UK sea temperatures, and what to wear in them
UK sea temperatures run from about 6°C in late winter to about 18°C in late summer. A swimsuit is enough for most people from June to October. From November to May, add a long sleeve layer, gloves and boots, or wear a wetsuit for longer swims.
Month by month
| Month | Sea temperature | What to wear |
|---|---|---|
| January to March | 6 to 11°C | The coldest water of the year. Bonded long sleeve suit or wetsuit, plus gloves, boots and a hat. Keep it short |
| April and May | 8 to 12°C | Still cold, though the air is kinder. Same kit as winter |
| June | 12 to 14°C | A swimsuit for dips. A long sleeve top if you're staying in |
| July to September | 14 to 18°C | A swimsuit. The sea is at its warmest in August and September |
| October | 13 to 17°C | A swimsuit, with a long sleeve layer as the month goes on |
| November | 11 to 15°C | Long sleeves. Gloves and boots come back out |
| December | 9 to 12°C | Bonded suit or wetsuit, gloves, boots and a hat |
These are averages for English coastal waters. Scotland and the North Sea run colder, and lakes and rivers change faster than the sea in both directions.
Why 15°C matters
The RNLI defines anything below 15°C as cold water, and puts the average UK and Ireland sea temperature at 12°C. So for most of the year, most of our water counts as cold.
It depends on you
How long you stay in matters as much as the month. So does how often you swim, because your body adapts with regular dips. Start in late summer if you can, and keep going as the water cools.
Our cold water pieces
The Bonded Long Sleeve Swimsuit and the Bonded Long Sleeve Swim Top are in our cold water collection while stock lasts. For help choosing, see who long sleeve swimsuits are for and how they should fit, or bonded swimsuit or wetsuit.