South Dublin weather in September

In September, South Dublin sees average daytime highs of 16°C and overnight lows near 10°C, with 70 mm of rain across 12.3 wet days and about 12.4 hours of daylight. It is the 4th-warmest and 7th-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 9% 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 South Dublin's 10th-clearest and 8th-windiest month. For the whole year in context, see South Dublin's year-round climate.

Daytime high
16°
4th warmest
Overnight low
10°
9th coldest
Rainfall
70 mm
12.3 wet days
Daylight
12 h 24 min
6:07 AM – 6:32 PM
Cloud cover
77%
10th clearest
Wind
15 km/h
8th windiest
Solar energy
2.94 kWh/m²
Travel score
4.5
out of 10
Air quality
Good
PM2.5 7.8 µg/m³ · 2019

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

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 South Dublin reaches about 16°C in the afternoon and slips back to 10°C overnight — a 6°C spread between the day's warmth and the night's chill. On most days the high lands between 13°C and 18°C. Set against its neighbours, September runs about 2°C cooler than August and about 3°C warmer than October.

10°15°20°151015202530
Avg high (°C)Avg low (°C)
11711
21711
31711
41711
51711
61711
71711
81711
91611
101611
111611
121611
131611
141610
151610
161610
171610
181610
191610
201510
211510
221510
231510
241510
251510
261510
271510
28159
29159
30159

How September really feels in South Dublin

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
0
heat index over the day's high
Days feeling ≤ C
0
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.

South Dublin weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 7th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan / 6913.20.97.81.0
Feb / 5711.81.29.41.1
Mar / 5912.21.111.51.7
Apr11° / 6613.80.113.72.4
May14° / 6613.6015.63.5
Jun16° / 10°7313.2016.64.5
Jul18° / 12°7614.8016.24.9
Aug18° / 12°7813.7014.65.1
Sep16° / 10°7012.3012.44.5
Oct13° / 7812.4010.33.2
Nov10° / 8513.20.38.41.9
Dec / 7612.90.87.41.2

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 9% 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 78%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
11981
21981
32080
42080
52080
62179
72278
82278
92278
102179
112278
122278
132278
142377
152377
162377
172377
182377
192377
202278
212278
222278
232278
242278
252278
262278
272179
282179
292278
302278

Chance of precipitation in September

Any precipitation

South Dublin gets around 70 mm of rain over 12.3 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 40% and peaks near 43% on the wettest days. The odds climb toward the end of the month.

0%10%20%30%40%50%151015202530
Rain chance (%)
136
237
337
437
538
638
739
839
940
1040
1140
1240
1340
1440
1540
1640
1740
1840
1940
2040
2141
2241
2342
2442
2542
2643
2743
2843
2943
3043

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 85% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)
177203
277203
377203
478193
578193
679183
779183
880182
981172
1082162
1182162
1283152
1385141
1485141
1586131
1686131
1786131
1888120
1988120
2088120
2188120
2288120
2389110
2489110
2589110
2689110
2789110
2890100
2990100
309190

Wind in September

Winds average 15 km/h in September.

Across September, daily wind ranges from about 15 km/h on the calmest days to 16 km/h at its breeziest. It stays fairly steady from day to day.

05101520151015202530
Wind speed (km/h)Feels
115light breeze
215light breeze
315light breeze
415light breeze
515light breeze
615light breeze
715light breeze
815light breeze
915light breeze
1015light breeze
1115light breeze
1216light breeze
1316light breeze
1416light breeze
1516light breeze
1616light breeze
1716light breeze
1816light breeze
1916light breeze
2016light breeze
2116light breeze
2216light breeze
2316light breeze
2416light breeze
2516light breeze
2616light breeze
2716light breeze
2816light breeze
2916light breeze
3016light 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 5:41 AM to 6:33 AM, and sunset from 7:10 PM to 5:57 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
113.55:417:10
213.45:427:07
313.35:447:05
413.35:467:02
513.25:487:00
613.15:496:57
713.15:516:55
813.05:536:52
912.95:556:50
1012.85:576:47
1112.85:586:45
1212.76:006:42
1312.66:026:40
1412.66:046:37
1512.56:056:35
1612.46:076:32
1712.36:096:30
1812.36:116:27
1912.26:136:25
2012.16:146:22
2112.16:166:19
2212.06:186:17
2311.96:206:14
2411.86:226:12
2511.86:236:09
2611.76:256:07
2711.66:276:04
2811.56:296:02
2911.56:315:59
3011.46:335:57

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 2.94 kWh/m².

For context, solar energy here swings from a low near 0.56 kWh/m² to a high of 5.27 kWh/m² in June across the year — September's 2.94 kWh/m² falls in the middle.

01234151015202530
Solar energy (kWh/m²)Level
13.5Moderate
23.5Moderate
33.5Moderate
43.4Moderate
53.4Moderate
63.3Moderate
73.3Moderate
83.3Moderate
93.2Moderate
103.2Moderate
113.1Moderate
123.1Moderate
133.1Moderate
143.0Moderate
153.0Moderate
163.0Moderate
172.9Moderate
182.9Moderate
192.8Moderate
202.8Moderate
212.7Moderate
222.7Moderate
232.6Moderate
242.6Moderate
252.5Moderate
262.5Moderate
272.5Moderate
282.4Moderate
292.4Moderate
302.3Moderate
Planning a trip in September

Is September a good time to visit South Dublin?

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

4.5
Sightseeing
3rd-best month of the year
0.5
Beach & pool
4th-best month of the year

September is a reasonable time to visit South Dublin for sightseeing.

What to pack for South Dublin in September

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

In September, South Dublin sees daytime highs around 16°C and nights near 10°C. Worth packing: a warm layer and rain gear. About 12 days see rain.

a warm layerrain gear

Sea temperature near South Dublin in September

The nearest coast averages about 15°C in September — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea at the nearest coast (about 17 km away) is warmest in August at about 15°C and coldest in March near 8°C.

The water stays below 20°C all year — cool enough that most swimmers want a wetsuit.

10°15°JanFebMarAprMayJunJulAugSepOctNovDecbracingcool
Sea temperature (°C)Comfort
Jan9Bracing
Feb8Bracing
Mar8Bracing
Apr9Bracing
May11Bracing
Jun13Bracing
Jul15Bracing
Aug15Cool
Sep15Bracing
Oct13Bracing
Nov12Bracing
Dec11Bracing

UV index in South Dublin 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 South Dublin 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.

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighModerateLowAug 13UV 6Jan 1UV 1
UV index (midday)Level
Jan1Low
Feb1Low
Mar3Moderate
Apr4Moderate
May5High
Jun6High
Jul5High
Aug6High
Sep4Moderate
Oct2Low
Nov1Low
Dec1Low
Location & terrain

Where is South Dublin?

South Dublin sits at 53.3°N, 6.3°W, 80 m above sea level, in Ireland. The nearest listed city is Tallaght, 2.0 km away.

Topography around South Dublin

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

Within 3 km, the terrain around South Dublin has only modest variations in elevation — a maximum elevation change of 152 m around an average of 85 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 754 m; within 80 km, large variations in elevation — a maximum elevation change of 946 m.

The land around South Dublin is covered by artificial surfaces (54%) and grassland (27%) within 3 km, grassland (44%), trees (22%) and artificial surfaces (22%) within 16 km, and grassland (53%) and water (25%) within 80 km.

3 km
152 m
16 km
754 m
80 km
946 m
treesgrasslandcroplandartificial surfaceswater
September weather nearby: Tallaght 2.0 km · Templeogue 2.0 km · Rathfarnham 4.0 km · Dublin 8.0 km · Sandyford 8.0 km · Lucan 10 km · Blanchardstown 11 km · Finglas 11 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
Roman Catholic 69%none 15%Protestant 4%Orthodox 2%

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 South Dublin (53.2903°, -6.3415°, elevation 80 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. Sea temperatures are the NOAA OISST v2.1 1991–2020 monthly climatology (public domain), sampled at the nearest ocean point. 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).