Belfast weather in September

In September, Belfast sees average daytime highs of 23°C and overnight lows near 9°C, with 22 mm of rain across 4.2 wet days and about 11.8 hours of daylight. It is the 7th-warmest and 8th-wettest month of the year here.

Highs climb over the month, from about 22°C in the first days to 23°C by the end. The sky is clear or mostly clear about 69% of the time in September, and the air most often feels dry.

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 Belfast's 5th-clearest and 1st-windiest month. For the whole year in context, see Belfast's year-round climate.

Daytime high: 23°; 7th warmest
Overnight low: 9°; 5th coldest
Rainfall: 22 mm; 4.2 wet days
Daylight: 11 h 54 min; 5:59 AM – 5:50 PM
Cloud cover: 29%; 5th clearest
Wind: 12 km/h; 1st windiest
Solar energy: 5.94 kWh/m²
Travel score: 8.2; out of 10

Belfast is town in South Africa.

Founded: 1890

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

← August Belfast 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

Highs climb over the month, from about 22°C in the first days to 23°C by the end.

A typical September day in Belfast reaches about 23°C in the afternoon and slips back to 9°C overnight — a 14°C spread between the day's warmth and the night's chill. On most days the high lands between 16°C and 27°C. Set against its neighbours, September runs about 3°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)	21	22	22	22	22	22	22	22	22	22	22	22	23	23	23	23	23	23	23	23	23	23	23	23	23	23	23	23	23	23
Avg low (°C)	7	7	7	8	8	8	8	8	8	8	8	8	9	9	9	9	9	9	9	9	9	9	9	10	10	10	10	10	10	10

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

How September really feels in Belfast

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

heat index over the day's high

Days feeling ≤ 0°C

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.

Belfast weather by month

How September compares with the rest of the year at a glance. September is the 7th-warmest and 8th-wettest month here — the current month is highlighted below.

Month	High / Low (°C)	Rainfall (mm)	Wet days	Daylight (hours)	Travel score
Jan	24° / 14°	140	17	13.4	5.9
Feb	24° / 14°	102	12.3	12.9	6.4
Mar	23° / 12°	97	11.8	12.2	6.7
Apr	21° / 10°	47	6.6	11.4	7.2
May	19° / 6°	14	2.5	10.8	7.8
Jun	17° / 3°	5	0.9	10.4	7.2
Jul	17° / 3°	6	0.8	10.6	7.2
Aug	19° / 5°	11	1.9	11.1	8.2
Sep	23° / 9°	22	4.2	11.8	8.2
Oct	23° / 11°	77	11.8	12.6	6.8
Nov	23° / 12°	122	15.6	13.3	5.9
Dec	24° / 13°	155	18.9	13.6	5.6

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 69% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 13% of September, with mostly cloudy or overcast conditions the remaining 18%. 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 (%)	85	86	86	85	85	86	85	85	84	84	84	84	82	82	82	82	82	82	82	81	81	81	81	80	80	80	78	78	77	76
Cloudier (%)	15	14	14	15	15	14	15	15	16	16	16	16	18	18	18	18	18	18	18	19	19	19	19	20	20	20	22	22	23	24

	Clearer (%)	Cloudier (%)
1	85	15
2	86	14
3	86	14
4	85	15
5	85	15
6	86	14
7	85	15
8	85	15
9	84	16
10	84	16
11	84	16
12	84	16
13	82	18
14	82	18
15	82	18
16	82	18
17	82	18
18	82	18
19	82	18
20	81	19
21	81	19
22	81	19
23	81	19
24	80	20
25	80	20
26	80	20
27	78	22
28	78	22
29	77	23
30	76	24

Chance of precipitation in September

Any precipitation

Belfast gets around 22 mm of rain over 4.2 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 14% and peaks near 27% on the wettest days. The odds climb toward the end of the month.

	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 (%)	9	9	9	10	10	10	10	11	11	11	11	11	11	11	12	12	12	13	14	15	16	17	18	19	21	22	23	24	25	27

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

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, September lands in the dry band about 100% 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 (%)	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100

	Dry (%)
1	100
2	100
3	100
4	100
5	100
6	100
7	100
8	100
9	100
10	100
11	100
12	100
13	100
14	100
15	100
16	100
17	100
18	100
19	100
20	100
21	100
22	100
23	100
24	100
25	100
26	100
27	100
28	100
29	100
30	100

Wind in September

Winds average 12 km/h in September, the windiest month of the year.

Across September, daily wind ranges from about 11 km/h on the calmest days to 12 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)	11	11	11	11	11	11	11	11	11	11	12	12	12	12	12	12	12	12	12	12	12	12	12	12	12	12	12	12	12	12
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	11	calm
2	11	calm
3	11	calm
4	11	calm
5	11	calm
6	11	calm
7	11	calm
8	11	calm
9	11	calm
10	11	calm
11	12	calm
12	12	calm
13	12	calm
14	12	calm
15	12	calm
16	12	calm
17	12	calm
18	12	calm
19	12	calm
20	12	calm
21	12	calm
22	12	calm
23	12	calm
24	12	calm
25	12	calm
26	12	calm
27	12	calm
28	12	calm
29	12	calm
30	12	calm

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 6:15 AM to 5:43 AM, and sunset from 5:44 PM to 5:56 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)	11.5	11.5	11.5	11.5	11.6	11.6	11.6	11.6	11.7	11.7	11.7	11.7	11.8	11.8	11.8	11.9	11.9	11.9	11.9	12.0	12.0	12.0	12.0	12.1	12.1	12.1	12.1	12.2	12.2	12.2
Sunrise (AM)	6:15	6:14	6:13	6:12	6:11	6:10	6:09	6:08	6:07	6:05	6:04	6:03	6:02	6:01	6:00	5:59	5:57	5:56	5:55	5:54	5:53	5:52	5:51	5:49	5:48	5:47	5:46	5:45	5:44	5:43
Sunset (PM)	5:44	5:44	5:44	5:45	5:45	5:46	5:46	5:47	5:47	5:47	5:48	5:48	5:49	5:49	5:49	5:50	5:50	5:51	5:51	5:51	5:52	5:52	5:53	5:53	5:53	5:54	5:54	5:55	5:55	5:56

	Daylight (h)	Sunrise (AM)	Sunset (PM)
1	11.5	6:15	5:44
2	11.5	6:14	5:44
3	11.5	6:13	5:44
4	11.5	6:12	5:45
5	11.6	6:11	5:45
6	11.6	6:10	5:46
7	11.6	6:09	5:46
8	11.6	6:08	5:47
9	11.7	6:07	5:47
10	11.7	6:05	5:47
11	11.7	6:04	5:48
12	11.7	6:03	5:48
13	11.8	6:02	5:49
14	11.8	6:01	5:49
15	11.8	6:00	5:49
16	11.9	5:59	5:50
17	11.9	5:57	5:50
18	11.9	5:56	5:51
19	11.9	5:55	5:51
20	12.0	5:54	5:51
21	12.0	5:53	5:52
22	12.0	5:52	5:52
23	12.0	5:51	5:53
24	12.1	5:49	5:53
25	12.1	5:48	5:53
26	12.1	5:47	5:54
27	12.1	5:46	5:54
28	12.2	5:45	5:55
29	12.2	5:44	5:55
30	12.2	5:43	5:56

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 5.94 kWh/m².

For context, solar energy here swings from a low near 3.98 kWh/m² to a high of 6.39 kWh/m² in December across the year — September's 5.94 kWh/m² falls in the middle.

	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)	5.5	5.6	5.6	5.7	5.7	5.7	5.7	5.8	5.8	5.8	5.8	5.9	5.9	5.9	5.9	6.0	6.0	6.0	6.0	6.0	6.1	6.1	6.1	6.1	6.1	6.2	6.2	6.2	6.2	6.2
Level	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense

	Solar energy (kWh/m²)	Level
1	5.5	Bright
2	5.6	Bright
3	5.6	Bright
4	5.7	Bright
5	5.7	Bright
6	5.7	Bright
7	5.7	Bright
8	5.8	Bright
9	5.8	Bright
10	5.8	Bright
11	5.8	Bright
12	5.9	Bright
13	5.9	Bright
14	5.9	Bright
15	5.9	Bright
16	6.0	Bright
17	6.0	Bright
18	6.0	Intense
19	6.0	Intense
20	6.0	Intense
21	6.1	Intense
22	6.1	Intense
23	6.1	Intense
24	6.1	Intense
25	6.1	Intense
26	6.2	Intense
27	6.2	Intense
28	6.2	Intense
29	6.2	Intense
30	6.2	Intense

Planning a trip in September

Hazard calendar for Belfast

In seasonPeak

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

Belfast'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 Belfast?

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

8.2

Sightseeing

1st-best month of the year

6.0

Beach & pool

1st-best month of the year

September is one of the better times to visit Belfast for general sightseeing.

What to pack for Belfast in September

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

In September, Belfast sees daytime highs around 23°C and nights near 9°C. Worth packing: light clothes and sun protection. About 4 days see rain.

light clothessun protection

UV index in Belfast 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 Belfast peaks around January 13 at about 14 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near June 20 at about 6 (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	14	13	8	7	6	6	8	10	11	12	14
Level	Extreme	Extreme	Extreme	Very high	High	High	High	Very high	Very high	Extreme	Extreme	Extreme

	UV index (midday)	Level
Jan	15	Extreme
Feb	14	Extreme
Mar	13	Extreme
Apr	8	Very high
May	7	High
Jun	6	High
Jul	6	High
Aug	8	Very high
Sep	10	Very high
Oct	11	Extreme
Nov	12	Extreme
Dec	14	Extreme

Air quality in Belfast 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 Belfast is worst in August — around 32 µg/m³ PM2.5 (moderate), about 3.8× the cleanest month (December, 9 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)	10	11	13	16	21	24	30	32	27	18	13	9
Level	Good	Good	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Good

	PM2.5 (µg/m³)	Level
Jan	10	Good
Feb	11	Good
Mar	13	Moderate
Apr	16	Moderate
May	21	Moderate
Jun	24	Moderate
Jul	30	Moderate
Aug	32	Moderate
Sep	27	Moderate
Oct	18	Moderate
Nov	13	Moderate
Dec	9	Good

Location & terrain

Where is Belfast?

Belfast sits at 25.7°S, 30.0°E, 1,873 m above sea level, in South Africa. The nearest listed city is Carolina, 43 km away.

Topography around Belfast

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

Within 3 km, the terrain around Belfast has only modest variations in elevation — a maximum elevation change of 97 m around an average of 1,882 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 440 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,596 m.

The land around Belfast is covered by grassland (58%) within 3 km, grassland (71%) within 16 km, and grassland (63%) within 80 km.

3 km

97 m

grassland 58%

16 km

440 m

grassland 71%

80 km

1,596 m

grassland 63%

treesshrubsgrasslandcroplandartificial surfacesbare terrainwater

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

September weather nearby: Carolina 43 km · Middelburg 58 km · Hendrina 61 km · Breyten 68 km · Lydenburg 78 km · Emalahleni 83 km · Nhlazatje 85 km · Lukwatini 89 km

South Africa travel facts

Travel advisory: Level 2; Exercise Increased Caution
Power plugs: Type C / M / N; 230 V · 50 Hz
Prices: ≈ 41% of US; price level, 2025
GDP per capita: $6,598; 2025
Happiness: 5.0 / 10; World Happiness, 2025
Safe drinking water: 68%; of population, 2024
Homicide rate: 43.7; per 100k, 2022
Road deaths: 22.2; per 100k/yr, 2019
Income group: Upper middle; World Bank
English: Very high; EF EPI 602
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 Belfast (-25.6899°, 30.035°, elevation 1,873 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	21	7
2	22	7
3	22	7
4	22	8
5	22	8
6	22	8
7	22	8
8	22	8
9	22	8
10	22	8
11	22	8
12	22	8
13	23	9
14	23	9
15	23	9
16	23	9
17	23	9
18	23	9
19	23	9
20	23	9
21	23	9
22	23	9
23	23	9
24	23	10
25	23	10
26	23	10
27	23	10
28	23	10
29	23	10
30	23	10

	Clearer (%)	Cloudier (%)
1	85	15
2	86	14
3	86	14
4	85	15
5	85	15
6	86	14
7	85	15
8	85	15
9	84	16
10	84	16
11	84	16
12	84	16
13	82	18
14	82	18
15	82	18
16	82	18
17	82	18
18	82	18
19	82	18
20	81	19
21	81	19
22	81	19
23	81	19
24	80	20
25	80	20
26	80	20
27	78	22
28	78	22
29	77	23
30	76	24

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

	Dry (%)
1	100
2	100
3	100
4	100
5	100
6	100
7	100
8	100
9	100
10	100
11	100
12	100
13	100
14	100
15	100
16	100
17	100
18	100
19	100
20	100
21	100
22	100
23	100
24	100
25	100
26	100
27	100
28	100
29	100
30	100

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

	Clearer (%)	Cloudier (%)
1	85	15
2	86	14
3	86	14
4	85	15
5	85	15
6	86	14
7	85	15
8	85	15
9	84	16
10	84	16
11	84	16
12	84	16
13	82	18
14	82	18
15	82	18
16	82	18
17	82	18
18	82	18
19	82	18
20	81	19
21	81	19
22	81	19
23	81	19
24	80	20
25	80	20
26	80	20
27	78	22
28	78	22
29	77	23
30	76	24

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

	Dry (%)
1	100
2	100
3	100
4	100
5	100
6	100
7	100
8	100
9	100
10	100
11	100
12	100
13	100
14	100
15	100
16	100
17	100
18	100
19	100
20	100
21	100
22	100
23	100
24	100
25	100
26	100
27	100
28	100
29	100
30	100

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

	Clearer (%)	Cloudier (%)
1	85	15
2	86	14
3	86	14
4	85	15
5	85	15
6	86	14
7	85	15
8	85	15
9	84	16
10	84	16
11	84	16
12	84	16
13	82	18
14	82	18
15	82	18
16	82	18
17	82	18
18	82	18
19	82	18
20	81	19
21	81	19
22	81	19
23	81	19
24	80	20
25	80	20
26	80	20
27	78	22
28	78	22
29	77	23
30	76	24

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

	Dry (%)
1	100
2	100
3	100
4	100
5	100
6	100
7	100
8	100
9	100
10	100
11	100
12	100
13	100
14	100
15	100
16	100
17	100
18	100
19	100
20	100
21	100
22	100
23	100
24	100
25	100
26	100
27	100
28	100
29	100
30	100