Is the Ice Forming?

How much cold has built up on the canals and lakes this freeze — and how far that is from ice the club would call skateable. It never says the ice is safe; only IJsclub Giethoorn, after measuring, can.

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Every hard frost brings people onto Giethoorn's canals — but nobody has measured the ice, and snow ice can look solid while it isn't. This won't tell you the ice is safe. What it does show is how much cold has actually built up on the water this freeze, and how far that is from what the ice club looks for before anyone skates.

Right now

No ice — the water is open.

No cold spell is running. Nothing is forming.

Cold built up

freezing-degree-days this spell

Days freezing

0 days in a row below freezing on average

—

Rough ice estimate

ideal calm, clear, snow-free water

A physics rule of thumb (h ≈ 2.7·√ of the cold built up) for the calmest, clearest, snow-free water. Real ice — on a moving canal, on a wind-stirred lake, and snow ice above all — is thinner and weaker than this. It is not a measurement.

The week ahead

No freeze is in the forecast — the water stays open.

Day	Avg temp	Cold built up
Mon 6 Jul	19°C	0
Tue 7 Jul	18°C	0
Wed 8 Jul	18°C	0
Thu 9 Jul	21°C	0
Fri 10 Jul	22°C	0
Sat 11 Jul	26°C	0

Daily temperatures for Giethoorn, as of 5 Jul, 5:55, from Open-Meteo (CC BY 4.0).

This reads the weather, not the ice

This tool can never tell you the ice is safe. It only estimates how much cold has built up. Ice thickness has to be measured on the spot — snow ice and open water fool the eye, and a canal can be strong in one place and thin a metre away. Only the ice club, after checking, can say a route is open.

Not every water freezes together

Freezes first

The Dorpsgracht and the village canals — Shallow, sheltered and slow-moving, so they skin over first in a cold snap. But they run in the shade of houses and trees and can be strong in one spot and thin a metre on, and the water under the surface never fully stops.

Freezes much later

Bovenwijde, Beulakerwijde and Belterwijde — The big open lakes the Rond de Wiedentocht crosses. Wind keeps them stirred, so they freeze days — often weeks — after the canals, and unevenly, with weak spots over reed beds and channels. A frozen canal says almost nothing about the lakes.

What the ice authorities say it takes

5 cm — KNMI: good, clear 'black' ice can bear one adult at about 4–5 cm — but that is clear ice, not the snow ice that forms here in many freezes.
12 cm — KNSB: an organised tour (toertocht) needs at least 12 cm of good ice over the whole route before it may be skated; 15 cm is held for the Elfstedentocht.

KNMI (ijsdikte en schaatsijs) and KNSB tour-ice guidance · checked Sun 5 Jul

Who actually decides the ice is safe

IJsclub Giethoorn — The village's natural-ice club, going for well over a century. When the ice is reliable it sweeps and marks lanes (banen) and lights the rink at the Molengat on the Kerkweg, and it posts the ice status on its Facebook and X (@ysclubgiethoorn) pages. If a route is open, they are the ones who will have measured it and said so.

Before you step onto any ice

Snow ice looks thick but isn't

White, snowy ice (sneeuwijs) can be twice as thick as clear black ice and far weaker — 4 cm of black ice can hold more than 6 cm of snow ice. In February 2021 the ice master for the Overijsselse Merentocht warned that Giethoorn's ice was 'genuinely dangerous… snow ice, you don't hear it crack' at about 6 cm, while people skated on it anyway.

You skate at your own risk, and there are no marked routes

Unless the ice club has swept and marked lanes, there is no safe route and nobody checking the ice for you. The canals pass under bridges and past gardens where the ice is thinner, and thin ice a step away from thick ice is exactly how people go through.

The lakes are not the canals

A hard-frozen Dorpsgracht does not mean the Wieden lakes are safe. The open water freezes later and unevenly. The long tour ice — Rond de Wiedentocht — needs a sustained, deep freeze that the sheltered canals reach first by a wide margin.

If someone goes through the ice

If someone goes through the ice, call 112 straight away. Don't walk out after them — reach with something long, or throw a rope, from firm ground or the bank. Giethoorn's fire station keeps a quad it uses for ice rescues in the car-free village.

Where the real ice word comes from

IJsclub Giethoorn — The local ice status, swept lanes and the lit rink at the Molengat.
KNSB — schaatsen op natuurijs — The national skating union's natural-ice guidance and the rules organised tours follow.
Nationaal Park Weerribben-Wieden (Natuurmonumenten) — Skating on the park's waters is only allowed once the ice is reliable and always at your own risk; in a freeze the wildlife needs rest, so stay on the open water and off the reed beds.

How this is worked out

Each day below freezing adds to a running total of "freezing-degree-days"; a thaw takes it away, and once a warm spell wipes it out the count starts again. The rough ice estimate applies a standard growth formula to that total for ideal, snow-free water. Daily temperatures come from Open-Meteo. None of it is a measurement of your ice.

Source: KNMI, KNSB and IJsclub Giethoorn; cold-buildup model from Open-Meteo, checked 5 July 2026 (today).