Can you swim at Derrynane in September? — 15.0°C water
Cool — short dips or a shorty wetsuit
Average sea · September
15.0°C
Live water now
…
Recommended wetsuit
4/3mm fullsuit
mild
Cool. 15.0°C in September means short dips for most people. A 2 mm shorty or 3/2 mm wetsuit transforms the experience.
Monthly averages set expectations, but the specific beach today depends on wind, swell and recent weather. Check the live value at the top of this page or open the Derrynane live page for full conditions.
Frequently asked questions
What is the average sea temperature at Derrynane in September?
Derrynane averages 15.0°C in September, based on long-run climatology for the Celtic Sea.
Is the sea warm enough to swim at Derrynane in September?
Not without thermal protection — a wetsuit is recommended at 15.0°C.
