Oeiras weather in September

In September, Oeiras sees average daytime highs of 36°C and overnight lows near 25°C, with 1 mm of rain across 0.2 wet days and about 12 hours of daylight. It is the 2nd-warmest and 11th-wettest month of the year here.

Day-to-day highs hold fairly steady near 36°C through the month. The sky is clear or mostly clear about 79% of the time in September, and the air most often feels comfortable.

Daylight stretches from about 11 h 54 min at the start of September to 12 h 06 min by month's end. Set against the rest of the year, September is Oeiras's 2nd-clearest and 4th-windiest month. For the whole year in context, see Oeiras's year-round climate.

Daytime high: 36°; 2nd warmest
Overnight low: 25°; 10th coldest
Rainfall: 1 mm; 0.2 wet days
Daylight: 12 hours; 5:44 AM – 5:42 PM
Cloud cover: 26%; 2nd clearest
Wind: 14 km/h; 4th windiest
Solar energy: 6.77 kWh/m²
Travel score: 2.4; out of 10

Oeiras is human settlement in Brazil.

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

← August Oeiras 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 36°C through the month.

A typical September day in Oeiras reaches about 36°C in the afternoon and slips back to 25°C overnight — a 11°C spread between the day's warmth and the night's chill. On most days the high lands between 35°C and 38°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)	36	36	36	36	36	36	36	36	36	36	36	36	36	36	36	36	37	37	37	37	37	37	37	37	37	37	37	37	37	37
Avg low (°C)	24	24	24	24	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25	26	26	26	26	26	26	26	26	26

	Avg high (°C)	Avg low (°C)
1	36	24
2	36	24
3	36	24
4	36	24
5	36	25
6	36	25
7	36	25
8	36	25
9	36	25
10	36	25
11	36	25
12	36	25
13	36	25
14	36	25
15	36	25
16	36	25
17	37	25
18	37	25
19	37	25
20	37	25
21	37	25
22	37	26
23	37	26
24	37	26
25	37	26
26	37	26
27	37	26
28	37	26
29	37	26
30	37	26

How September really feels in Oeiras

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.

Oeiras weather by month

How September compares with the rest of the year at a glance. September is the 2nd-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	32° / 24°	165	19.7	12.4	3.0
Feb	32° / 23°	166	18.2	12.2	3.1
Mar	32° / 23°	161	20.5	12	3.2
Apr	32° / 24°	90	13.2	11.8	3.6
May	33° / 24°	33	4.8	11.7	3.8
Jun	33° / 24°	3	0.5	11.6	4.2
Jul	34° / 23°	2	0.4	11.6	4.1
Aug	35° / 24°	0	0.1	11.8	3.4
Sep	36° / 25°	1	0.2	12	2.4
Oct	37° / 27°	14	2	12.2	2.0
Nov	35° / 26°	44	6.2	12.3	2.5
Dec	34° / 25°	81	10.7	12.4	2.9

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 79% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 11% of September, with mostly cloudy or overcast conditions the remaining 10%. Skies tend to cloud over 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 (%)	90	90	90	90	90	90	91	91	91	90	90	91	91	91	91	91	91	91	91	91	91	91	90	89	89	89	88	88	87	86
Cloudier (%)	10	10	10	10	10	10	9	9	9	10	10	9	9	9	9	9	9	9	9	9	9	9	10	11	11	11	12	12	13	14

	Clearer (%)	Cloudier (%)
1	90	10
2	90	10
3	90	10
4	90	10
5	90	10
6	90	10
7	91	9
8	91	9
9	91	9
10	90	10
11	90	10
12	91	9
13	91	9
14	91	9
15	91	9
16	91	9
17	91	9
18	91	9
19	91	9
20	91	9
21	91	9
22	91	9
23	90	10
24	89	11
25	89	11
26	89	11
27	88	12
28	88	12
29	87	13
30	86	14

Chance of precipitation in September

Any precipitation

Oeiras gets around 1 mm of rain over 0.2 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 1% and peaks near 2% 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 (%)	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	1	1	1	1	1	1	1	1	1	1	1	1	2	2	2

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

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 56% of days. It rarely turns muggy — the humid and sticky bands barely register.

	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
Dry (%)	9	9	9	9	9	9	9	9	9	9	9	9	9	9	8	8	8	8	7	7	7	6	6	6	6	6	6	5	5	6
Comfortable (%)	61	60	60	59	59	58	57	57	56	56	56	55	55	54	55	56	55	55	56	55	55	56	56	55	54	54	53	54	53	52
Humid (%)	28	29	29	30	30	30	31	31	32	32	32	33	33	33	33	32	32	32	32	32	32	32	32	32	33	33	33	33	33	33
Muggy (%)	2	2	2	2	2	3	3	3	3	3	3	3	3	4	4	4	5	5	5	6	6	6	6	7	7	7	8	8	9	9

	Dry (%)	Comfortable (%)	Humid (%)	Muggy (%)
1	9	61	28	2
2	9	60	29	2
3	9	60	29	2
4	9	59	30	2
5	9	59	30	2
6	9	58	30	3
7	9	57	31	3
8	9	57	31	3
9	9	56	32	3
10	9	56	32	3
11	9	56	32	3
12	9	55	33	3
13	9	55	33	3
14	9	54	33	4
15	8	55	33	4
16	8	56	32	4
17	8	55	32	5
18	8	55	32	5
19	7	56	32	5
20	7	55	32	6
21	7	55	32	6
22	6	56	32	6
23	6	56	32	6
24	6	55	32	7
25	6	54	33	7
26	6	54	33	7
27	6	53	33	8
28	5	54	33	8
29	5	53	33	9
30	6	52	33	9

Wind in September

Winds average 14 km/h in September.

Across September, daily wind ranges from about 12 km/h on the calmest days to 15 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)	15	15	15	15	15	15	15	15	15	15	14	14	14	14	14	14	14	14	13	13	13	13	13	13	12	12	12	12	12	12
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	calm

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

Sunrise & sunset in September

DaylightNight

Daylight runs from about 11 h 54 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 12 minutes over September. Sunrise moves from 5:52 AM to 5:36 AM, and sunset from 5:44 PM to 5:39 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	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	12.1
Sunrise (AM)	5:52	5:52	5:51	5:51	5:50	5:50	5:49	5:49	5:48	5:47	5:47	5:46	5:46	5:45	5:45	5:44	5:43	5:43	5:42	5:42	5:41	5:41	5:40	5:39	5:39	5:38	5:38	5:37	5:37	5:36
Sunset (PM)	5:44	5:44	5:44	5:44	5:44	5:43	5:43	5:43	5:43	5:43	5:43	5:42	5:42	5:42	5:42	5:42	5:42	5:41	5:41	5:41	5:41	5:41	5:41	5:40	5:40	5:40	5:40	5:40	5:40	5:39

	Daylight (h)	Sunrise (AM)	Sunset (PM)
1	11.9	5:52	5:44
2	11.9	5:52	5:44
3	11.9	5:51	5:44
4	11.9	5:51	5:44
5	11.9	5:50	5:44
6	11.9	5:50	5:43
7	11.9	5:49	5:43
8	11.9	5:49	5:43
9	11.9	5:48	5:43
10	11.9	5:47	5:43
11	11.9	5:47	5:43
12	11.9	5:46	5:42
13	11.9	5:46	5:42
14	11.9	5:45	5:42
15	12.0	5:45	5:42
16	12.0	5:44	5:42
17	12.0	5:43	5:42
18	12.0	5:43	5:41
19	12.0	5:42	5:41
20	12.0	5:42	5:41
21	12.0	5:41	5:41
22	12.0	5:41	5:41
23	12.0	5:40	5:41
24	12.0	5:39	5:40
25	12.0	5:39	5:40
26	12.0	5:38	5:40
27	12.0	5:38	5:40
28	12.0	5:37	5:40
29	12.0	5:37	5:40
30	12.1	5:36	5:39

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 6.77 kWh/m² — the sunniest month for solar.

For context, solar energy here swings from a low near 4.96 kWh/m² to a high of 6.77 kWh/m² in September across the year — September's 6.77 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)	6.6	6.6	6.6	6.6	6.7	6.7	6.7	6.7	6.7	6.7	6.8	6.8	6.8	6.8	6.8	6.8	6.8	6.8	6.8	6.8	6.8	6.8	6.8	6.8	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	6.6	Intense
2	6.6	Intense
3	6.6	Intense
4	6.6	Intense
5	6.7	Intense
6	6.7	Intense
7	6.7	Intense
8	6.7	Intense
9	6.7	Intense
10	6.7	Intense
11	6.8	Intense
12	6.8	Intense
13	6.8	Intense
14	6.8	Intense
15	6.8	Intense
16	6.8	Intense
17	6.8	Intense
18	6.8	Intense
19	6.8	Intense
20	6.8	Intense
21	6.8	Intense
22	6.8	Intense
23	6.8	Intense
24	6.8	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

Hazard calendar for Oeiras

In seasonPeak

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

Oeiras's rainy season runs December–April, 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 Oeiras?

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

2.4

Sightseeing

11th-best month of the year

6.0

Beach & pool

5th-best month of the year

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

What to pack for Oeiras in September

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

In September, Oeiras sees daytime highs around 36°C and nights near 25°C. Pack light clothes and sun protection.

light clothessun protection

UV index in Oeiras 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 Oeiras peaks around March 10 at about 15 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near June 23 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)	14	15	15	13	11	10	10	10	12	12	12	12
Level	Extreme	Extreme	Extreme	Extreme	Extreme	Very high	Very high	Very high	Extreme	Extreme	Extreme	Extreme

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

Location & terrain

Where is Oeiras?

Oeiras sits at 7.0°S, 42.1°W, 181 m above sea level, in Brazil. The nearest listed city is Picos, 74 km away.

Topography around Oeiras

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

Within 3 km, the terrain around Oeiras has only modest variations in elevation — a maximum elevation change of 114 m around an average of 196 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 173 m; within 80 km, significant variations in elevation — a maximum elevation change of 468 m.

The land around Oeiras is covered by shrubs (53%) within 3 km, shrubs (68%) and trees (24%) within 16 km, and shrubs (56%) and trees (33%) within 80 km.

3 km

114 m

shrubs 53%

16 km

173 m

shrubs 68%

80 km

468 m

shrubs 56%

treesshrubsgrasslandcroplandartificial surfaces

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

September weather nearby: Picos 74 km · Valença do Piauí 81 km · Floriano 103 km · Barão de Grajaú 103 km · Regeneração 108 km · Jaicós 116 km · Amarante 117 km · Água Branca 138 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 Oeiras (-7.0253°, -42.1311°, elevation 181 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	36	24
2	36	24
3	36	24
4	36	24
5	36	25
6	36	25
7	36	25
8	36	25
9	36	25
10	36	25
11	36	25
12	36	25
13	36	25
14	36	25
15	36	25
16	36	25
17	37	25
18	37	25
19	37	25
20	37	25
21	37	25
22	37	26
23	37	26
24	37	26
25	37	26
26	37	26
27	37	26
28	37	26
29	37	26
30	37	26

	Clearer (%)	Cloudier (%)
1	90	10
2	90	10
3	90	10
4	90	10
5	90	10
6	90	10
7	91	9
8	91	9
9	91	9
10	90	10
11	90	10
12	91	9
13	91	9
14	91	9
15	91	9
16	91	9
17	91	9
18	91	9
19	91	9
20	91	9
21	91	9
22	91	9
23	90	10
24	89	11
25	89	11
26	89	11
27	88	12
28	88	12
29	87	13
30	86	14

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

	Dry (%)	Comfortable (%)	Humid (%)	Muggy (%)
1	9	61	28	2
2	9	60	29	2
3	9	60	29	2
4	9	59	30	2
5	9	59	30	2
6	9	58	30	3
7	9	57	31	3
8	9	57	31	3
9	9	56	32	3
10	9	56	32	3
11	9	56	32	3
12	9	55	33	3
13	9	55	33	3
14	9	54	33	4
15	8	55	33	4
16	8	56	32	4
17	8	55	32	5
18	8	55	32	5
19	7	56	32	5
20	7	55	32	6
21	7	55	32	6
22	6	56	32	6
23	6	56	32	6
24	6	55	32	7
25	6	54	33	7
26	6	54	33	7
27	6	53	33	8
28	5	54	33	8
29	5	53	33	9
30	6	52	33	9

	Avg high (°C)	Avg low (°C)
1	36	24
2	36	24
3	36	24
4	36	24
5	36	25
6	36	25
7	36	25
8	36	25
9	36	25
10	36	25
11	36	25
12	36	25
13	36	25
14	36	25
15	36	25
16	36	25
17	37	25
18	37	25
19	37	25
20	37	25
21	37	25
22	37	26
23	37	26
24	37	26
25	37	26
26	37	26
27	37	26
28	37	26
29	37	26
30	37	26

	Clearer (%)	Cloudier (%)
1	90	10
2	90	10
3	90	10
4	90	10
5	90	10
6	90	10
7	91	9
8	91	9
9	91	9
10	90	10
11	90	10
12	91	9
13	91	9
14	91	9
15	91	9
16	91	9
17	91	9
18	91	9
19	91	9
20	91	9
21	91	9
22	91	9
23	90	10
24	89	11
25	89	11
26	89	11
27	88	12
28	88	12
29	87	13
30	86	14

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

	Dry (%)	Comfortable (%)	Humid (%)	Muggy (%)
1	9	61	28	2
2	9	60	29	2
3	9	60	29	2
4	9	59	30	2
5	9	59	30	2
6	9	58	30	3
7	9	57	31	3
8	9	57	31	3
9	9	56	32	3
10	9	56	32	3
11	9	56	32	3
12	9	55	33	3
13	9	55	33	3
14	9	54	33	4
15	8	55	33	4
16	8	56	32	4
17	8	55	32	5
18	8	55	32	5
19	7	56	32	5
20	7	55	32	6
21	7	55	32	6
22	6	56	32	6
23	6	56	32	6
24	6	55	32	7
25	6	54	33	7
26	6	54	33	7
27	6	53	33	8
28	5	54	33	8
29	5	53	33	9
30	6	52	33	9

	Avg high (°C)	Avg low (°C)
1	36	24
2	36	24
3	36	24
4	36	24
5	36	25
6	36	25
7	36	25
8	36	25
9	36	25
10	36	25
11	36	25
12	36	25
13	36	25
14	36	25
15	36	25
16	36	25
17	37	25
18	37	25
19	37	25
20	37	25
21	37	25
22	37	26
23	37	26
24	37	26
25	37	26
26	37	26
27	37	26
28	37	26
29	37	26
30	37	26

	Clearer (%)	Cloudier (%)
1	90	10
2	90	10
3	90	10
4	90	10
5	90	10
6	90	10
7	91	9
8	91	9
9	91	9
10	90	10
11	90	10
12	91	9
13	91	9
14	91	9
15	91	9
16	91	9
17	91	9
18	91	9
19	91	9
20	91	9
21	91	9
22	91	9
23	90	10
24	89	11
25	89	11
26	89	11
27	88	12
28	88	12
29	87	13
30	86	14

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

	Dry (%)	Comfortable (%)	Humid (%)	Muggy (%)
1	9	61	28	2
2	9	60	29	2
3	9	60	29	2
4	9	59	30	2
5	9	59	30	2
6	9	58	30	3
7	9	57	31	3
8	9	57	31	3
9	9	56	32	3
10	9	56	32	3
11	9	56	32	3
12	9	55	33	3
13	9	55	33	3
14	9	54	33	4
15	8	55	33	4
16	8	56	32	4
17	8	55	32	5
18	8	55	32	5
19	7	56	32	5
20	7	55	32	6
21	7	55	32	6
22	6	56	32	6
23	6	56	32	6
24	6	55	32	7
25	6	54	33	7
26	6	54	33	7
27	6	53	33	8
28	5	54	33	8
29	5	53	33	9
30	6	52	33	9