Celtic Sea water temperature
Celtic Sea, South Pembrokeshire · Sea/Coast
The current water temperature at Celtic Sea is 17.7 °C (as of September 20, 2026, source: Cefas).
The sea lags the air by weeks: the warmest water often arrives after the warmest days. Measured buoy values show this honestly.
Measurement series & statistics
This measurement series includes 144 data points since September 6, 2026.
Lowest recorded value: 17.6 °C on September 16, 2026 · highest value: 18.4 °C on September 7, 2026.
In September, temperatures have ranged between 17.6 °C and 18.4 °C.
The current value is 0.2 °C below the September average of this series.
Nearby waters
More measuring points: Celtic Sea
Frequently asked questions
Can you swim at Celtic Sea right now?
The current water temperature is 17.7 °C. See live swimming conditions, weather and quality in the BrrChecker app.
How warm is the water at Celtic Sea?
Currently 17.7 °C (updated continuously).
How warm is at Celtic Sea in September?
In September, the water temperature recently averaged 17.9 °C.
