clearest
Wind
6 km/h
2nd windiest
Solar energy
5.53 kWh/m²
Travel score
3.5
out of 10

Boca do Acre is human settlement in 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 Boca do Acre reaches about 32°C in the afternoon and slips back to 23°C overnight — a 9°C spread between the day's warmth and the night's chill. On most days the high lands between 29°C and 34°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)
13223
23223
33223
43223
53223
63223
73223
83223
93223
103223
113223
123223
133223
143223
153223
163223
173223
183223
193223
203223
213223
223223
233223
243223
253223
263223
273223
283223
293223
303223

How September really feels in Boca do Acre

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.

Boca do Acre weather by month

How September compares with the rest of the year at a glance. September is the 1st-warmest and 9th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan30° / 23°26827.912.52.8
Feb30° / 23°26525.612.32.8
Mar30° / 23°27428.512.12.7
Apr30° / 23°1982511.83.0
May30° / 22°11719.611.63.9
Jun30° / 22°4910.511.55.1
Jul30° / 21°336.311.55.6
Aug31° / 22°508.711.74.6
Sep32° / 23°9815.511.93.5
Oct32° / 23°16221.912.23.0
Nov31° / 23°21724.512.42.8
Dec30° / 23°26827.812.52.7

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 26% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 23% of September, with mostly cloudy or overcast conditions the remaining 51%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
16238
26040
35941
45842
55743
65743
75545
85446
95446
105347
115248
125248
135149
145050
155050
164951
174753
184654
194753
204654
214456
224456
234456
244258
254159
264159
274060
284060
293961
303763

Chance of precipitation in September

Any precipitation

Boca do Acre gets around 98 mm of rain over 15.5 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 52% and peaks near 62% on the wettest days. The odds climb toward the end of the month.

0%20%40%60%151015202530
Rain chance (%)
140
241
341
442
543
644
745
845
946
1047
1148
1249
1350
1451
1552
1653
1753
1854
1955
2056
2157
2257
2358
2459
2559
2660
2761
2861
2962
3062

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 70% of days. Sticky, muggy-or-worse air turns up on roughly 96% of them.

0%25%50%75%100%151015202530
Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
124117112
224107212
324107113
424107113
52497213
62397313
72397214
82387314
92387314
101387315
111387216
121277317
131277317
141277218
151277119
161277020
171276921
181266922
191266823
201266724
210266725
220266725
230256726
240256726
250256726
260246727
270246727
280246727
290246628
300246628

Wind in September

Winds average 6 km/h in September.

Across September, daily wind ranges from about 5 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
305calm

Sunrise & sunset in September

DaylightNight

Daylight runs from about 11 h 48 min at the start of September to 12 h 06 min by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 18 minutes over September. Sunrise moves from 6:34 AM to 6:17 AM, and sunset from 6:24 PM to 6:21 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
111.86:346:24
211.86:346:24
311.86:336:24
411.96:336:24
511.96:326:24
611.96:316:24
711.96:316:24
811.96:306:23
911.96:306:23
1011.96:296:23
1111.96:286:23
1211.96:286:23
1311.96:276:23
1411.96:276:23
1511.96:266:23
1612.06:256:22
1712.06:256:22
1812.06:246:22
1912.06:236:22
2012.06:236:22
2112.06:226:22
2212.06:226:22
2312.06:216:22
2412.06:206:22
2512.06:206:21
2612.06:196:21
2712.06:196:21
2812.16:186:21
2912.16:176:21
3012.16:176:21

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 5.53 kWh/m² — the sunniest month for solar.

For context, solar energy here swings from a low near 4.18 kWh/m² to a high of 5.53 kWh/m² in September across the year — September's 5.53 kWh/m² sits near the top of that range.

0246151015202530
Solar energy (kWh/m²)Level
15.5Bright
25.5Bright
35.5Bright
45.5Bright
55.5Bright
65.5Bright
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
215.6Bright
225.6Bright
235.6Bright
245.6Bright
255.6Bright
265.6Bright
275.6Bright
285.6Bright
295.5Bright
305.5Bright
Planning a trip in September

Hazard calendar for Boca do Acre

In seasonPeak

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

Boca do Acre's rainy season runs October–April, when most of the year's rain falls.

Rainy season
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Is September a good time to visit Boca do Acre?

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

3.5
Sightseeing
5th-best month of the year
5.6
Beach & pool
4th-best month of the year

September is a weaker month for outdoor sightseeing in Boca do Acre.

What to pack for Boca do Acre in September

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

In September, Boca do Acre sees daytime highs around 32°C and nights near 23°C. Pack light clothes and rain gear. Worth having: sun protection. About 16 days see rain.

light clothesrain gearsun protection

UV index in Boca do Acre in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 5 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Boca do Acre peaks around January 21 at about 15 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near September 9 at about 5 (moderate).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeVery highModerateExtremeJan 21UV 15Sep 9UV 5
UV index (midday)Level
Jan15Extreme
Feb15Extreme
Mar15Extreme
Apr13Extreme
May11Extreme
Jun9Very high
Jul9Very high
Aug5Moderate
Sep5Moderate
Oct12Extreme
Nov13Extreme
Dec13Extreme

Air quality in Boca do Acre 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 Boca do Acre is worst in September — around 110 µg/m³ PM2.5 (unhealthy), about 13.6× the cleanest month (June, 8 µg/m³).

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

0306090120JanFebMarAprMayJunJulAugSepOctNovDecModerateGoodModerateUnhealthyModerateSep 12106 µg/m³Jun 108 µg/m³
PM2.5 (µg/m³)Level
Jan13Moderate
Feb13Moderate
Mar13Moderate
Apr11Good
May9Good
Jun8Good
Jul15Moderate
Aug87Unhealthy
Sep110Unhealthy
Oct28Moderate
Nov14Moderate
Dec12Good
Location & terrain

Where is Boca do Acre?

Boca do Acre sits at 8.8°S, 67.4°W, 107 m above sea level, in Brazil. The nearest listed city is Porto Acre, 94 km away.

Riberalta

Topography around Boca do Acre

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

Within 3 km, the terrain around Boca do Acre has only modest variations in elevation — a maximum elevation change of 76 m around an average of 118 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 92 m; within 80 km, only modest variations in elevation — a maximum elevation change of 140 m.

The land around Boca do Acre is covered by trees (71%) within 3 km, trees (79%) within 16 km, and trees (88%) within 80 km.

3 km
76 m
16 km
92 m
80 km
140 m
treesgrasslandartificial surfaceswater
September weather nearby: Porto Acre 94 km · Pauini 124 km · Rio Branco 143 km · Sena Madureira 144 km · Senador Guiomard 160 km · Plácido de Castro 178 km · Xapuri 244 km · Riberalta 291 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 Boca do Acre (-8.7522°, -67.3978°, elevation 107 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).