Formosa weather in September

In September, Formosa sees average daytime highs of 31°C and overnight lows near 19°C, with 23 mm of rain across 3.8 wet days and about 11.9 hours of daylight. It is the 1st-warmest and 8th-wettest month of the year here.

Day-to-day highs hold fairly steady near 31°C through the month. The sky is clear or mostly clear about 56% of the time in September, and the air most often feels dry.

Daylight stretches from about 11 h 42 min at the start of September to 12 h 06 min by month's end. Set against the rest of the year, September is Formosa's 4th-clearest and 2nd-windiest month. For the whole year in context, see Formosa's year-round climate.

Daytime high
31°
1st warmest
Overnight low
19°
5th coldest
Rainfall
23 mm
3.8 wet days
Daylight
11 h 54 min
7:06 AM – 7:01 PM
Cloud cover
38%
4th clearest
Wind
8 km/h
2nd windiest
Solar energy
6.24 kWh/m²
Travel score
5.3
out of 10

Formosa 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 31°C through the month.

A typical September day in Formosa reaches about 31°C in the afternoon and slips back to 19°C overnight — a 12°C spread between the day's warmth and the night's chill. On most days the high lands between 28°C and 34°C. Set against its neighbours, September runs about 2°C warmer than August and on par with October.

15°20°25°30°35°151015202530
Avg high (°C)Avg low (°C)
13018
23018
33118
43118
53118
63118
73118
83118
93118
103118
113119
123119
133119
143119
153119
163119
173119
183119
193119
203119
213119
223119
233120
243120
253120
263120
273120
283120
293120
303120

Formosa weather by month

How September compares with the rest of the year at a glance. September is the 1st-warmest and 8th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan28° / 20°20218.612.84.5
Feb29° / 20°15916.512.54.5
Mar29° / 20°17418.312.14.6
Apr29° / 19°691011.75.7
May28° / 17°15311.37.3
Jun27° / 16°40.611.18.3
Jul28° / 15°0011.28.5
Aug29° / 17°41.111.57.1
Sep31° / 19°233.811.95.3
Oct31° / 20°10311.612.44.4
Nov29° / 20°21820.812.74.1
Dec28° / 20°24420.612.94.3

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 56% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 19% of September, with mostly cloudy or overcast conditions the remaining 26%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
18416
28416
38317
48317
58317
68218
78218
88218
98218
108020
118020
128020
137822
147822
157723
167624
177525
187327
197327
207129
217030
226832
236733
246634
256535
266337
276238
286238
296040
306040

Chance of precipitation in September

Any precipitation

Formosa gets around 23 mm of rain over 3.8 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 13% and peaks near 26% on the wettest days. The odds climb toward the end of the month.

0%10%20%30%40%151015202530
Rain chance (%)
16
26
36
46
56
66
76
86
96
107
118
128
139
1410
1511
1612
1713
1814
1915
2016
2117
2219
2320
2421
2522
2623
2724
2824
2925
3026

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, September lands in the dry band about 56% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)
1731881
2731881
3721891
4721891
5721891
6721891
77118101
87118101
97118101
107018111
116919111
126820111
136620122
146521122
156322132
165924143
175825143
185526154
195227165
205028176
214729186
224429197
234130218
243930229
253631249
2634312510
2732312611
2831302712
2929302812
3028292913

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
19calm
29calm
39calm
49calm
59calm
69calm
79calm
89calm
99calm
109calm
119calm
129calm
139calm
149calm
159calm
169calm
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 42 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 24 minutes over September. Sunrise moves from 7:18 AM to 6:55 AM, and sunset from 7:00 PM to 7:02 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
111.77:187:00
211.77:177:00
311.77:177:00
411.77:167:00
511.87:157:00
611.87:147:00
711.87:147:00
811.87:137:00
911.87:127:01
1011.87:117:01
1111.87:107:01
1211.97:107:01
1311.97:097:01
1411.97:087:01
1511.97:077:01
1611.97:067:01
1711.97:057:01
1811.97:057:01
1912.07:047:01
2012.07:037:01
2112.07:027:01
2212.07:017:02
2312.07:017:02
2412.07:007:02
2512.06:597:02
2612.16:587:02
2712.16:577:02
2812.16:577:02
2912.16:567:02
3012.16:557:02

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 6.24 kWh/m² — the sunniest month for solar.

For context, solar energy here swings from a low near 4.62 kWh/m² to a high of 6.24 kWh/m² in September across the year — September's 6.24 kWh/m² sits near the top of that range.

0246151015202530
Solar energy (kWh/m²)Level
16.0Intense
26.1Intense
36.1Intense
46.1Intense
56.2Intense
66.2Intense
76.2Intense
86.2Intense
96.2Intense
106.2Intense
116.3Intense
126.3Intense
136.3Intense
146.3Intense
156.3Intense
166.3Intense
176.3Intense
186.3Intense
196.2Intense
206.2Intense
216.2Intense
226.2Intense
236.2Intense
246.2Intense
256.2Intense
266.2Intense
276.2Intense
286.2Intense
296.3Intense
306.3Intense
Planning a trip in September

Hazard calendar for Formosa

In seasonPeak

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

Formosa'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 Formosa?

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

5.3
Sightseeing
6th-best month of the year
7.8
Beach & pool
5th-best month of the year

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

What to pack for Formosa in September

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

In September, Formosa sees daytime highs around 31°C and nights near 19°C. Pack light clothes and sun protection. About 4 days see rain.

light clothessun protection

UV index in Formosa 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 Formosa peaks around February 15 at about 16 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near July 10 at about 8 (very high).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeVery highExtremeFeb 15UV 16Jul 10UV 8
UV index (midday)Level
Jan15Extreme
Feb16Extreme
Mar15Extreme
Apr12Extreme
May10Very high
Jun8Very high
Jul8Very high
Aug10Very high
Sep12Extreme
Oct13Extreme
Nov14Extreme
Dec13Extreme

Air quality in Formosa 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 Formosa is worst in September — around 24 µg/m³ PM2.5 (moderate), about 3.5× the cleanest month (July, 7 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodSep 1923 µg/m³Jul 127 µg/m³
PM2.5 (µg/m³)Level
Jan8Good
Feb9Good
Mar10Good
Apr10Good
May9Good
Jun8Good
Jul7Good
Aug10Good
Sep24Moderate
Oct17Moderate
Nov9Good
Dec9Good
Location & terrain

Where is Formosa?

Formosa sits at 15.5°S, 47.3°W, 915 m above sea level, in Brazil. The nearest listed city is Planaltina, 31 km away.

Topography around Formosa

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

Within 3 km, the terrain around Formosa has only modest variations in elevation — a maximum elevation change of 176 m around an average of 917 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 610 m; within 80 km, large variations in elevation — a maximum elevation change of 848 m.

The land around Formosa is covered by artificial surfaces (47%) and grassland (25%) within 3 km, grassland (34%), trees (24%) and cropland (20%) within 16 km, and grassland (34%), trees (23%) and cropland (22%) within 80 km.

3 km
176 m
16 km
610 m
80 km
848 m
treesshrubsgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Planaltina 31 km · Planaltina 35 km · Sobradinho 51 km · Itapoã 52 km · Sobradinho II 55 km · Paranoá 55 km · Lago Norte 60 km · São Sebastião 62 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 Formosa (-15.5372°, -47.3344°, elevation 915 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).