Três Rios weather in September

In September, Três Rios sees average daytime highs of 26°C and overnight lows near 16°C, with 59 mm of rain across 8.7 wet days and about 11.9 hours of daylight. It is the 8th-warmest and 7th-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 33% of the time in September, and the air most often feels comfortable.

Daylight stretches from about 11 h 36 min at the start of September to 12 h 12 min by month's end. Set against the rest of the year, September is Três Rios's 5th-clearest and 1st-windiest month. For the whole year in context, see Três Rios's year-round climate.

Daytime high
26°
8th warmest
Overnight low
16°
5th coldest
Rainfall
59 mm
8.7 wet days
Daylight
11 h 54 min
6:51 AM – 6:43 PM
Cloud cover
59%
5th clearest
Wind
8 km/h
1st windiest
Solar energy
4.64 kWh/m²
Travel score
6.8
out of 10

Três Rios 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 Três Rios reaches about 26°C in the afternoon and slips back to 16°C overnight — a 10°C spread between the day's warmth and the night's chill. On most days the high lands between 21°C and 31°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)
12615
22615
32615
42615
52616
62616
72616
82616
92616
102616
112616
122616
132616
142616
152616
162616
172616
182616
192616
202616
212617
222617
232617
242617
252617
262617
272617
282617
292617
302617

Três Rios weather by month

How September compares with the rest of the year at a glance. September is the 8th-warmest and 7th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan29° / 20°23319.513.24.1
Feb30° / 20°15415.112.84.3
Mar29° / 20°14817.712.24.5
Apr27° / 18°579.611.56.4
May25° / 16°356.3117.4
Jun24° / 14°173.410.78.2
Jul24° / 14°183.710.88.2
Aug25° / 14°214.211.27.9
Sep26° / 16°598.711.96.8
Oct27° / 18°10713.712.55.8
Nov27° / 19°19818.813.14.8
Dec29° / 20°23621.313.34.2

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 33% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 14% of September, with mostly cloudy or overcast conditions the remaining 54%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
16238
26238
36139
46139
55941
65842
75743
85545
95446
105248
115149
124951
134852
144654
154654
164456
174258
184159
194159
204060
213862
223862
233763
243664
253565
263565
273664
283565
293466
303466

Chance of precipitation in September

Any precipitation

Três Rios gets around 59 mm of rain over 8.7 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 29% and peaks near 40% on the wettest days. The odds climb toward the end of the month.

0%10%20%30%40%50%151015202530
Rain chance (%)
119
219
320
420
520
621
721
822
923
1024
1125
1225
1326
1427
1528
1629
1730
1831
1932
2033
2134
2235
2336
2436
2537
2638
2738
2839
2939
3040

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, September lands in the comfortable band about 43% of days. Sticky, muggy-or-worse air turns up on roughly 7% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)
12647252
22547262
32447262
42448272
52348272
62248282
72148292
82048293
91948303
101848313
111748323
121548334
131447344
141347354
151346365
161246375
171145386
181144396
191143397
201042408
211041409
2210404110
2310384111
2410374112
259364213
269354214
279334215
289324316
299314317
309304318

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 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
99calm
109calm
119calm
129calm
139calm
149calm
159calm
169calm
179calm
189calm
199calm
209calm
219calm
229calm
239calm
249calm
258calm
268calm
278calm
288calm
298calm
308calm

Sunrise & sunset in September

DaylightNight

Daylight runs from about 11 h 36 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 36 minutes over September. Sunrise moves from 7:06 AM to 6:37 AM, and sunset from 6:39 PM to 6:48 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
111.67:066:39
211.67:056:39
311.67:046:40
411.67:036:40
511.67:026:40
611.77:016:41
711.77:006:41
811.76:596:41
911.76:586:41
1011.76:576:42
1111.86:566:42
1211.86:556:42
1311.86:546:43
1411.86:536:43
1511.96:526:43
1611.96:516:43
1711.96:506:44
1811.96:496:44
1911.96:486:44
2012.06:476:45
2112.06:466:45
2212.06:456:45
2312.06:446:45
2412.06:436:46
2512.16:426:46
2612.16:416:46
2712.16:406:47
2812.16:396:47
2912.26:386:47
3012.26:376:48

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.64 kWh/m².

For context, solar energy here swings from a low near 3.41 kWh/m² to a high of 5.9 kWh/m² in February across the year — September's 4.64 kWh/m² falls in the middle.

024151015202530
Solar energy (kWh/m²)Level
14.6Bright
24.7Bright
34.7Bright
44.7Bright
54.7Bright
64.7Bright
74.7Bright
84.7Bright
94.7Bright
104.7Bright
114.7Bright
124.7Bright
134.7Bright
144.7Bright
154.6Bright
164.6Bright
174.6Bright
184.6Bright
194.6Bright
204.6Bright
214.6Bright
224.6Bright
234.6Bright
244.6Bright
254.6Bright
264.6Bright
274.6Bright
284.6Bright
294.6Bright
304.7Bright
Planning a trip in September

Hazard calendar for Três Rios

In seasonPeak

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

Três Rios's monsoon runs October–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 Três Rios?

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

6.8
Sightseeing
5th-best month of the year
6.6
Beach & pool
6th-best month of the year

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

What to pack for Três Rios in September

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

In September, Três Rios sees daytime highs around 26°C and nights near 16°C. Worth packing: light clothes, rain gear and sun protection. About 9 days see rain.

light clothesrain gearsun protection

UV index in Três Rios in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 8 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Três Rios peaks around February 9 at about 15 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near July 10 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 highExtremeFeb 9UV 15Jul 10UV 6
UV index (midday)Level
Jan15Extreme
Feb15Extreme
Mar13Extreme
Apr10Very high
May7High
Jun6High
Jul6High
Aug8Very high
Sep8Very high
Oct12Extreme
Nov14Extreme
Dec14Extreme

Air quality in Três Rios 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 Três Rios is worst in September — around 22 µg/m³ PM2.5 (moderate), about 2.0× the cleanest month (January, 11 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodSep 1521 µg/m³Jan 1111 µg/m³
PM2.5 (µg/m³)Level
Jan11Good
Feb11Good
Mar12Good
Apr13Moderate
May15Moderate
Jun15Moderate
Jul14Moderate
Aug16Moderate
Sep22Moderate
Oct14Moderate
Nov12Good
Dec11Good
Location & terrain

Where is Três Rios?

Três Rios sits at 22.1°S, 43.2°W, 276 m above sea level, in Brazil. The nearest listed city is Paraíba do Sul, 10 km away.

Topography around Três Rios

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

Within 3 km, the terrain around Três Rios has significant variations in elevation — a maximum elevation change of 408 m around an average of 338 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 655 m; within 80 km, very significant variations in elevation — a maximum elevation change of 2,252 m.

The land around Três Rios is covered by grassland (52%), trees (24%) and artificial surfaces (22%) within 3 km, grassland (59%) and trees (37%) within 16 km, and trees (49%) and grassland (45%) within 80 km.

3 km
408 m
16 km
655 m
80 km
2,252 m
treesgrasslandartificial surfaceswater
September weather nearby: Paraíba do Sul 10 km · São José do Vale do Rio Preto 30 km · Sapucaia 33 km · Paty do Alferes 41 km · Teresópolis 41 km · Juiz de Fora 42 km · São Pedro 42 km · Petrópolis 43 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 Três Rios (-22.1167°, -43.2092°, elevation 276 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).