Açu weather in September

In September, Açu sees average daytime highs of 35°C and overnight lows near 23°C, with 1 mm of rain across 0.1 wet days and about 12 hours of daylight. It is the 4th-warmest and 12th-wettest month of the year here.

Day-to-day highs hold fairly steady near 35°C through the month. The sky is clear or mostly clear about 73% of the time in September, and the air most often feels humid.

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

Daytime high: 35°; 4th warmest
Overnight low: 23°; 3rd coldest
Rainfall: 1 mm; 0.1 wet days
Daylight: 12 hours; 5:23 AM – 5:21 PM
Cloud cover: 29%; 1st clearest
Wind: 19 km/h; 1st windiest
Solar energy: 6.49 kWh/m²
Travel score: 3.1; out of 10

Açu is human settlement in Brazil.

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

← August Açu 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 35°C through the month.

A typical September day in Açu reaches about 35°C in the afternoon and slips back to 23°C overnight — a 13°C spread between the day's warmth and the night's chill. On most days the high lands between 34°C and 37°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)	35	35	35	35	35	35	35	35	35	35	35	35	35	35	35	35	35	35	35	35	35	36	36	36	36	36	36	36	36	36
Avg low (°C)	22	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	35	22
2	35	23
3	35	23
4	35	23
5	35	23
6	35	23
7	35	23
8	35	23
9	35	23
10	35	23
11	35	23
12	35	23
13	35	23
14	35	23
15	35	23
16	35	23
17	35	23
18	35	23
19	35	23
20	35	23
21	35	23
22	36	23
23	36	23
24	36	23
25	36	23
26	36	23
27	36	23
28	36	23
29	36	23
30	36	23

How September really feels in Açu

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.

Açu weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 12th-wettest month here — the current month is highlighted below.

Month	High / Low (°C)	Rainfall (mm)	Wet days	Daylight (hours)	Travel score
Jan	35° / 24°	50	8.7	12.3	2.7
Feb	34° / 24°	63	10.5	12.2	2.8
Mar	33° / 24°	92	14.8	12	2.9
Apr	33° / 24°	86	13.3	11.9	3.2
May	33° / 24°	40	6.7	11.7	3.6
Jun	33° / 23°	24	4.3	11.7	4.1
Jul	33° / 22°	15	2.4	11.7	4.2
Aug	34° / 22°	3	0.4	11.8	3.7
Sep	35° / 23°	1	0.1	12	3.1
Oct	36° / 23°	1	0.1	12.1	2.7
Nov	36° / 24°	2	0.4	12.3	2.7
Dec	36° / 24°	10	2.5	12.3	2.6

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 73% of the time in September, the clearest month of the year.

Beyond those clear spells, partly cloudy skies cover about 18% of September, with mostly cloudy or overcast conditions the remaining 9%. Skies tend to open up as the month goes on.

	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 (%)	89	89	89	89	89	89	88	88	88	89	89	89	89	90	90	91	91	91	93	93	93	94	94	94	94	94	93	92	92	92
Cloudier (%)	11	11	11	11	11	11	12	12	12	11	11	11	11	10	10	9	9	9	7	7	7	6	6	6	6	6	7	8	8	8

	Clearer (%)	Cloudier (%)
1	89	11
2	89	11
3	89	11
4	89	11
5	89	11
6	89	11
7	88	12
8	88	12
9	88	12
10	89	11
11	89	11
12	89	11
13	89	11
14	90	10
15	90	10
16	91	9
17	91	9
18	91	9
19	93	7
20	93	7
21	93	7
22	94	6
23	94	6
24	94	6
25	94	6
26	94	6
27	93	7
28	92	8
29	92	8
30	92	8

Chance of precipitation in September

Any precipitation

Açu gets around 1 mm of rain over 0.1 wet days in September, the driest month. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 1% and peaks near 1% 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 (%)	1	1	1	1	1	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

	Rain chance (%)
1	1
2	1
3	1
4	1
5	1
6	1
7	1
8	1
9	1
10	1
11	1
12	1
13	1
14	1
15	1
16	1
17	1
18	1
19	0
20	0
21	0
22	0
23	0
24	0
25	0
26	0
27	0
28	0
29	0
30	0

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 59% of days. Sticky, muggy-or-worse air turns up on roughly 37% 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
Comfortable (%)	3	3	3	3	3	4	4	4	4	4	4	4	4	4	4	3	3	3	3	3	3	3	2	2	2	2	2	2	2	2
Humid (%)	65	65	65	65	65	64	64	63	63	62	62	61	60	60	59	59	58	58	57	57	56	56	57	57	57	56	56	56	54	54
Muggy (%)	32	32	32	32	32	32	32	33	33	34	34	35	36	36	37	38	39	39	40	40	41	41	41	41	41	42	42	42	43	43
Oppressive (%)	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	1	1

	Comfortable (%)	Humid (%)	Muggy (%)	Oppressive (%)
1	3	65	32	0
2	3	65	32	0
3	3	65	32	0
4	3	65	32	0
5	3	65	32	0
6	4	64	32	0
7	4	64	32	0
8	4	63	33	0
9	4	63	33	0
10	4	62	34	0
11	4	62	34	0
12	4	61	35	0
13	4	60	36	0
14	4	60	36	0
15	4	59	37	0
16	3	59	38	0
17	3	58	39	0
18	3	58	39	0
19	3	57	40	0
20	3	57	40	0
21	3	56	41	0
22	3	56	41	0
23	2	57	41	0
24	2	57	41	0
25	2	57	41	0
26	2	56	42	0
27	2	56	42	0
28	2	56	42	0
29	2	54	43	1
30	2	54	43	1

Wind in September

Winds average 19 km/h in September, the windiest month of the year.

Across September, daily wind ranges from about 18 km/h on the calmest days to 19 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)	18	19	19	19	19	19	19	19	19	19	19	19	19	19	19	19	19	19	19	19	19	19	19	19	19	19	19	19	19	19
Feels	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze

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

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 5:31 AM to 5:16 AM, and sunset from 5:24 PM to 5:18 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	11.9	11.9	11.9	11.9	11.9	11.9	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
Sunrise (AM)	5:31	5:30	5:30	5:29	5:29	5:28	5:28	5:27	5:27	5:26	5:26	5:25	5:24	5:24	5:23	5:23	5:22	5:22	5:21	5:21	5:20	5:20	5:19	5:19	5:18	5:18	5:17	5:17	5:16	5:16
Sunset (PM)	5:24	5:24	5:24	5:24	5:23	5:23	5:23	5:23	5:23	5:22	5:22	5:22	5:22	5:21	5:21	5:21	5:21	5:21	5:20	5:20	5:20	5:20	5:20	5:19	5:19	5:19	5:19	5:19	5:18	5:18

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

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 6.49 kWh/m².

For context, solar energy here swings from a low near 4.66 kWh/m² to a high of 6.8 kWh/m² in October across the year — September's 6.49 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)	6.1	6.1	6.2	6.2	6.2	6.2	6.2	6.3	6.3	6.3	6.3	6.4	6.4	6.4	6.4	6.5	6.5	6.5	6.6	6.6	6.6	6.7	6.7	6.7	6.8	6.8	6.8	6.8	6.8	6.8
Level	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense

	Solar energy (kWh/m²)	Level
1	6.1	Intense
2	6.1	Intense
3	6.2	Intense
4	6.2	Intense
5	6.2	Intense
6	6.2	Intense
7	6.2	Intense
8	6.3	Intense
9	6.3	Intense
10	6.3	Intense
11	6.3	Intense
12	6.4	Intense
13	6.4	Intense
14	6.4	Intense
15	6.4	Intense
16	6.5	Intense
17	6.5	Intense
18	6.5	Intense
19	6.6	Intense
20	6.6	Intense
21	6.6	Intense
22	6.7	Intense
23	6.7	Intense
24	6.7	Intense
25	6.8	Intense
26	6.8	Intense
27	6.8	Intense
28	6.8	Intense
29	6.8	Intense
30	6.8	Intense

Planning a trip in September

Is September a good time to visit Açu?

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

3.1

Sightseeing

6th-best month of the year

6.9

Beach & pool

4th-best month of the year

September is a weaker month for outdoor sightseeing in Açu. The water and warmth also suit a beach or pool day.

What to pack for Açu in September

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

In September, Açu sees daytime highs around 35°C and nights near 23°C. Pack light clothes and sun protection.

light clothessun protection

UV index in Açu 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 Açu peaks around March 15 at about 15 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near July 14 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)	13	14	15	14	11	10	10	10	12	12	12	12
Level	Extreme	Extreme	Extreme	Extreme	Extreme	Very high	Very high	Extreme	Extreme	Extreme	Extreme	Extreme

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

Location & terrain

Where is Açu?

Açu sits at 5.6°S, 36.9°W, 36 m above sea level, in Brazil. The nearest listed city is Jucurutu, 52 km away.

Topography around Açu

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

Within 3 km, the terrain around Açu has only modest variations in elevation — a maximum elevation change of 78 m around an average of 37 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 132 m; within 80 km, large variations in elevation — a maximum elevation change of 749 m.

The land around Açu is covered by grassland (35%) and artificial surfaces (22%) within 3 km, shrubs (49%) and grassland (35%) within 16 km, and shrubs (66%) and grassland (20%) within 80 km.

3 km

78 m

grassland 35%

16 km

132 m

shrubs 49%

80 km

749 m

shrubs 66%

treesshrubsgrasslandcroplandartificial surfacesbare terrainwaterwetland

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

September weather nearby: Jucurutu 52 km · Macau 60 km · Mossoró 65 km · Areia Branca 73 km · Lagoa Nova 75 km · Caraúbas 76 km · Guamaré 83 km · Currais Novos 87 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 Açu (-5.5767°, -36.9086°, elevation 36 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. 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	35	22
2	35	23
3	35	23
4	35	23
5	35	23
6	35	23
7	35	23
8	35	23
9	35	23
10	35	23
11	35	23
12	35	23
13	35	23
14	35	23
15	35	23
16	35	23
17	35	23
18	35	23
19	35	23
20	35	23
21	35	23
22	36	23
23	36	23
24	36	23
25	36	23
26	36	23
27	36	23
28	36	23
29	36	23
30	36	23

	Clearer (%)	Cloudier (%)
1	89	11
2	89	11
3	89	11
4	89	11
5	89	11
6	89	11
7	88	12
8	88	12
9	88	12
10	89	11
11	89	11
12	89	11
13	89	11
14	90	10
15	90	10
16	91	9
17	91	9
18	91	9
19	93	7
20	93	7
21	93	7
22	94	6
23	94	6
24	94	6
25	94	6
26	94	6
27	93	7
28	92	8
29	92	8
30	92	8

	Rain chance (%)
1	1
2	1
3	1
4	1
5	1
6	1
7	1
8	1
9	1
10	1
11	1
12	1
13	1
14	1
15	1
16	1
17	1
18	1
19	0
20	0
21	0
22	0
23	0
24	0
25	0
26	0
27	0
28	0
29	0
30	0

	Comfortable (%)	Humid (%)	Muggy (%)	Oppressive (%)
1	3	65	32	0
2	3	65	32	0
3	3	65	32	0
4	3	65	32	0
5	3	65	32	0
6	4	64	32	0
7	4	64	32	0
8	4	63	33	0
9	4	63	33	0
10	4	62	34	0
11	4	62	34	0
12	4	61	35	0
13	4	60	36	0
14	4	60	36	0
15	4	59	37	0
16	3	59	38	0
17	3	58	39	0
18	3	58	39	0
19	3	57	40	0
20	3	57	40	0
21	3	56	41	0
22	3	56	41	0
23	2	57	41	0
24	2	57	41	0
25	2	57	41	0
26	2	56	42	0
27	2	56	42	0
28	2	56	42	0
29	2	54	43	1
30	2	54	43	1

	Avg high (°C)	Avg low (°C)
1	35	22
2	35	23
3	35	23
4	35	23
5	35	23
6	35	23
7	35	23
8	35	23
9	35	23
10	35	23
11	35	23
12	35	23
13	35	23
14	35	23
15	35	23
16	35	23
17	35	23
18	35	23
19	35	23
20	35	23
21	35	23
22	36	23
23	36	23
24	36	23
25	36	23
26	36	23
27	36	23
28	36	23
29	36	23
30	36	23

	Clearer (%)	Cloudier (%)
1	89	11
2	89	11
3	89	11
4	89	11
5	89	11
6	89	11
7	88	12
8	88	12
9	88	12
10	89	11
11	89	11
12	89	11
13	89	11
14	90	10
15	90	10
16	91	9
17	91	9
18	91	9
19	93	7
20	93	7
21	93	7
22	94	6
23	94	6
24	94	6
25	94	6
26	94	6
27	93	7
28	92	8
29	92	8
30	92	8

	Rain chance (%)
1	1
2	1
3	1
4	1
5	1
6	1
7	1
8	1
9	1
10	1
11	1
12	1
13	1
14	1
15	1
16	1
17	1
18	1
19	0
20	0
21	0
22	0
23	0
24	0
25	0
26	0
27	0
28	0
29	0
30	0

	Comfortable (%)	Humid (%)	Muggy (%)	Oppressive (%)
1	3	65	32	0
2	3	65	32	0
3	3	65	32	0
4	3	65	32	0
5	3	65	32	0
6	4	64	32	0
7	4	64	32	0
8	4	63	33	0
9	4	63	33	0
10	4	62	34	0
11	4	62	34	0
12	4	61	35	0
13	4	60	36	0
14	4	60	36	0
15	4	59	37	0
16	3	59	38	0
17	3	58	39	0
18	3	58	39	0
19	3	57	40	0
20	3	57	40	0
21	3	56	41	0
22	3	56	41	0
23	2	57	41	0
24	2	57	41	0
25	2	57	41	0
26	2	56	42	0
27	2	56	42	0
28	2	56	42	0
29	2	54	43	1
30	2	54	43	1

	Avg high (°C)	Avg low (°C)
1	35	22
2	35	23
3	35	23
4	35	23
5	35	23
6	35	23
7	35	23
8	35	23
9	35	23
10	35	23
11	35	23
12	35	23
13	35	23
14	35	23
15	35	23
16	35	23
17	35	23
18	35	23
19	35	23
20	35	23
21	35	23
22	36	23
23	36	23
24	36	23
25	36	23
26	36	23
27	36	23
28	36	23
29	36	23
30	36	23

	Clearer (%)	Cloudier (%)
1	89	11
2	89	11
3	89	11
4	89	11
5	89	11
6	89	11
7	88	12
8	88	12
9	88	12
10	89	11
11	89	11
12	89	11
13	89	11
14	90	10
15	90	10
16	91	9
17	91	9
18	91	9
19	93	7
20	93	7
21	93	7
22	94	6
23	94	6
24	94	6
25	94	6
26	94	6
27	93	7
28	92	8
29	92	8
30	92	8

	Rain chance (%)
1	1
2	1
3	1
4	1
5	1
6	1
7	1
8	1
9	1
10	1
11	1
12	1
13	1
14	1
15	1
16	1
17	1
18	1
19	0
20	0
21	0
22	0
23	0
24	0
25	0
26	0
27	0
28	0
29	0
30	0

	Comfortable (%)	Humid (%)	Muggy (%)	Oppressive (%)
1	3	65	32	0
2	3	65	32	0
3	3	65	32	0
4	3	65	32	0
5	3	65	32	0
6	4	64	32	0
7	4	64	32	0
8	4	63	33	0
9	4	63	33	0
10	4	62	34	0
11	4	62	34	0
12	4	61	35	0
13	4	60	36	0
14	4	60	36	0
15	4	59	37	0
16	3	59	38	0
17	3	58	39	0
18	3	58	39	0
19	3	57	40	0
20	3	57	40	0
21	3	56	41	0
22	3	56	41	0
23	2	57	41	0
24	2	57	41	0
25	2	57	41	0
26	2	56	42	0
27	2	56	42	0
28	2	56	42	0
29	2	54	43	1
30	2	54	43	1