Barra do Piraí weather in September

In September, Barra do Piraí sees average daytime highs of 26°C and overnight lows near 17°C, with 66 mm of rain across 10 wet days and about 11.9 hours of daylight. It is the 8th-warmest and 8th-wettest month of the year here.

Day-to-day highs hold fairly steady near 26°C through the month. The sky is clear or mostly clear about 35% of the time in September, and the air most often feels humid.

Daylight stretches from about 11 h 30 min at the start of September to 12 h 12 min by month's end. Set against the rest of the year, September is Barra do Piraí's 6th-clearest and 1st-windiest month. For the whole year in context, see Barra do Piraí's year-round climate.

Daytime high
26°
8th warmest
Overnight low
17°
5th coldest
Rainfall
66 mm
10 wet days
Daylight
11 h 54 min
6:53 AM – 6:46 PM
Cloud cover
59%
6th clearest
Wind
8 km/h
1st windiest
Solar energy
4.51 kWh/m²
Travel score
6.6
out of 10

Barra do Piraí 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 26°C through the month.

A typical September day in Barra do Piraí reaches about 26°C in the afternoon and slips back to 17°C overnight — a 9°C spread between the day's warmth and the night's chill. On most days the high lands between 20°C and 32°C. Set against its neighbours, September runs about 1°C warmer than August and about 1°C cooler than October.

10°15°20°25°30°35°151015202530
Avg high (°C)Avg low (°C)
12616
22616
32616
42616
52616
62616
72616
82616
92617
102617
112617
122617
132617
142617
152617
162617
172617
182617
192617
202617
212617
222617
232617
242617
252617
262617
272617
282617
292617
302617

How September really feels in Barra do Piraí

Once humidity and wind are folded in, September averages 0 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
0
heat index over the day's high
Days feeling ≤ C
0
wind chill below the day's low

September sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.

Barra do Piraí weather by month

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

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan30° / 21°2822213.23.7
Feb30° / 21°20017.612.83.9
Mar29° / 20°19520.312.24.2
Apr27° / 19°8912.511.56.0
May25° / 16°539.310.97.0
Jun25° / 15°285.510.77.8
Jul24° / 15°295.310.87.9
Aug25° / 15°275.511.27.7
Sep26° / 17°661011.96.6
Oct27° / 18°11214.112.55.7
Nov27° / 19°20219.313.14.8
Dec29° / 20°24922.213.44.1

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 35% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 11% of September, with mostly cloudy or overcast conditions the remaining 55%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
16040
26040
36040
45941
55842
65644
75545
85446
95347
105149
114951
124852
134753
144654
154555
164456
174357
184258
194060
203961
213862
223763
233763
243664
253565
263565
273565
283466
293466
303466

Chance of precipitation in September

Any precipitation

Barra do Piraí gets around 66 mm of rain over 10 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 33% and peaks near 43% on the wettest days. The odds climb toward the end of the month.

0%10%20%30%40%50%151015202530
Rain chance (%)
123
224
325
425
526
627
727
828
928
1029
1129
1229
1330
1430
1531
1631
1732
1833
1934
2035
2136
2237
2338
2439
2540
2641
2742
2843
2943
3043

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

Most of September feels humid — the stacked bands show each day's mix of comfort levels, read off the dew point.

By dew point, September lands in the humid band about 42% of days. Sticky, muggy-or-worse air turns up on roughly 12% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)
11743364
21642374
31642375
41542385
51542385
61541396
71441396
81440406
91340416
101240417
111139427
121039438
131039438
14939449
15838449
168384410
177384411
187374412
197364413
207364414
217354315
227344316
236334318
246324319
256314320
266304221
276294322
286284323
296274324
306264325

Wind in September

Winds average 8 km/h in September, the windiest month of the year.

Across September, daily wind ranges from about 8 km/h on the calmest days to 8 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
168calm
178calm
188calm
198calm
208calm
218calm
228calm
238calm
248calm
258calm
268calm
278calm
288calm
298calm
308calm

Sunrise & sunset in September

DaylightNight

Daylight runs from about 11 h 30 min at the start of September to 12 h 12 min by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 42 minutes over September. Sunrise moves from 7:09 AM to 6:39 AM, and sunset from 6:41 PM to 6:50 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
111.57:096:41
211.67:086:42
311.67:076:42
411.67:066:42
511.67:056:43
611.77:046:43
711.77:036:43
811.77:026:43
911.77:016:44
1011.77:006:44
1111.86:596:44
1211.86:586:45
1311.86:576:45
1411.86:566:45
1511.96:546:45
1611.96:536:46
1711.96:526:46
1811.96:516:46
1911.96:506:47
2012.06:496:47
2112.06:486:47
2212.06:476:48
2312.06:466:48
2412.16:456:48
2512.16:446:48
2612.16:436:49
2712.16:426:49
2812.16:416:49
2912.26:406:50
3012.26:396:50

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.51 kWh/m².

For context, solar energy here swings from a low near 3.36 kWh/m² to a high of 5.8 kWh/m² in February across the year — September's 4.51 kWh/m² falls in the middle.

024151015202530
Solar energy (kWh/m²)Level
14.5Bright
24.6Bright
34.6Bright
44.6Bright
54.6Bright
64.6Bright
74.6Bright
84.6Bright
94.6Bright
104.6Bright
114.6Bright
124.6Bright
134.5Bright
144.5Bright
154.5Bright
164.5Bright
174.5Bright
184.5Bright
194.5Bright
204.5Bright
214.5Bright
224.5Bright
234.5Bright
244.5Bright
254.5Bright
264.5Bright
274.5Bright
284.5Bright
294.5Bright
304.6Bright
Planning a trip in September

Hazard calendar for Barra do Piraí

In seasonPeak

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

Barra do Piraí's monsoon runs November–March, 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 Barra do Piraí?

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

6.6
Sightseeing
5th-best month of the year
6.4
Beach & pool
4th-best month of the year

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

What to pack for Barra do Piraí in September

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

In September, Barra do Piraí sees daytime highs around 26°C and nights near 17°C. Worth packing: light clothes, rain gear and sun protection. About 10 days see rain.

light clothesrain gearsun protection

UV index in Barra do Piraí in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 7 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Barra do Piraí peaks around January 24 at about 15 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near July 12 at about 6 (high).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeVery highHighVery highExtremeJan 24UV 15Jul 12UV 6
UV index (midday)Level
Jan15Extreme
Feb15Extreme
Mar12Extreme
Apr10Very high
May7High
Jun6High
Jul5High
Aug8Very high
Sep7High
Oct12Extreme
Nov14Extreme
Dec14Extreme

Air quality in Barra do Piraí 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 Barra do Piraí is worst in July — around 38 µg/m³ PM2.5 (poor), about 2.0× the cleanest month (December, 19 µg/m³).

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

010203040JanFebMarAprMayJunJulAugSepOctNovDecModeratePoorModerateModerateJul 1237 µg/m³Dec 2319 µg/m³
PM2.5 (µg/m³)Level
Jan19Moderate
Feb19Moderate
Mar21Moderate
Apr24Moderate
May31Moderate
Jun36Poor
Jul38Poor
Aug32Moderate
Sep37Poor
Oct24Moderate
Nov20Moderate
Dec19Moderate
Location & terrain

Where is Barra do Piraí?

Barra do Piraí sits at 22.5°S, 43.8°W, 366 m above sea level, in Brazil. The nearest listed city is Mendes, 11 km away.

Topography around Barra do Piraí

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

Within 3 km, the terrain around Barra do Piraí has significant variations in elevation — a maximum elevation change of 273 m around an average of 429 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 789 m; within 80 km, very significant variations in elevation — a maximum elevation change of 2,208 m.

The land around Barra do Piraí is covered by grassland (53%) and trees (27%) within 3 km, grassland (50%) and trees (48%) within 16 km, and trees (46%) and grassland (38%) within 80 km.

3 km
273 m
16 km
789 m
80 km
2,208 m
treesgrasslandartificial surfaceswater
September weather nearby: Mendes 11 km · Vassouras 18 km · Pinheiral 19 km · Piraí 19 km · Paracambi 19 km · Japeri 26 km · Valença 28 km · Volta Redonda 29 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 Barra do Piraí (-22.47°, -43.8256°, elevation 366 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).