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Warmest sea in Ireland in September

169 coastal locations in Ireland ranked by their typical September sea temperature. Region-wide average in September: 15.4°C. The top of the list is where to find the warmest swimming this month.

Warmest in September

Ballycotton

16.1°C September mean in Ireland

Regional September average

15.4°C

across all 169 coastal locations in Ireland

Vs annual mean

+3.1°C

above the year-round regional average

What the Ireland sea feels like in September

At this temperature, water will feel cold compared to a swimming pool, but with a bit of experience and practice most people will find the water relatively comfortable to swim in.

Ireland monthly average 9.0°C to 16.0°C
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  • Warmest month August 16.0°C
  • Coldest month February 9.0°C
  • Annual mean 12.3°C
  • Months above 20°C 0 of 12

Where September fits in the year

September sits inside the regional pattern shown on the left. Pick a different month to see how the ranking shifts.

All twelve Ireland month rankings:

Ireland sea temperature map (live)

The map shows today's latest reading at every Ireland location. The list below is based on the typical September mean, useful for trip planning weeks or months ahead.

Zoom in to see individual locations. Click a pin for water temperatures. View list →
°C -2 0 1 3 5 7 9 11 13 15 17 19 21 24 27 30 35

Top 50 warmest Ireland locations in September

Sorted by the typical September mean built from a decade of daily readings at each location. Click any place for its 30-day chart, monthly profile, and full 10-year history.

# Location September mean
1 Ballycotton County Cork 16.1°C
2 Cork City County Cork 16.0°C
3 Crosshaven County Cork 16.0°C
4 Marino Point County Cork 16.0°C
5 Ringaskiddy County Cork 16.0°C
6 Roberts Cove County Cork 16.0°C
7 Courtmacsherry County Cork 15.9°C
8 Castletownshend County Cork 15.9°C
9 Clonakilty Bay County Cork 15.9°C
10 Ardmore 15.9°C
11 Youghal 15.8°C
12 Baltimore County Cork 15.8°C
13 Garryvoe 15.8°C
14 Carrigaholt County Clare 15.8°C
15 Coney Island County Clare 15.8°C
16 Foynes Island County Limerick 15.8°C
17 Gaillimh County Galway 15.8°C
18 Galway City County Galway 15.8°C
19 Limerick Harbour County Limerick 15.8°C
20 Liscannor County Clare 15.8°C
21 Mellon Point County Limerick 15.8°C
22 Oranmore County Galway 15.8°C
23 Tarbert Island County Kerry 15.8°C
24 Garretstown Beach 15.8°C
25 Inishmore (Killeany Bay) County Galway 15.8°C
Show 25 more ▸
26 Kilbrittain 15.8°C
27 Kilkieran County Galway 15.8°C
28 Kinsale 15.8°C
29 Courtown County Wexford 15.8°C
30 Carrigaline 15.8°C
31 Cobh 15.8°C
32 Cork 15.8°C
33 Myrtleville 15.8°C
34 Passage West 15.8°C
35 Trá Mhór County Waterford 15.7°C
36 Clonea 15.7°C
37 Dungarvan 15.7°C
38 Clonakilty 15.7°C
39 Crookhaven County Cork 15.7°C
40 Dunmanus County Cork 15.7°C
41 Ballyheige County Kerry 15.7°C
42 Kilbaha Bay County Clare 15.7°C
43 Loch Garman County Wexford 15.7°C
44 Rosslare Europort County Wexford 15.7°C
45 Wexford Harbour County Wexford 15.7°C
46 Baginbun Head County Wexford 15.7°C
47 Cheekpoint County Waterford 15.7°C
48 Fethard-on-Sea County Wexford 15.7°C
49 Kilmokea Point County Wexford 15.7°C
50 New Ross County Wexford 15.7°C

Coldest 10 in Ireland in September

Same data the other way. Helpful if you want to know which Ireland coasts to avoid for swimming in September.

# Location September mean
1 Moville 14.7°C
2 Buncrana 14.8°C
3 Inishtrahull County Donegal 14.8°C
4 Belmullet 14.8°C
5 Blackrock 14.8°C
6 Clogherhead 14.8°C
7 Dalkey 14.8°C
8 Donabate 14.8°C
9 Dun Laoghaire 14.8°C
10 Forty Foot 14.8°C

More on this region