Map of UK sea temperatures in October, warmest off Cornwall and the south coast

UK Sea Temperatures By Month (And What To Actually Wear)

Everyone asks how cold the sea is. Nobody likes the answer, which is: colder than you think, and at the wrong time of year.

The UK sea runs about two months behind the air. It keeps losing heat after Christmas and bottoms out in March, when the daffodils are out and you have started telling people it is nearly spring. It peaks in late August and September, after the holidays have ended and the car parks have emptied. Plan your wetsuit around the water, not the calendar.

UK sea temperatures by month

Long-term monthly averages in °C, rounded, for one spot in each surfing region. Individual years swing a degree or two either way, and a week of offshore wind can pull cold water up from below and knock a few more off.

Month Newquay Bournemouth Tenby Tynemouth Thurso
Jan 10 10 9 7 8
Feb 10 9 9 7 8
Mar 9 9 8 7 7
Apr 10 10 10 8 8
May 12 11 11 10 9
Jun 14 13 13 13 11
Jul 16 15 15 15 13
Aug 17 17 16 16 13
Sep 16 17 16 15 13
Oct 15 16 15 13 12
Nov 13 14 13 11 11
Dec 12 12 11 9 10

Source: long-term monthly averages from seatemperature.org.

Three things stand out. Cornwall and the south coast barely drop below 9. The North Sea spends three months at 7. And the far north of Scotland never gets warm enough to matter, which is why the people who surf there look the way they do.

What to wear at each temperature

Rubber is personal. Some people run hot, some people have been cold since 2009. These are the bands most UK surfers settle on after a few bad sessions.

16°C and above

A 3/2 full suit. Late summer in the south-west and south coast. Some people go shorter. They are usually the ones talking about it afterwards.

13–15°C

A good 3/2 or a 4/3. Autumn in the south, midsummer in the north. Boots start to earn their place on a long session or a windy day.

10–12°C

A 4/3 with sealed seams, and boots. A hood if the wind is up. This is Cornwall from November to May and most of the west coast through winter.

8–9°C

A 5/4 hooded suit, 5mm boots and gloves. March in Wales and the south coast. The point where a wetsuit that leaks at the zip stops being annoying and starts being the whole session.

7°C and below

A 5/4 or 6/5 hooded suit, 5–7mm boots, 5mm gloves or mitts. The North Sea and northern Scotland from January to March. Get in and out quickly and do not stand around talking in the line-up.

More on the rubber, and what to layer under it, in What To Wear Surfing In Winter (UK Edition).

Why October is the month to go

October is the best-kept secret in UK surfing, except it is not a secret, it just involves a bit of commitment. The water is still carrying the summer: 15°C in Cornwall and 16°C around Bournemouth, warmer than it will be again until next July. The Atlantic starts sending proper swell. The crowds have gone back to work.

The same water that felt tepid in September now feels warm, because the air has turned. That is the catch: the sea is fine, the car park is not. Which brings us to the part no thermometer measures.

The temperature nobody quotes

Sea temperature decides what you wear in the water. Air temperature and wind decide how the day actually goes. An 11°C sea on a still, bright morning is a good session. An 11°C sea with a 6°C northerly blowing across the car park is a good session followed by fifteen minutes of fumbling with a zip you can no longer feel.

In winter, the cold that gets you is the bit after. Plan for it the way you plan the rubber:

  • Something to stand on. Gravel and wet tarmac take the heat out through your feet faster than the sea did. A changing mat towel solves it.
  • Something on your head, straight away. A fisherman beanie or a Dome Warmer before anything else goes on.
  • A heavy layer you can get into with wet hair. Something like the Core Hood, 420gsm, loose enough to pull on without a fight.
  • Somewhere to change out of the wind. We are building one: the Car Park Robe.

The full routine is in How To Change In A Car Park Without Losing The Will To Live.

Where it is warmest, and where it is not

If you are choosing where to go in winter, the south-west and south coast hold on to a couple of degrees more than anywhere else. The spot guides go into each one:

Or start with the UK Surf Spots guide and the month-by-month UK Surf Season Guide.

The honest bit

A sea temperature is an average of a lot of water. The shallows on an incoming tide in August can feel two degrees warmer than the chart. A river mouth after a week of rain can feel three degrees colder. Use the numbers to pick the suit, then trust your feet in the first thirty seconds.

And if the chart says 7, the wind says northerly and you still go, you are exactly who we make things for.

Kit built for exactly these conditions, not the brochure version. svrf.uk

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