Portlaoise weather in September

In September, Portlaoise sees average daytime highs of 16°C and overnight lows near 10°C, with 62 mm of rain across 10.9 wet days and about 12.4 hours of daylight. It is the 4th-warmest and 10th-wettest month of the year here.

Highs ease over the month, from about 17°C in the first days to 15°C by the end. The sky is clear or mostly clear about 7% of the time in September, and the air most often feels dry.

Daylight stretches from about 13 h 30 min at the start of September to 11 h 24 min by month's end. Set against the rest of the year, September is Portlaoise's 9th-clearest and 9th-windiest month. For the whole year in context, see Portlaoise's year-round climate.

Daytime high: 16°; 4th warmest
Overnight low: 10°; 9th coldest
Rainfall: 62 mm; 10.9 wet days
Daylight: 12 h 24 min; 6:11 AM – 6:36 PM
Cloud cover: 79%; 9th clearest
Wind: 13 km/h; 9th windiest
Solar energy: 2.65 kWh/m²
Travel score: 4.8; out of 10

Portlaoise is county town of County Laois, Ireland.

Density: 1,942/km²; people per km²
Founded: 1557

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

← August Portlaoise 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 ease over the month, from about 17°C in the first days to 15°C by the end.

A typical September day in Portlaoise reaches about 16°C in the afternoon and slips back to 10°C overnight — a 7°C spread between the day's warmth and the night's chill. On most days the high lands between 14°C and 19°C. Set against its neighbours, September runs about 2°C cooler than August and about 3°C warmer than 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)	18	18	17	17	17	17	17	17	17	17	17	17	17	17	16	16	16	16	16	16	16	16	16	16	15	15	15	15	15	15
Avg low (°C)	11	11	11	11	11	11	11	10	10	10	10	10	10	10	10	10	10	10	10	9	9	9	9	9	9	9	9	9	9	9

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

How September really feels in Portlaoise

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.

Portlaoise weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 10th-wettest month here — the current month is highlighted below.

Month	High / Low (°C)	Rainfall (mm)	Wet days	Snow days	Daylight (hours)	Travel score
Jan	8° / 3°	71	13.3	0.6	7.9	1.1
Feb	8° / 3°	59	11.7	0.9	9.5	1.2
Mar	10° / 4°	60	12.2	0.7	11.5	2.0
Apr	12° / 5°	63	12.6	0.1	13.6	2.9
May	15° / 7°	64	12.6	0	15.5	4.0
Jun	17° / 10°	70	12.1	0	16.6	5.0
Jul	19° / 12°	66	12.5	0	16.2	5.3
Aug	18° / 12°	74	12.6	0	14.5	5.3
Sep	16° / 10°	62	10.9	0	12.4	4.8
Oct	13° / 7°	78	12.7	0	10.3	3.3
Nov	10° / 5°	79	12.4	0.1	8.4	2.0
Dec	8° / 3°	79	13.6	0.6	7.4	1.2

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 7% 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 81%.

	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 (%)	17	17	17	17	17	17	17	17	18	18	18	18	18	18	18	18	19	20	20	20	20	20	21	20	20	20	21	20	20	21
Cloudier (%)	83	83	83	83	83	83	83	83	82	82	82	82	82	82	82	82	81	80	80	80	80	80	79	80	80	80	79	80	80	79

	Clearer (%)	Cloudier (%)
1	17	83
2	17	83
3	17	83
4	17	83
5	17	83
6	17	83
7	17	83
8	17	83
9	18	82
10	18	82
11	18	82
12	18	82
13	18	82
14	18	82
15	18	82
16	18	82
17	19	81
18	20	80
19	20	80
20	20	80
21	20	80
22	20	80
23	21	79
24	20	80
25	20	80
26	20	80
27	21	79
28	20	80
29	20	80
30	21	79

Chance of precipitation in September

Any precipitation

Portlaoise gets around 62 mm of rain over 10.9 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 36% and peaks near 41% 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 (%)	32	32	33	33	33	33	34	34	35	35	35	35	35	35	35	35	35	36	36	36	37	37	38	39	40	40	41	41	41	41

	Rain chance (%)
1	32
2	32
3	33
4	33
5	33
6	33
7	34
8	34
9	35
10	35
11	35
12	35
13	35
14	35
15	35
16	35
17	35
18	36
19	36
20	36
21	37
22	37
23	38
24	39
25	40
26	40
27	41
28	41
29	41
30	41

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 84% 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 (%)	77	77	77	78	78	78	79	79	80	81	81	83	84	84	86	86	86	86	86	87	87	87	87	88	88	88	88	89	89	90
Comfortable (%)	20	20	20	19	19	19	18	18	17	16	16	15	14	14	13	13	13	13	13	13	13	13	13	12	12	12	12	11	11	10
Humid (%)	3	3	3	3	3	3	3	3	3	3	3	2	2	2	1	1	1	1	1	0	0	0	0	0	0	0	0	0	0	0

	Dry (%)	Comfortable (%)	Humid (%)
1	77	20	3
2	77	20	3
3	77	20	3
4	78	19	3
5	78	19	3
6	78	19	3
7	79	18	3
8	79	18	3
9	80	17	3
10	81	16	3
11	81	16	3
12	83	15	2
13	84	14	2
14	84	14	2
15	86	13	1
16	86	13	1
17	86	13	1
18	86	13	1
19	86	13	1
20	87	13	0
21	87	13	0
22	87	13	0
23	87	13	0
24	88	12	0
25	88	12	0
26	88	12	0
27	88	12	0
28	89	11	0
29	89	11	0
30	90	10	0

Wind in September

Winds average 13 km/h in September.

Across September, daily wind ranges from about 13 km/h on the calmest days to 14 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)	13	13	13	13	13	13	13	13	13	14	14	14	14	14	14	14	14	14	14	14	14	14	14	14	14	14	14	14	14	14
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	13	light breeze
2	13	light breeze
3	13	light breeze
4	13	light breeze
5	13	light breeze
6	13	light breeze
7	13	light breeze
8	13	light breeze
9	13	light breeze
10	14	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	14	light breeze
20	14	light breeze
21	14	light breeze
22	14	light breeze
23	14	light breeze
24	14	light breeze
25	14	light breeze
26	14	light breeze
27	14	light breeze
28	14	light breeze
29	14	light breeze
30	14	light breeze

Sunrise & sunset in September

DaylightNight

Daylight runs from about 13 h 30 min at the start of September to 11 h 24 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 126 minutes over September. Sunrise moves from 5:45 AM to 6:36 AM, and sunset from 7:13 PM to 6:01 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)	13.5	13.4	13.3	13.3	13.2	13.1	13.1	13.0	12.9	12.8	12.8	12.7	12.6	12.6	12.5	12.4	12.3	12.3	12.2	12.1	12.1	12.0	11.9	11.8	11.8	11.7	11.6	11.6	11.5	11.4
Sunrise (AM)	5:45	5:47	5:48	5:50	5:52	5:54	5:55	5:57	5:59	6:01	6:02	6:04	6:06	6:08	6:09	6:11	6:13	6:15	6:17	6:18	6:20	6:22	6:24	6:25	6:27	6:29	6:31	6:33	6:34	6:36
Sunset (PM)	7:13	7:11	7:08	7:06	7:03	7:01	6:58	6:56	6:53	6:51	6:48	6:46	6:43	6:41	6:38	6:36	6:33	6:31	6:28	6:26	6:23	6:21	6:18	6:16	6:13	6:11	6:08	6:06	6:03	6:01

	Daylight (h)	Sunrise (AM)	Sunset (PM)
1	13.5	5:45	7:13
2	13.4	5:47	7:11
3	13.3	5:48	7:08
4	13.3	5:50	7:06
5	13.2	5:52	7:03
6	13.1	5:54	7:01
7	13.1	5:55	6:58
8	13.0	5:57	6:56
9	12.9	5:59	6:53
10	12.8	6:01	6:51
11	12.8	6:02	6:48
12	12.7	6:04	6:46
13	12.6	6:06	6:43
14	12.6	6:08	6:41
15	12.5	6:09	6:38
16	12.4	6:11	6:36
17	12.3	6:13	6:33
18	12.3	6:15	6:31
19	12.2	6:17	6:28
20	12.1	6:18	6:26
21	12.1	6:20	6:23
22	12.0	6:22	6:21
23	11.9	6:24	6:18
24	11.8	6:25	6:16
25	11.8	6:27	6:13
26	11.7	6:29	6:11
27	11.6	6:31	6:08
28	11.6	6:33	6:06
29	11.5	6:34	6:03
30	11.4	6:36	6:01

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 2.65 kWh/m².

For context, solar energy here swings from a low near 0.53 kWh/m² to a high of 4.81 kWh/m² in June across the year — September's 2.65 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)	3.2	3.2	3.1	3.1	3.0	3.0	3.0	2.9	2.9	2.9	2.8	2.8	2.8	2.7	2.7	2.7	2.6	2.6	2.5	2.5	2.5	2.4	2.4	2.3	2.3	2.3	2.2	2.2	2.1	2.1
Level	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate

	Solar energy (kWh/m²)	Level
1	3.2	Moderate
2	3.2	Moderate
3	3.1	Moderate
4	3.1	Moderate
5	3.0	Moderate
6	3.0	Moderate
7	3.0	Moderate
8	2.9	Moderate
9	2.9	Moderate
10	2.9	Moderate
11	2.8	Moderate
12	2.8	Moderate
13	2.8	Moderate
14	2.7	Moderate
15	2.7	Moderate
16	2.7	Moderate
17	2.6	Moderate
18	2.6	Moderate
19	2.5	Moderate
20	2.5	Moderate
21	2.5	Moderate
22	2.4	Moderate
23	2.4	Moderate
24	2.3	Moderate
25	2.3	Moderate
26	2.3	Moderate
27	2.2	Moderate
28	2.2	Moderate
29	2.1	Moderate
30	2.1	Moderate

Planning a trip in September

Is September a good time to visit Portlaoise?

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

4.8

Sightseeing

4th-best month of the year

0.8

Beach & pool

4th-best month of the year

September is a reasonable time to visit Portlaoise for sightseeing.

What to pack for Portlaoise in September

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

In September, Portlaoise sees daytime highs around 16°C and nights near 10°C. Worth packing: a warm layer and rain gear. About 11 days see rain.

a warm layerrain gear

UV index in Portlaoise in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 4 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Portlaoise peaks around August 13 at about 6 (high) — a little sun protection helps at midday. It bottoms out near January 1 at about 1 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 6 months of the year.

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
UV index (midday)	1	1	3	4	5	5	5	6	4	2	1	1
Level	Low	Low	Moderate	Moderate	High	High	High	High	Moderate	Low	Low	Low

	UV index (midday)	Level
Jan	1	Low
Feb	1	Low
Mar	3	Moderate
Apr	4	Moderate
May	5	High
Jun	5	High
Jul	5	High
Aug	6	High
Sep	4	Moderate
Oct	2	Low
Nov	1	Low
Dec	1	Low

Location & terrain

Where is Portlaoise?

Portlaoise sits at 53.0°N, 7.3°W, 101 m above sea level, in Ireland. The nearest listed city is Tullamore, 29 km away.

Topography around Portlaoise

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

Within 3 km, the terrain around Portlaoise has only modest variations in elevation — a maximum elevation change of 55 m around an average of 101 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 453 m; within 80 km, large variations in elevation — a maximum elevation change of 931 m.

The land around Portlaoise is covered by grassland (62%) within 3 km, grassland (68%) within 16 km, and grassland (76%) within 80 km.

3 km

55 m

grassland 62%

16 km

453 m

grassland 68%

80 km

931 m

grassland 76%

treesgrasslandcroplandartificial surfaceswater

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

September weather nearby: Tullamore 29 km · Carlow 33 km · Droichead Nua 37 km · Kilkenny 42 km · Naas 47 km · An Muileann gCearr 55 km · Athlone 61 km · Celbridge 61 km

Ireland travel facts

Travel advisory: Level 1; Exercise Normal Precautions
Power plugs: Type G; 230 V · 50 Hz
Prices: ≈ 85% of US; price level, 2025
GDP per capita: $131,592; 2025
Happiness: 6.9 / 10; World Happiness, 2025
Safe drinking water: 96%; of population, 2024
Homicide rate: 0.7; per 100k, 2023
Road deaths: 3.1; per 100k/yr, 2019
Income group: High; World Bank
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 Portlaoise (53.0344°, -7.2998°, elevation 101 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	18	11
2	18	11
3	17	11
4	17	11
5	17	11
6	17	11
7	17	11
8	17	10
9	17	10
10	17	10
11	17	10
12	17	10
13	17	10
14	17	10
15	16	10
16	16	10
17	16	10
18	16	10
19	16	10
20	16	9
21	16	9
22	16	9
23	16	9
24	16	9
25	15	9
26	15	9
27	15	9
28	15	9
29	15	9
30	15	9

	Clearer (%)	Cloudier (%)
1	17	83
2	17	83
3	17	83
4	17	83
5	17	83
6	17	83
7	17	83
8	17	83
9	18	82
10	18	82
11	18	82
12	18	82
13	18	82
14	18	82
15	18	82
16	18	82
17	19	81
18	20	80
19	20	80
20	20	80
21	20	80
22	20	80
23	21	79
24	20	80
25	20	80
26	20	80
27	21	79
28	20	80
29	20	80
30	21	79

	Rain chance (%)
1	32
2	32
3	33
4	33
5	33
6	33
7	34
8	34
9	35
10	35
11	35
12	35
13	35
14	35
15	35
16	35
17	35
18	36
19	36
20	36
21	37
22	37
23	38
24	39
25	40
26	40
27	41
28	41
29	41
30	41

	Dry (%)	Comfortable (%)	Humid (%)
1	77	20	3
2	77	20	3
3	77	20	3
4	78	19	3
5	78	19	3
6	78	19	3
7	79	18	3
8	79	18	3
9	80	17	3
10	81	16	3
11	81	16	3
12	83	15	2
13	84	14	2
14	84	14	2
15	86	13	1
16	86	13	1
17	86	13	1
18	86	13	1
19	86	13	1
20	87	13	0
21	87	13	0
22	87	13	0
23	87	13	0
24	88	12	0
25	88	12	0
26	88	12	0
27	88	12	0
28	89	11	0
29	89	11	0
30	90	10	0

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

	Clearer (%)	Cloudier (%)
1	17	83
2	17	83
3	17	83
4	17	83
5	17	83
6	17	83
7	17	83
8	17	83
9	18	82
10	18	82
11	18	82
12	18	82
13	18	82
14	18	82
15	18	82
16	18	82
17	19	81
18	20	80
19	20	80
20	20	80
21	20	80
22	20	80
23	21	79
24	20	80
25	20	80
26	20	80
27	21	79
28	20	80
29	20	80
30	21	79

	Rain chance (%)
1	32
2	32
3	33
4	33
5	33
6	33
7	34
8	34
9	35
10	35
11	35
12	35
13	35
14	35
15	35
16	35
17	35
18	36
19	36
20	36
21	37
22	37
23	38
24	39
25	40
26	40
27	41
28	41
29	41
30	41

	Dry (%)	Comfortable (%)	Humid (%)
1	77	20	3
2	77	20	3
3	77	20	3
4	78	19	3
5	78	19	3
6	78	19	3
7	79	18	3
8	79	18	3
9	80	17	3
10	81	16	3
11	81	16	3
12	83	15	2
13	84	14	2
14	84	14	2
15	86	13	1
16	86	13	1
17	86	13	1
18	86	13	1
19	86	13	1
20	87	13	0
21	87	13	0
22	87	13	0
23	87	13	0
24	88	12	0
25	88	12	0
26	88	12	0
27	88	12	0
28	89	11	0
29	89	11	0
30	90	10	0

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

	Clearer (%)	Cloudier (%)
1	17	83
2	17	83
3	17	83
4	17	83
5	17	83
6	17	83
7	17	83
8	17	83
9	18	82
10	18	82
11	18	82
12	18	82
13	18	82
14	18	82
15	18	82
16	18	82
17	19	81
18	20	80
19	20	80
20	20	80
21	20	80
22	20	80
23	21	79
24	20	80
25	20	80
26	20	80
27	21	79
28	20	80
29	20	80
30	21	79

	Rain chance (%)
1	32
2	32
3	33
4	33
5	33
6	33
7	34
8	34
9	35
10	35
11	35
12	35
13	35
14	35
15	35
16	35
17	35
18	36
19	36
20	36
21	37
22	37
23	38
24	39
25	40
26	40
27	41
28	41
29	41
30	41

	Dry (%)	Comfortable (%)	Humid (%)
1	77	20	3
2	77	20	3
3	77	20	3
4	78	19	3
5	78	19	3
6	78	19	3
7	79	18	3
8	79	18	3
9	80	17	3
10	81	16	3
11	81	16	3
12	83	15	2
13	84	14	2
14	84	14	2
15	86	13	1
16	86	13	1
17	86	13	1
18	86	13	1
19	86	13	1
20	87	13	0
21	87	13	0
22	87	13	0
23	87	13	0
24	88	12	0
25	88	12	0
26	88	12	0
27	88	12	0
28	89	11	0
29	89	11	0
30	90	10	0