December is a popular month to ask about Knokke-Heist because conditions can shift week to week along this coast. Expect the water near 9.0°C, with daily variation from wind, tides and recent storms. We refresh the live value from Open-Meteo Marine every hour, so the headline above always reflects the current state of the North Sea.
Knokke-Heist sea temperature in December — averages 9.0°C
The sea at Knokke-Heist in Belgium averages 9.0°C during December, based on long-run climatology for the North Sea. Use the live reading below for today's actual water and the monthly grid to compare with the rest of the year.
Average sea · December
9.0°C
cold · Poor
Live water now
…
Recommended wetsuit
5/4mm fullsuit + boots & gloves
At 9.0°C you need a 5/4mm fullsuit with boots, gloves and ideally a hood.
Monthly comparison
Cold — wetsuit recommended · Knokke-Heist
Can you swim at Knokke-Heist in July? — 18.0°C water18.0°CCan you swim at Knokke-Heist in August? — 19.0°C water19.0°CCan you swim at Knokke-Heist in September? — 17.0°C water17.0°CCan you swim at Knokke-Heist in October? — 14.0°C water14.0°CCan you swim at Knokke-Heist in November? — 11.0°C water11.0°CCan you swim at Knokke-Heist in December? — 9.0°C water9.0°C
Frequently asked questions
What is the average sea temperature at Knokke-Heist in December?
Knokke-Heist averages 9.0°C in December, based on long-run climatology for the North Sea.
Is the sea warm enough to swim at Knokke-Heist in December?
Not without thermal protection — a wetsuit is recommended at 9.0°C.
Do I need a wetsuit at Knokke-Heist in December?
A 4/3 mm full wetsuit, boots and neoprene cap are recommended.