Cacoal weather in September

In September, Cacoal sees average daytime highs of 33°C and overnight lows near 22°C, with 90 mm of rain across 14.2 wet days and about 11.9 hours of daylight. It is the 2nd-warmest and 8th-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 38% 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 Cacoal's 4th-clearest and 4th-windiest month. For the whole year in context, see Cacoal's year-round climate.

Daytime high
33°
2nd warmest
Overnight low
22°
6th coldest
Rainfall
90 mm
14.2 wet days
Daylight
11 h 54 min
6:02 AM – 5:58 PM
Cloud cover
53%
4th clearest
Wind
6 km/h
4th windiest
Solar energy
5.8 kWh/m²
Travel score
3.1
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 Cacoal reaches about 33°C in the afternoon and slips back to 22°C overnight — a 11°C spread between the day's warmth and the night's chill. On most days the high lands between 30°C and 36°C. Set against its neighbours, September runs on par with August and about 1°C warmer than October.

15°20°25°30°35°40°151015202530
Avg high (°C)Avg low (°C)
13322
23322
33322
43322
53322
63322
73322
83322
93322
103322
113322
123322
133322
143322
153322
163322
173322
183322
193322
203322
213322
223322
233322
243322
253322
263322
273322
283323
293323
303323

How September really feels in Cacoal

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.

Cacoal weather by month

How September compares with the rest of the year at a glance. September is the 2nd-warmest and 8th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan29° / 22°30829.312.62.8
Feb29° / 22°29726.412.42.8
Mar30° / 22°27028.212.12.9
Apr30° / 22°15122.311.83.4
May30° / 21°7713.411.54.7
Jun31° / 20°173.511.35.5
Jul32° / 20°112.111.45.1
Aug33° / 21°264.811.64.0
Sep33° / 22°9014.211.93.1
Oct32° / 23°15721.812.32.8
Nov31° / 23°2392512.52.8
Dec30° / 23°28427.912.72.9

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 38% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 25% of September, with mostly cloudy or overcast conditions the remaining 37%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
17624
27525
37525
47426
57426
67327
77228
87228
97129
107030
117030
126931
136832
146634
156436
166337
176139
186040
195941
205842
215743
225644
235545
245347
255347
265248
275149
284951
294951
304951

Chance of precipitation in September

Any precipitation

Cacoal gets around 90 mm of rain over 14.2 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 47% and peaks near 64% on the wettest days. The odds climb toward the end of the month.

0%20%40%60%151015202530
Rain chance (%)
129
231
332
433
534
636
737
838
939
1040
1141
1242
1344
1445
1546
1648
1749
1850
1951
2053
2154
2255
2356
2458
2559
2660
2761
2862
2963
3064

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 58% of days. Sticky, muggy-or-worse air turns up on roughly 86% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
1471935360
2471835370
3371735380
4361635390
5361535410
6361435420
7261435430
8261334450
9261333460
10251233480
11151232500
12151131520
13151030540
14141029560
1514928580
1614827600
1704826620
1804726630
1903625660
2003624661
2103523681
2203522691
2303421711
2403420721
2502319751
2602318761
2702317771
2802216791
2902215792
3002215792

Wind in September

Winds average 6 km/h in September.

Across September, daily wind ranges from about 6 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
306calm

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 6:12 AM to 5:52 AM, and sunset from 5:59 PM to 5:58 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
111.86:125:59
211.86:125:59
311.86:115:59
411.86:105:59
511.86:105:59
611.86:095:59
711.86:085:59
811.96:085:59
911.96:075:59
1011.96:065:59
1111.96:055:58
1211.96:055:58
1311.96:045:58
1411.96:035:58
1511.96:035:58
1611.96:025:58
1711.96:015:58
1812.06:015:58
1912.06:005:58
2012.05:595:58
2112.05:595:58
2212.05:585:58
2312.05:575:58
2412.05:565:58
2512.05:565:58
2612.05:555:58
2712.15:545:58
2812.15:545:58
2912.15:535:58
3012.15:525:58

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 5.8 kWh/m².

For context, solar energy here swings from a low near 4.58 kWh/m² to a high of 5.88 kWh/m² in October across the year — September's 5.8 kWh/m² sits near the top of that range.

0246151015202530
Solar energy (kWh/m²)Level
15.7Bright
25.7Bright
35.7Bright
45.7Bright
55.7Bright
65.7Bright
75.7Bright
85.7Bright
95.8Bright
105.8Bright
115.8Bright
125.8Bright
135.8Bright
145.8Bright
155.8Bright
165.8Bright
175.8Bright
185.8Bright
195.8Bright
205.8Bright
215.8Bright
225.9Bright
235.9Bright
245.9Bright
255.9Bright
265.9Bright
275.9Bright
285.9Bright
295.9Bright
305.9Bright
Planning a trip in September

Hazard calendar for Cacoal

In seasonPeak

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

Cacoal's monsoon runs October–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 Cacoal?

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

3.1
Sightseeing
6th-best month of the year
5.7
Beach & pool
5th-best month of the year

September is a weaker month for outdoor sightseeing in Cacoal.

What to pack for Cacoal in September

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

In September, Cacoal sees daytime highs around 33°C and nights near 22°C. Pack light clothes and rain gear. Worth having: sun protection. About 14 days see rain.

light clothesrain gearsun protection

UV index in Cacoal in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 3 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Cacoal peaks around January 22 at about 15 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near September 14 at about 4 (moderate).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeVery highModerateExtremeJan 22UV 15Sep 14UV 4
UV index (midday)Level
Jan15Extreme
Feb15Extreme
Mar15Extreme
Apr13Extreme
May10Very high
Jun9Very high
Jul9Very high
Aug8Very high
Sep3Moderate
Oct11Extreme
Nov14Extreme
Dec14Extreme

Air quality in Cacoal 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 Cacoal is worst in September — around 53 µg/m³ PM2.5 (poor), about 6.8× the cleanest month (July, 8 µg/m³).

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

0204060JanFebMarAprMayJunJulAugSepOctNovDecGoodModeratePoorModerateSep 1550 µg/m³Jul 98 µg/m³
PM2.5 (µg/m³)Level
Jan12Good
Feb12Good
Mar12Good
Apr10Good
May9Good
Jun8Good
Jul8Good
Aug31Moderate
Sep53Poor
Oct21Moderate
Nov15Moderate
Dec13Moderate
Location & terrain

Where is Cacoal?

Cacoal sits at 11.4°S, 61.4°W, 197 m above sea level, in Brazil. The nearest listed city is Pimenta Bueno, 38 km away.

Topography around Cacoal

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

Within 3 km, the terrain around Cacoal has only modest variations in elevation — a maximum elevation change of 80 m around an average of 189 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 262 m; within 80 km, significant variations in elevation — a maximum elevation change of 434 m.

The land around Cacoal is covered by artificial surfaces (45%), trees (27%) and grassland (25%) within 3 km, grassland (68%) and trees (27%) within 16 km, and grassland (60%) and trees (39%) within 80 km.

3 km
80 m
16 km
262 m
80 km
434 m
treesgrasslandcroplandartificial surfaceswater
September weather nearby: Pimenta Bueno 38 km · Espigão dOeste 48 km · Rolim de Moura 56 km · Presidente Médici 58 km · Alta Floresta d'Oeste 81 km · Ji Paraná 83 km · Ouro Preto do Oeste 114 km · São Miguel do Guaporé 141 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 Cacoal (-11.4386°, -61.4472°, elevation 197 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).