Tonantins weather in September

In September, Tonantins sees average daytime highs of 31°C and overnight lows near 23°C, with 148 mm of rain across 23.4 wet days and about 12 hours of daylight. It is the 1st-warmest and 11th-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 11% of the time in September, and the air most often feels miserable.

Daylight stretches from about 11 h 54 min at the start of September to 12 hours by month's end. Set against the rest of the year, September is Tonantins's 3rd-clearest and 8th-windiest month. For the whole year in context, see Tonantins's year-round climate.

Daytime high: 31°; 1st warmest
Overnight low: 23°; 4th coldest
Rainfall: 148 mm; 23.4 wet days
Daylight: 12 hours; 6:26 AM – 6:25 PM
Cloud cover: 71%; 3rd clearest
Wind: 4 km/h; 8th windiest
Solar energy: 5.15 kWh/m²
Travel score: 2.9; out of 10

Tonantins is human settlement in Brazil.

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

← August Tonantins year-round climate October →Best places to visit in September

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

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 Tonantins reaches about 31°C in the afternoon and slips back to 23°C overnight — a 8°C spread between the day's warmth and the night's chill. On most days the high lands between 29°C and 33°C. Set against its neighbours, September runs about 1°C warmer than August and on par with October.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Avg high (°C)	31	31	31	31	31	31	31	31	31	31	31	31	31	31	31	31	31	31	31	31	31	31	31	31	31	31	31	31	31	31
Avg low (°C)	23	23	23	23	23	23	23	23	23	23	23	23	23	23	23	23	23	23	23	23	23	23	23	23	23	23	23	23	23	23

	Avg high (°C)	Avg low (°C)
1	31	23
2	31	23
3	31	23
4	31	23
5	31	23
6	31	23
7	31	23
8	31	23
9	31	23
10	31	23
11	31	23
12	31	23
13	31	23
14	31	23
15	31	23
16	31	23
17	31	23
18	31	23
19	31	23
20	31	23
21	31	23
22	31	23
23	31	23
24	31	23
25	31	23
26	31	23
27	31	23
28	31	23
29	31	23
30	31	23

How September really feels in Tonantins

Once humidity and wind are folded in, September averages 30 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

heat index over the day's high

Days feeling ≤ 0°C

wind chill below the day's low

The story in September is heat — humidity pushes the afternoon "feels like" well above the raw temperature.

Tonantins weather by month

How September compares with the rest of the year at a glance. September is the 1st-warmest and 11th-wettest month here — the current month is highlighted below.

Month	High / Low (°C)	Rainfall (mm)	Wet days	Daylight (hours)	Travel score
Jan	30° / 23°	276	27.6	12.1	2.8
Feb	30° / 23°	269	25.3	12.1	2.7
Mar	30° / 23°	321	28.5	12	2.6
Apr	30° / 23°	328	28.3	11.9	2.7
May	29° / 23°	317	29.1	11.9	2.8
Jun	29° / 23°	215	26.3	11.8	3.2
Jul	30° / 22°	168	25.4	11.9	3.4
Aug	31° / 23°	136	22.9	11.9	3.3
Sep	31° / 23°	148	23.4	12	2.9
Oct	31° / 23°	185	25.4	12.1	2.7
Nov	31° / 23°	210	26	12.1	2.6
Dec	31° / 23°	258	28.9	12.2	2.6

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 11% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 20% of September, with mostly cloudy or overcast conditions the remaining 69%.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Clearer (%)	37	36	36	36	35	34	33	33	33	31	31	31	31	30	30	30	30	30	29	29	29	28	28	28	28	28	27	26	26	25
Cloudier (%)	63	64	64	64	65	66	67	67	67	69	69	69	69	70	70	70	70	70	71	71	71	72	72	72	72	72	73	74	74	75

	Clearer (%)	Cloudier (%)
1	37	63
2	36	64
3	36	64
4	36	64
5	35	65
6	34	66
7	33	67
8	33	67
9	33	67
10	31	69
11	31	69
12	31	69
13	31	69
14	30	70
15	30	70
16	30	70
17	30	70
18	30	70
19	29	71
20	29	71
21	29	71
22	28	72
23	28	72
24	28	72
25	28	72
26	28	72
27	27	73
28	26	74
29	26	74
30	25	75

Chance of precipitation in September

Any precipitation

Tonantins gets around 148 mm of rain over 23.4 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 78% and peaks near 79% on the wettest days.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Rain chance (%)	77	77	77	77	77	77	77	77	77	77	77	77	77	77	77	77	78	78	79	79	79	79	79	79	79	79	79	79	79	79

	Rain chance (%)
1	77
2	77
3	77
4	77
5	77
6	77
7	77
8	77
9	77
10	77
11	77
12	77
13	77
14	77
15	77
16	77
17	78
18	78
19	79
20	79
21	79
22	79
23	79
24	79
25	79
26	79
27	79
28	79
29	79
30	79

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, September lands in the miserable band about 55% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Muggy (%)	1	0	0	0	1	1	1	1	1	1	1	1	1	1	1	1	1	0	0	0	0	0	0	0	0	0	0	0	0	0
Oppressive (%)	53	54	53	53	51	51	50	50	50	49	48	47	47	46	45	44	43	42	42	41	41	40	40	39	38	38	37	37	36	36
Miserable (%)	46	46	47	47	48	48	49	49	50	50	51	52	52	53	54	55	56	58	58	59	59	60	60	61	62	62	63	63	64	64

	Muggy (%)	Oppressive (%)	Miserable (%)
1	1	53	46
2	0	54	46
3	0	53	47
4	0	53	47
5	1	51	48
6	1	51	48
7	1	50	49
8	1	50	49
9	1	50	50
10	1	49	50
11	1	48	51
12	1	47	52
13	1	47	52
14	1	46	53
15	1	45	54
16	1	44	55
17	1	43	56
18	0	42	58
19	0	42	58
20	0	41	59
21	0	41	59
22	0	40	60
23	0	40	60
24	0	39	61
25	0	38	62
26	0	38	62
27	0	37	63
28	0	37	63
29	0	36	64
30	0	36	64

Wind in September

Winds average 4 km/h in September.

Across September, daily wind ranges from about 4 km/h on the calmest days to 4 km/h at its breeziest. It stays fairly steady from day to day.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Wind speed (km/h)	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4
Feels	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm

	Wind speed (km/h)	Feels
1	4	calm
2	4	calm
3	4	calm
4	4	calm
5	4	calm
6	4	calm
7	4	calm
8	4	calm
9	4	calm
10	4	calm
11	4	calm
12	4	calm
13	4	calm
14	4	calm
15	4	calm
16	4	calm
17	4	calm
18	4	calm
19	4	calm
20	4	calm
21	4	calm
22	4	calm
23	4	calm
24	4	calm
25	4	calm
26	4	calm
27	4	calm
28	4	calm
29	4	calm
30	4	calm

Sunrise & sunset in September

DaylightNight

Daylight runs from about 11 h 54 min at the start of September to 12 hours by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 6 minutes over September. Sunrise moves from 6:33 AM to 6:20 AM, and sunset from 6:29 PM to 6:21 PM.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Daylight (h)	11.9	11.9	11.9	12.0	12.0	12.0	12.0	12.0	12.0	12.0	12.0	12.0	12.0	12.0	12.0	12.0	12.0	12.0	12.0	12.0	12.0	12.0	12.0	12.0	12.0	12.0	12.0	12.0	12.0	12.0
Sunrise (AM)	6:33	6:32	6:32	6:31	6:31	6:30	6:30	6:30	6:29	6:29	6:28	6:28	6:27	6:27	6:26	6:26	6:26	6:25	6:25	6:24	6:24	6:23	6:23	6:22	6:22	6:22	6:21	6:21	6:20	6:20
Sunset (PM)	6:29	6:29	6:29	6:28	6:28	6:28	6:28	6:27	6:27	6:27	6:27	6:26	6:26	6:26	6:25	6:25	6:25	6:24	6:24	6:24	6:24	6:23	6:23	6:23	6:22	6:22	6:22	6:22	6:21	6:21

	Daylight (h)	Sunrise (AM)	Sunset (PM)
1	11.9	6:33	6:29
2	11.9	6:32	6:29
3	11.9	6:32	6:29
4	12.0	6:31	6:28
5	12.0	6:31	6:28
6	12.0	6:30	6:28
7	12.0	6:30	6:28
8	12.0	6:30	6:27
9	12.0	6:29	6:27
10	12.0	6:29	6:27
11	12.0	6:28	6:27
12	12.0	6:28	6:26
13	12.0	6:27	6:26
14	12.0	6:27	6:26
15	12.0	6:26	6:25
16	12.0	6:26	6:25
17	12.0	6:26	6:25
18	12.0	6:25	6:24
19	12.0	6:25	6:24
20	12.0	6:24	6:24
21	12.0	6:24	6:24
22	12.0	6:23	6:23
23	12.0	6:23	6:23
24	12.0	6:22	6:23
25	12.0	6:22	6:22
26	12.0	6:22	6:22
27	12.0	6:21	6:22
28	12.0	6:21	6:22
29	12.0	6:20	6:21
30	12.0	6:20	6:21

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 5.15 kWh/m².

For context, solar energy here swings from a low near 3.67 kWh/m² to a high of 5.18 kWh/m² in October across the year — September's 5.15 kWh/m² sits near the top of that range.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Solar energy (kWh/m²)	5.0	5.0	5.0	5.0	5.0	5.1	5.1	5.1	5.1	5.1	5.1	5.1	5.1	5.2	5.2	5.2	5.2	5.2	5.2	5.2	5.2	5.2	5.2	5.2	5.2	5.2	5.2	5.2	5.2	5.2
Level	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright

	Solar energy (kWh/m²)	Level
1	5.0	Bright
2	5.0	Bright
3	5.0	Bright
4	5.0	Bright
5	5.0	Bright
6	5.1	Bright
7	5.1	Bright
8	5.1	Bright
9	5.1	Bright
10	5.1	Bright
11	5.1	Bright
12	5.1	Bright
13	5.1	Bright
14	5.2	Bright
15	5.2	Bright
16	5.2	Bright
17	5.2	Bright
18	5.2	Bright
19	5.2	Bright
20	5.2	Bright
21	5.2	Bright
22	5.2	Bright
23	5.2	Bright
24	5.2	Bright
25	5.2	Bright
26	5.2	Bright
27	5.2	Bright
28	5.2	Bright
29	5.2	Bright
30	5.2	Bright

Planning a trip in September

Is September a good time to visit Tonantins?

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

2.9

Sightseeing

4th-best month of the year

4.4

Beach & pool

3rd-best month of the year

September is a weaker month for outdoor sightseeing in Tonantins.

What to pack for Tonantins in September

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

In September, Tonantins sees daytime highs around 31°C and nights near 23°C. Pack light clothes and rain gear. Worth having: sun protection. About 23 days see rain.

light clothesrain gearsun protection

UV index in Tonantins in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 10 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Tonantins peaks around February 22 at about 15 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near August 16 at about 10 (very high).

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

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
UV index (midday)	15	15	15	14	13	11	10	10	10	12	13	12
Level	Extreme	Extreme	Extreme	Extreme	Extreme	Extreme	Very high	Very high	Very high	Extreme	Extreme	Extreme

	UV index (midday)	Level
Jan	15	Extreme
Feb	15	Extreme
Mar	15	Extreme
Apr	14	Extreme
May	13	Extreme
Jun	11	Extreme
Jul	10	Very high
Aug	10	Very high
Sep	10	Very high
Oct	12	Extreme
Nov	13	Extreme
Dec	12	Extreme

Air quality in Tonantins 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 Tonantins is worst in August — around 18 µg/m³ PM2.5 (moderate), about 1.8× the cleanest month (June, 10 µg/m³).

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

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
PM2.5 (µg/m³)	15	15	16	14	10	10	11	18	17	13	13	13
Level	Moderate	Moderate	Moderate	Moderate	Good	Good	Good	Moderate	Moderate	Moderate	Moderate	Moderate

	PM2.5 (µg/m³)	Level
Jan	15	Moderate
Feb	15	Moderate
Mar	16	Moderate
Apr	14	Moderate
May	10	Good
Jun	10	Good
Jul	11	Good
Aug	18	Moderate
Sep	17	Moderate
Oct	13	Moderate
Nov	13	Moderate
Dec	13	Moderate

Location & terrain

Where is Tonantins?

Tonantins sits at 2.9°S, 67.8°W, 55 m above sea level, in Brazil. The nearest listed city is Santo Antônio do Içá, 30 km away.

Topography around Tonantins

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

Within 3 km, the terrain around Tonantins has only modest variations in elevation — a maximum elevation change of 69 m around an average of 67 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 80 m; within 80 km, only modest variations in elevation — a maximum elevation change of 92 m.

The land around Tonantins is covered by trees (73%) within 3 km, trees (86%) within 16 km, and trees (95%) within 80 km.

3 km

69 m

trees 73%

16 km

80 m

trees 86%

80 km

92 m

trees 95%

treesgrasslandartificial surfaceswater

← August Tonantins year-round climate October →Best places to visit in September

September weather nearby: Santo Antônio do Içá 30 km · São Paulo de Olivença 131 km · Fonte Boa 194 km · Carauari 245 km · Maraã 272 km · Leticia 280 km · Tabatinga 281 km · Benjamin Constant 299 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

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 Tonantins (-2.8731°, -67.8022°, elevation 55 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).

	Avg high (°C)	Avg low (°C)
1	31	23
2	31	23
3	31	23
4	31	23
5	31	23
6	31	23
7	31	23
8	31	23
9	31	23
10	31	23
11	31	23
12	31	23
13	31	23
14	31	23
15	31	23
16	31	23
17	31	23
18	31	23
19	31	23
20	31	23
21	31	23
22	31	23
23	31	23
24	31	23
25	31	23
26	31	23
27	31	23
28	31	23
29	31	23
30	31	23

	Clearer (%)	Cloudier (%)
1	37	63
2	36	64
3	36	64
4	36	64
5	35	65
6	34	66
7	33	67
8	33	67
9	33	67
10	31	69
11	31	69
12	31	69
13	31	69
14	30	70
15	30	70
16	30	70
17	30	70
18	30	70
19	29	71
20	29	71
21	29	71
22	28	72
23	28	72
24	28	72
25	28	72
26	28	72
27	27	73
28	26	74
29	26	74
30	25	75

	Rain chance (%)
1	77
2	77
3	77
4	77
5	77
6	77
7	77
8	77
9	77
10	77
11	77
12	77
13	77
14	77
15	77
16	77
17	78
18	78
19	79
20	79
21	79
22	79
23	79
24	79
25	79
26	79
27	79
28	79
29	79
30	79

	Muggy (%)	Oppressive (%)	Miserable (%)
1	1	53	46
2	0	54	46
3	0	53	47
4	0	53	47
5	1	51	48
6	1	51	48
7	1	50	49
8	1	50	49
9	1	50	50
10	1	49	50
11	1	48	51
12	1	47	52
13	1	47	52
14	1	46	53
15	1	45	54
16	1	44	55
17	1	43	56
18	0	42	58
19	0	42	58
20	0	41	59
21	0	41	59
22	0	40	60
23	0	40	60
24	0	39	61
25	0	38	62
26	0	38	62
27	0	37	63
28	0	37	63
29	0	36	64
30	0	36	64

	Avg high (°C)	Avg low (°C)
1	31	23
2	31	23
3	31	23
4	31	23
5	31	23
6	31	23
7	31	23
8	31	23
9	31	23
10	31	23
11	31	23
12	31	23
13	31	23
14	31	23
15	31	23
16	31	23
17	31	23
18	31	23
19	31	23
20	31	23
21	31	23
22	31	23
23	31	23
24	31	23
25	31	23
26	31	23
27	31	23
28	31	23
29	31	23
30	31	23

	Clearer (%)	Cloudier (%)
1	37	63
2	36	64
3	36	64
4	36	64
5	35	65
6	34	66
7	33	67
8	33	67
9	33	67
10	31	69
11	31	69
12	31	69
13	31	69
14	30	70
15	30	70
16	30	70
17	30	70
18	30	70
19	29	71
20	29	71
21	29	71
22	28	72
23	28	72
24	28	72
25	28	72
26	28	72
27	27	73
28	26	74
29	26	74
30	25	75

	Rain chance (%)
1	77
2	77
3	77
4	77
5	77
6	77
7	77
8	77
9	77
10	77
11	77
12	77
13	77
14	77
15	77
16	77
17	78
18	78
19	79
20	79
21	79
22	79
23	79
24	79
25	79
26	79
27	79
28	79
29	79
30	79

	Muggy (%)	Oppressive (%)	Miserable (%)
1	1	53	46
2	0	54	46
3	0	53	47
4	0	53	47
5	1	51	48
6	1	51	48
7	1	50	49
8	1	50	49
9	1	50	50
10	1	49	50
11	1	48	51
12	1	47	52
13	1	47	52
14	1	46	53
15	1	45	54
16	1	44	55
17	1	43	56
18	0	42	58
19	0	42	58
20	0	41	59
21	0	41	59
22	0	40	60
23	0	40	60
24	0	39	61
25	0	38	62
26	0	38	62
27	0	37	63
28	0	37	63
29	0	36	64
30	0	36	64

	Avg high (°C)	Avg low (°C)
1	31	23
2	31	23
3	31	23
4	31	23
5	31	23
6	31	23
7	31	23
8	31	23
9	31	23
10	31	23
11	31	23
12	31	23
13	31	23
14	31	23
15	31	23
16	31	23
17	31	23
18	31	23
19	31	23
20	31	23
21	31	23
22	31	23
23	31	23
24	31	23
25	31	23
26	31	23
27	31	23
28	31	23
29	31	23
30	31	23

	Clearer (%)	Cloudier (%)
1	37	63
2	36	64
3	36	64
4	36	64
5	35	65
6	34	66
7	33	67
8	33	67
9	33	67
10	31	69
11	31	69
12	31	69
13	31	69
14	30	70
15	30	70
16	30	70
17	30	70
18	30	70
19	29	71
20	29	71
21	29	71
22	28	72
23	28	72
24	28	72
25	28	72
26	28	72
27	27	73
28	26	74
29	26	74
30	25	75

	Rain chance (%)
1	77
2	77
3	77
4	77
5	77
6	77
7	77
8	77
9	77
10	77
11	77
12	77
13	77
14	77
15	77
16	77
17	78
18	78
19	79
20	79
21	79
22	79
23	79
24	79
25	79
26	79
27	79
28	79
29	79
30	79

	Muggy (%)	Oppressive (%)	Miserable (%)
1	1	53	46
2	0	54	46
3	0	53	47
4	0	53	47
5	1	51	48
6	1	51	48
7	1	50	49
8	1	50	49
9	1	50	50
10	1	49	50
11	1	48	51
12	1	47	52
13	1	47	52
14	1	46	53
15	1	45	54
16	1	44	55
17	1	43	56
18	0	42	58
19	0	42	58
20	0	41	59
21	0	41	59
22	0	40	60
23	0	40	60
24	0	39	61
25	0	38	62
26	0	38	62
27	0	37	63
28	0	37	63
29	0	36	64
30	0	36	64