NOAA SATELLITE DATA (1991–2020 30-YEAR CLIMATOLOGY)
IE

Ireland Sea Temperature in September

Historical 30-year sea surface temperatures across 11 coastlines in Ireland for September. Derived from NOAA 0.25° blended satellite and in-situ marine observations.

Climatology Notice: Temperatures represent the 30-year long-term historical average (1991–2020 normal), not a live single-day sensor forecast.
15.2°C
Bracing / Crispaverage across 11 surveyed coastlines in Ireland, September
  • Ranges 14.5°C at Ballymastocker Bay to 15.5°C at Keem Bay.
  • No coastline in Ireland reaches 21°C in any month — this is wetsuit or cold-water swimming.
  • 0.7°C cooler than Ireland’s August peak of 15.9°C (see August).

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The September Thermal Lag Advantage

Because seawater has a high specific heat capacity, it acts as a massive thermal battery. Southern European and Mediterranean basins absorb solar energy all summer, reaching maximum heat storage by late August. In September, while air temperatures drop, the water releases heat slowly, which creates sea temperatures that are typically 3°C to 5°C warmer than in June.

CYPRUS (AYIA NAPA / PROTARAS)
27.5°C
Effortless swimming
TURKEY (ANTALYA / KAŞ)
27.3°C
Warm bathwater
GREECE (CRETE / RHODES)
25.4°C
Extended season
MALTA & GOZO
26.1°C
Crystal clear
Field Guides:October Swimming Guide November Swimming Guide

Ireland Beaches in September

Individual coordinate lookups from NOAA 0.25° marine grid.

Showing 11 coastlines
Keem Bay
#1 in September
15.5°C
Ireland flagCounty Mayo (Achill Island), Ireland
● Bracing / Crisp
NOAA Season Curve (May–Oct):
M
12.5°
J
14.6°
J
15.9°
A
16.4°
S
15.5°
O
13.8°
N
11.9°
View Full Beach Guide
Derrynane Beach
#2 in September
15.5°C
Ireland flagCounty Kerry (Ring of Kerry), Ireland
● Bracing / Crisp
NOAA Season Curve (May–Oct):
M
12.5°
J
14.6°
J
15.9°
A
16.4°
S
15.5°
O
13.8°
N
11.9°
View Full Beach Guide
Coumeenoole Beach
#4 in September
15.5°C
Ireland flagCounty Kerry (Dingle Peninsula), Ireland
● Bracing / Crisp
NOAA Season Curve (May–Oct):
M
12.5°
J
14.6°
J
15.9°
A
16.4°
S
15.5°
O
13.8°
N
11.9°
View Full Beach Guide
Inchydoney
#5 in September
15.5°C
Ireland flagCounty Cork, Ireland
● Bracing / Crisp
NOAA Season Curve (May–Oct):
M
11.7°
J
14.1°
J
15.8°
A
16.2°
S
15.5°
O
13.9°
N
11.9°
View Full Beach Guide
Barleycove Beach
#6 in September
15.3°C
Ireland flagMizen Peninsula, West Cork, Ireland
● Bracing / Crisp
NOAA Season Curve (May–Oct):
M
11.8°
J
14.0°
J
15.5°
A
16.0°
S
15.3°
O
13.8°
N
11.9°
View Full Beach Guide
Banna Strand
#8 in September
15.0°C
Ireland flagCounty Kerry, Ireland
● Bracing / Crisp
NOAA Season Curve (May–Oct):
M
11.6°
J
13.8°
J
15.3°
A
15.8°
S
15.0°
O
13.5°
N
11.9°
View Full Beach Guide
Inch Beach
#9 in September
15.0°C
Ireland flagDingle Peninsula, County Kerry, Ireland
● Bracing / Crisp
NOAA Season Curve (May–Oct):
M
11.6°
J
13.8°
J
15.3°
A
15.8°
S
15.0°
O
13.5°
N
11.9°
View Full Beach Guide
Strandhill Beach
#10 in September
14.9°C
Ireland flagStrandhill, County Sligo, Ireland
● Bracing / Crisp
NOAA Season Curve (May–Oct):
M
11.1°
J
13.3°
J
14.9°
A
15.5°
S
14.9°
O
13.3°
N
11.6°
View Full Beach Guide

Explore Sea Temperatures by Country

Spain(23.6°C)Italy(25.9°C)Turkey(27.3°C)France(22.4°C)Greece(25.4°C)Cyprus(27.7°C)Croatia(25.2°C)Albania(25.5°C)Montenegro(25.7°C)Malta(26.7°C)Bulgaria(25.1°C)Romania(24.7°C)Slovenia(25.4°C)Portugal(20.7°C)Poland(19°C)Sweden(18.3°C)Netherlands(18.5°C)Bosnia & Herzegovina(25.2°C)Monaco(24.6°C)Latvia(18.5°C)Estonia(18°C)Lithuania(18.8°C)Germany(18.6°C)Denmark(18°C)Norway(15.3°C)Belgium(18.7°C)Faroe Islands(10.9°C)United Kingdom(16.1°C)Ireland(15.9°C)Iceland(10.9°C)Finland(16.6°C)