Santa Helena weather in September

In September, Santa Helena sees average daytime highs of 27°C and overnight lows near 17°C, with 133 mm of rain across 9.2 wet days and about 11.8 hours of daylight. It is the 8th-warmest and 4th-wettest month of the year here.

Day-to-day highs hold fairly steady near 27°C through the month. The sky is clear or mostly clear about 48% 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 Santa Helena's 3rd-clearest and 2nd-windiest month. For the whole year in context, see Santa Helena's year-round climate.

Daytime high
27°
8th warmest
Overnight low
17°
5th coldest
Rainfall
133 mm
9.2 wet days
Daylight
11 h 54 min
7:36 AM – 7:27 PM
Cloud cover
47%
3rd clearest
Wind
12 km/h
2nd windiest
Solar energy
4.91 kWh/m²
Travel score
6.8
out of 10

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 27°C through the month.

A typical September day in Santa Helena reaches about 27°C in the afternoon and slips back to 17°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 34°C. Set against its neighbours, September runs about 2°C warmer than August and about 2°C cooler than October.

10°15°20°25°30°35°151015202530
Avg high (°C)Avg low (°C)
12716
22717
32717
42717
52717
62717
72717
82717
92717
102717
112717
122717
132717
142717
152717
162717
172717
182717
192717
202717
212717
222718
232718
242718
252718
262718
272718
282818
292818
302818

How September really feels in Santa Helena

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.

Santa Helena weather by month

How September compares with the rest of the year at a glance. September is the 8th-warmest and 4th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan31° / 23°12815.213.43.9
Feb31° / 23°12513.812.94.0
Mar30° / 22°1011212.24.7
Apr28° / 19°1068.411.46.3
May24° / 16°1399.110.87.1
Jun23° / 15°1148.810.57.1
Jul23° / 14°997.910.67.4
Aug25° / 15°856.511.17.7
Sep27° / 17°1339.211.86.8
Oct29° / 20°16212.612.65.3
Nov30° / 21°13311.613.24.9
Dec31° / 22°15414.413.54.2

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 48% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 12% of September, with mostly cloudy or overcast conditions the remaining 40%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
16832
26832
36634
46634
56634
66436
76436
86337
96337
106337
116238
126238
136337
146238
156238
166139
176139
186040
196040
205842
215743
225644
235644
245446
255347
265248
275050
284951
294852
304753

Chance of precipitation in September

Any precipitation

Santa Helena gets around 133 mm of rain over 9.2 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 30% 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 (%)
122
222
323
424
524
625
726
826
927
1027
1127
1228
1328
1429
1529
1630
1730
1831
1932
2032
2133
2234
2335
2436
2537
2638
2738
2839
2939
3040

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 33% of days. Sticky, muggy-or-worse air turns up on roughly 16% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
130363050
229353050
328353160
428353160
527353160
627343270
727343280
826333280
926323390
10253233100
11253134100
12253034110
13242935120
14242835130
15232835140
16232735150
17232734160
18232634170
19222534180
20222534200
21212533210
22212433220
23202433230
24192333250
25182333260
26172333270
27162232291
28152232301
29142232311
30132133321

Wind in September

Winds average 12 km/h in September.

Across September, daily wind ranges from about 12 km/h on the calmest days to 12 km/h at its breeziest. It stays fairly steady from day to day.

051015151015202530
Wind speed (km/h)Feels
112light breeze
212light breeze
312light breeze
412light breeze
512light breeze
612light breeze
712light breeze
812light breeze
912light breeze
1012light breeze
1112light breeze
1212light breeze
1312calm
1412calm
1512calm
1612calm
1712calm
1812calm
1912calm
2012calm
2112calm
2212calm
2312calm
2412calm
2512calm
2612calm
2712calm
2812calm
2912calm
3012calm

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 7:52 AM to 7:20 AM, and sunset from 7:22 PM to 7:33 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
111.57:527:22
211.57:517:22
311.57:507:23
411.67:497:23
511.67:487:23
611.67:477:24
711.67:467:24
811.77:457:24
911.77:447:25
1011.77:437:25
1111.77:427:26
1211.87:407:26
1311.87:397:26
1411.87:387:27
1511.87:377:27
1611.97:367:27
1711.97:357:28
1811.97:347:28
1911.97:337:28
2012.07:317:29
2112.07:307:29
2212.07:297:30
2312.07:287:30
2412.17:277:30
2512.17:267:31
2612.17:257:31
2712.17:247:32
2812.27:237:32
2912.27:227:32
3012.27:207:33

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.91 kWh/m².

For context, solar energy here swings from a low near 2.97 kWh/m² to a high of 6.39 kWh/m² in December across the year — September's 4.91 kWh/m² falls in the middle.

0246151015202530
Solar energy (kWh/m²)Level
14.7Bright
24.8Bright
34.8Bright
44.8Bright
54.8Bright
64.8Bright
74.8Bright
84.8Bright
94.9Bright
104.9Bright
114.9Bright
124.9Bright
134.9Bright
144.9Bright
154.9Bright
165.0Bright
175.0Bright
185.0Bright
195.0Bright
205.0Bright
215.0Bright
225.0Bright
235.0Bright
245.0Bright
255.0Bright
265.0Bright
275.0Bright
285.0Bright
295.0Bright
305.0Bright
Planning a trip in September

Is September a good time to visit Santa Helena?

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
7.0
Beach & pool
3rd-best month of the year

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

What to pack for Santa Helena in September

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

In September, Santa Helena sees daytime highs around 27°C and nights near 17°C. Pack light clothes. Worth having: rain gear and sun protection. About 9 days see rain.

light clothesrain gearsun protection

UV index in Santa Helena in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 6 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Santa Helena peaks around January 19 at about 15 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near July 11 at about 5 (high).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeVery highHighExtremeJan 19UV 15Jul 11UV 5
UV index (midday)Level
Jan15Extreme
Feb14Extreme
Mar12Extreme
Apr9Very high
May6High
Jun5High
Jul5Moderate
Aug7High
Sep6High
Oct10Very high
Nov12Extreme
Dec13Extreme

Air quality in Santa Helena 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 Santa Helena is worst in September — around 21 µg/m³ PM2.5 (moderate), about 3.6× the cleanest month (March, 6 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodSep 1620 µg/m³Mar 156 µg/m³
PM2.5 (µg/m³)Level
Jan7Good
Feb6Good
Mar6Good
Apr7Good
May7Good
Jun8Good
Jul7Good
Aug12Moderate
Sep21Moderate
Oct12Good
Nov8Good
Dec7Good
Location & terrain

Where is Santa Helena?

Santa Helena sits at 24.9°S, 54.3°W, 254 m above sea level, in Brazil. The nearest listed city is Marechal Cândido Rondon, 44 km away.

Topography around Santa Helena

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

Within 3 km, the terrain around Santa Helena has only modest variations in elevation — a maximum elevation change of 72 m around an average of 238 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 259 m; within 80 km, large variations in elevation — a maximum elevation change of 674 m.

The land around Santa Helena is covered by cropland (31%), trees (30%) and water (20%) within 3 km, trees (33%), cropland (31%) and water (28%) within 16 km, and cropland (57%) and trees (28%) within 80 km.

3 km
72 m
16 km
259 m
80 km
674 m
treesgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Marechal Cândido Rondon 44 km · Medianeira 54 km · Matelândia 55 km · São Miguel do Iguaçu 55 km · Toledo 62 km · Santa Terezinha de Itaipu 65 km · Ciudad del Este 78 km · Foz do Iguacu 81 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 Santa Helena (-24.8603°, -54.3328°, elevation 254 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).