Atibaia weather in September

In September, Atibaia sees average daytime highs of 25°C and overnight lows near 15°C, with 82 mm of rain across 8.9 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 25°C through the month. The sky is clear or mostly clear about 42% of the time in September, and the air most often feels comfortable.

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 Atibaia's 4th-clearest and 1st-windiest month. For the whole year in context, see Atibaia's year-round climate.

Daytime high
25°
8th warmest
Overnight low
15°
5th coldest
Rainfall
82 mm
8.9 wet days
Daylight
11 h 54 min
7:04 AM – 6:57 PM
Cloud cover
52%
4th clearest
Wind
10 km/h
1st windiest
Solar energy
5.13 kWh/m²
Travel score
7.1
out of 10

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 25°C through the month.

A typical September day in Atibaia reaches about 25°C in the afternoon and slips back to 15°C overnight — a 11°C spread between the day's warmth and the night's chill. On most days the high lands between 20°C and 30°C. Set against its neighbours, September runs about 1°C warmer than August and on par with October.

10°15°20°25°30°35°151015202530
Avg high (°C)Avg low (°C)
12513
22514
32514
42514
52514
62514
72514
82514
92514
102514
112514
122514
132515
142515
152515
162515
172515
182515
192515
202515
212515
222515
232515
242515
252515
262515
272515
282515
292515
302515

Atibaia 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
Jan27° / 19°24422.713.34.5
Feb27° / 19°18419.412.84.7
Mar27° / 18°15018.312.25.3
Apr25° / 16°649.411.56.9
May23° / 14°61710.97.4
Jun22° / 12°424.710.67.8
Jul22° / 12°434.210.77.9
Aug24° / 12°334.211.28.2
Sep25° / 15°828.911.97.1
Oct26° / 16°12214.112.56.0
Nov26° / 17°15616.313.15.5
Dec27° / 18°19220.613.44.8

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 42% 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 44%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
16931
26832
36733
46634
56535
66436
76337
86238
96139
106040
115941
125842
135842
145743
155644
165644
175644
185446
195347
205248
215248
225050
234951
244852
254753
264555
274555
284555
294357
304357

Chance of precipitation in September

Any precipitation

Atibaia gets around 82 mm of rain over 8.9 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 42% on the wettest days. The odds climb toward the end of the month.

0%10%20%30%40%50%151015202530
Rain chance (%)
120
220
321
421
522
622
723
823
923
1024
1124
1224
1325
1426
1526
1627
1728
1829
1930
2032
2133
2234
2336
2437
2538
2639
2740
2841
2942
3042

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 42% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)
1603460
2583570
3573670
4553780
5543880
6523990
75040100
84841100
94642110
104543120
114344130
124144140
134045150
143846160
153746170
163646180
173546190
183446200
193346210
203246220
213145231
223045251
232944261
242844281
252743291
262642301
272542321
282441331
292340352
302339362

Wind in September

Winds average 10 km/h in September, the windiest month of the year.

Across September, daily wind ranges from about 10 km/h on the calmest days to 11 km/h at its breeziest. It stays fairly steady from day to day.

051015151015202530
Wind speed (km/h)Feels
110calm
210calm
310calm
410calm
510calm
610calm
710calm
810calm
910calm
1010calm
1110calm
1210calm
1310calm
1410calm
1510calm
1610calm
1711calm
1811calm
1911calm
2011calm
2111calm
2211calm
2311calm
2411calm
2511calm
2611calm
2711calm
2811calm
2911calm
3011calm

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 7:20 AM to 6:50 AM, and sunset from 6:52 PM to 7:01 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
111.57:206:52
211.67:196:52
311.67:186:52
411.67:176:53
511.67:166:53
611.67:156:53
711.77:146:54
811.77:136:54
911.77:126:54
1011.77:116:55
1111.87:106:55
1211.87:096:55
1311.87:086:56
1411.87:076:56
1511.87:066:56
1611.97:046:57
1711.97:036:57
1811.97:026:57
1911.97:016:58
2012.07:006:58
2112.06:596:58
2212.06:586:58
2312.06:576:59
2412.16:566:59
2512.16:556:59
2612.16:547:00
2712.16:537:00
2812.16:527:00
2912.26:517:01
3012.26:507:01

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 5.13 kWh/m².

For context, solar energy here swings from a low near 3.58 kWh/m² to a high of 5.67 kWh/m² in November across the year — September's 5.13 kWh/m² falls in the middle.

0246151015202530
Solar energy (kWh/m²)Level
15.1Bright
25.1Bright
35.1Bright
45.1Bright
55.1Bright
65.1Bright
75.1Bright
85.1Bright
95.1Bright
105.1Bright
115.1Bright
125.1Bright
135.1Bright
145.2Bright
155.2Bright
165.2Bright
175.2Bright
185.2Bright
195.2Bright
205.2Bright
215.2Bright
225.2Bright
235.2Bright
245.2Bright
255.2Bright
265.2Bright
275.2Bright
285.2Bright
295.2Bright
305.2Bright
Planning a trip in September

Hazard calendar for Atibaia

In seasonPeak

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

Atibaia's rainy season runs October–March, 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 Atibaia?

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

7.1
Sightseeing
5th-best month of the year
6.5
Beach & pool
2nd-best month of the year

September is one of the better times to visit Atibaia for general sightseeing. The water and warmth also suit a beach or pool day.

What to pack for Atibaia in September

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

In September, Atibaia sees daytime highs around 25°C and nights near 15°C. Worth packing: light clothes, rain gear and sun protection. About 9 days see rain.

light clothesrain gearsun protection

UV index in Atibaia in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 8 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Atibaia peaks around January 20 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 20UV 15Jul 12UV 6
UV index (midday)Level
Jan15Extreme
Feb15Extreme
Mar12Extreme
Apr9Very high
May7High
Jun6High
Jul5High
Aug8Very high
Sep8Very high
Oct11Extreme
Nov13Extreme
Dec14Extreme

Air quality in Atibaia 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 Atibaia is worst in June — around 71 µg/m³ PM2.5 (unhealthy), about 2.3× the cleanest month (December, 31 µg/m³).

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

020406080JanFebMarAprMayJunJulAugSepOctNovDecModeratePoorUnhealthyPoorModerateJun 2370 µg/m³Dec 2031 µg/m³
PM2.5 (µg/m³)Level
Jan32Moderate
Feb34Moderate
Mar41Poor
Apr48Poor
May62Unhealthy
Jun71Unhealthy
Jul70Unhealthy
Aug60Unhealthy
Sep53Poor
Oct39Poor
Nov32Moderate
Dec31Moderate
Location & terrain

Where is Atibaia?

Atibaia sits at 23.1°S, 46.6°W, 817 m above sea level, in Brazil. The nearest listed city is Bom Jesus dos Perdões, 9.0 km away.

Topography around Atibaia

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

Within 3 km, the terrain around Atibaia has only modest variations in elevation — a maximum elevation change of 147 m around an average of 780 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 679 m; within 80 km, very significant variations in elevation — a maximum elevation change of 2,000 m.

The land around Atibaia is covered by artificial surfaces (44%), trees (32%) and grassland (21%) within 3 km, trees (52%) and grassland (34%) within 16 km, and trees (48%) and grassland (30%) within 80 km.

3 km
147 m
16 km
679 m
80 km
2,000 m
treesgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Bom Jesus dos Perdões 9.0 km · Nazaré Paulista 17 km · Bragança Paulista 18 km · Jarinu 18 km · Piracaia 21 km · Mairiporã 23 km · Campo Limpo Paulista 26 km · Francisco Morato 27 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 Atibaia (-23.1169°, -46.5503°, elevation 817 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).