Irish Sea water temperature
Irish Sea, Portmarnock · Sea/Coast
The current water temperature at Irish Sea is 13.9 °C (as of October 16, 2026, source: Open-Meteo marine model).
The sea lags the air by weeks: the warmest water often arrives after the warmest days. Measured buoy values show this honestly.
Water quality
Official EPA rating: excellentMeasurement series & statistics
This measurement series includes 798 data points since August 17, 2026.
Lowest recorded value: 13.9 °C on October 16, 2026 · highest value: 19.0 °C on August 17, 2026.
In October, temperatures have ranged between 13.9 °C and 15.4 °C.
The current value is 0.8 °C below the October average of this series.
Nearby waters
More measuring points: Irish Sea
Frequently asked questions
Can you swim at Irish Sea right now?
The current water temperature is 13.9 °C. See live swimming conditions, weather and quality in the BrrChecker app.
How warm is the water at Irish Sea?
Currently 13.9 °C (updated continuously).
How warm is at Irish Sea in October?
In October, the water temperature recently averaged 14.7 °C.
When is the water warmest at Irish Sea?
Across the measurement record, August is on average the warmest month (17.7 °C).
How is the water quality at Irish Sea?
The official classification is: excellent.
