When BC lakes lose their ice, region by region

Ice-off is the date most stillwater anglers in British Columbia plan their spring around. The first weeks of open water are a season of their own, and the date they start moves by months depending on where a lake sits. This guide is built entirely from the ice model behind BC Trout Finder: 1,514 lakes, each one run through 65 winters of air temperature on its own coordinate. Every date and every count on this page is computed from that model when the page is built. None of it is typed in, and none of it is an ice report.

What the model is, and what it is not

It is a degree-day model. It reads the daily mean air temperature for the weather grid cell each lake sits in, corrects it to the lake's own elevation, and adds up the cold that builds ice and the warmth that melts it. In the model a lake freezes after five straight days below zero, and its ice goes off once the warmth it has banked has melted the snow lying on the ice and then the ice itself.

It is not an observation. Nobody stood on these lakes to make this page. The model describes what winters have usually done to a lake like this one, not what this winter is doing, and it says nothing at all about whether ice will hold a person. Use these dates to plan a trip. Never use them to decide whether to walk out onto a lake.

Most dates below are medians: first the middle winter of the record for one lake, then the middle lake of a region. A median winter is a typical winter, not a promise. For the typical lake in the model, the middle half of its winters lose their ice inside a window about 19 days wide, so a year that runs a week or two either side of the median is an ordinary year.

The province at a glance

Of the 1,514 lakes the model covers, 1,435 freeze in most winters and carry usual dates. The other 79 are left without them: 53 because the app treats them as too large and deep to freeze over, and 26 because they froze in fewer than half of the winters modelled.

The lakes that stay open lists every one of them and why the model leaves each one open.

Across the lakes that freeze, 5 lakes share the earliest median, 15 January. The latest is Tenquille Lake in the Lower Mainland, at 1,652 m, which holds its ice to a median of 13 July. That is about 6 months between the first lake and the last on one provincial map, and as the section on elevation shows, most of it comes down to how high a lake sits.

Region by region

Lakes that freeze in the model only. Each lake's own median winter, then the middle of the region's lakes.

The coast runs to a different calendar. Vancouver Island's median lake opens on 14 February and the Lower Mainland's on 24 February. The median lake sits at about 209 m on Vancouver Island and 206 m in the Lower Mainland, and spends a median of only 33 days on Vancouver Island and 44 days in the Lower Mainland under ice. The Lower Mainland also carries the widest spread of any region: half its lakes open between 8 February and 27 April, because the same region climbs to lakes like Tenquille Lake, at 1,652 m, whose median ice-off is 13 July.

In the southern interior, lakes in the Kootenays open earliest, at a median of 29 April across 137 lakes. The Thompson-Nicola and the Okanagan follow, both at 15 May. They are also the highest regions in the atlas: the median lake in the Okanagan sits at 1,268 m, and height, as the next section shows, is what holds the ice.

Further north the median lake opens on 3 May in the Cariboo, 10 May in the Omineca, 13 May in the Skeena and 17 May in the Peace. The Skeena is the most uniform region in the model: half its 67 lakes open within 8 days of each other, between 10 May and 18 May.

The median lake freezes first in the Peace, on 31 October, and last on Vancouver Island, on 26 December. Every region page carries the lakes it holds, and every lake page carries that lake's own modelled freeze-up and ice-off window.

Elevation moves the date

Put every lake that freezes on one chart and the pattern is plain. Across 1,434 lakes, each 100 m of elevation pushes the median ice-off about 8 days later. The fit is tight for a province this varied: elevation alone accounts for about 81 percent of the spread in dates between lakes. Some of that is the coast and the interior standing at different heights, but the same pull shows inside a single region.

The widest range of height inside one region is in the Kootenays. The lowest modelled lake there, Rykerts (Vic Mawson) Lake, sits at 539 m and opens at a median of 26 March. The highest, Cerulean Lake, at 2,214 m, opens on 1 July. Same region, 97 days apart.

Each lake's elevation as the model uses it: the height its air temperature is corrected to.

For planning, that makes elevation the first thing to check on a lake page after the region. At the rate above, a lake 300 m higher than its neighbour opens about 23 days later, which is the difference between an early trip and a wasted drive.

The first lakes to open, and the last

Earliest median ice-off

• Dougan LakeVancouver Island, 60 m, 15 January
• Skull LakeVancouver Island, 53 m, 15 January
• Stowell Lake (Lake Stowell)Vancouver Island, 67 m, 15 January
• Toquaht (Toquart) LakeVancouver Island, 67 m, 15 January
• Weston LakeVancouver Island, 62 m, 15 January

Latest median ice-off

• Tenquille LakeLower Mainland, 1,652 m, 13 July
• Semaphore LakeLower Mainland, 1,635 m, 11 July
• Warner LakeThompson-Nicola, 1,844 m, 9 July
• Groundhog LakeCariboo, 1,764 m, 3 July
• Green Timbers LakeLower Mainland, 1,564 m, 2 July

The early list is low water, none of it above 67 m. The late list is high water, none of it below 1,564 m.

How much one winter can differ

The most recent winter the model covers is 2024-25. In it, the median lake lost its ice 13 days earlier than its own median date, across 1,435 lakes. A single winter is one draw from the record, and the record is what the dates on this page describe.

This is the honest limit of a median. A late, cold spring holds the ice past the usual window and a warm one clears it early. The window on each lake page, the middle half of its winters, is the better guide to how far a year can move.

Using these dates

Treat the median as the day to start watching, not the day to go. The ice-off tracker follows what the current winter is doing to each lake in the model, and each lake page carries its own window beside its weather for the week ahead.

The ice-off tracker lists every modelled lake with its usual ice-off and what this winter has done so far.

And one more time, because it matters more than any date here: this is a model of air temperature. It cannot tell you whether ice will hold you, and nothing on this site ever will. Check locally, every time.