Day 10: Prompting only
Canada's clocks on 10 November 2026, nine days after British Columbia, Alberta, the Northwest Territories and Manitoba kept their summer time. 28.8% of Canadians did not fall back.
On 1 November 2026, 10,659,405 Canadians did not turn their clocks back. This year British Columbia moved to UTC−7 all year, Alberta and the Northwest Territories to UTC−6, and Manitoba to UTC−5, and the time zone database starts all four on that night. Magenta is the 28.8% of Canadians who stopped changing their clocks this year. Blue is the 3.4% who already kept one time all year: Saskatchewan, Yukon, northeastern British Columbia, Creston, Atikokan, Southampton Island and Blanc-Sablon. Grey is the 67.8% who still fall back and spring forward.
Switch to 10 Nov 2026 and 10 Nov 2025 to see the clocks themselves, with one step of blue for each offset from UTC. The West moved an hour east. Last November Canada's clocks spanned four and a half hours, from UTC−8 in Vancouver to UTC−3:30 in St. John's. This November no one in Canada is on UTC−8: British Columbia keeps Yukon's time, Alberta keeps Saskatchewan's, and Manitoba keeps Ontario's and Quebec's. 65.1% of Canadians now share one winter clock, from Winnipeg to the Gaspé and Iqaluit.
New lines open where the old ones closed. The database records no change for Nunavut, so its Cambridge Bay zone in the west fell back to UTC−7, an hour behind the Northwest Territories, and its zone from Rankin Inlet to Resolute fell back to UTC−6, an hour behind Manitoba. The United States changed nothing, so the border is a time line until spring: Osoyoos, British Columbia is an hour ahead of Oroville, Washington, Coutts, Alberta an hour ahead of Sweet Grass, Montana, and Emerson, Manitoba an hour ahead of Pembina, North Dakota.
Click anywhere in Canada: the page asks unmap's time zone API about that point and shows its zone, the time there now, and its offsets on the three days the map compares.
How it's made
The prompts that made this map, word for word.
The theme is Prompting only: make a map from start to finish in a chat window or on a command line. This one was made in Claude Code from the prompts above. The slash command loads a standing brief for the challenge: the steps, the house style and the checks every day must pass. Claude proposed the maps, wrote the script and ran it, and found the 2026 changes when the API's answer for Vancouver did not match last year's rules; the time zone database's release notes confirmed them. The script asked unmap's time zone API 165,383 questions. It lays a grid over Canada, asks the zone at each corner on land and at one point inside each of the 5,161 municipalities, and splits a cell in four wherever the answers disagree, down to cells about 900 m across. Each of the 23 zones it found was then asked its offset on 10 November 2025, 10 November 2026 and 1 July 2026, and zones that give the same three answers share a colour. The boundaries are timezone-boundary-builder's, drawn from OpenStreetMap, and the rules are the IANA Time Zone Database, both release 2026f. The database starts each change on 1 November 2026, though British Columbia's law took effect on 9 March and Alberta's on 18 June. It records the law, not local habit: a town that keeps a neighbour's time by custom shows its official zone. Shares of Canadians count each municipality whole, in the zone at one point inside it, with its 2021 census population.
Data
- Time zones: unmap time zone API, on the IANA Time Zone Database 2026f (public domain) and timezone-boundary-builder 2026f boundaries, © OpenStreetMap contributors (ODbL).
- Municipalities and population: Statistics Canada, 2021 Census, census subdivision cartographic boundary file and Geographic Attribute File, as on Day 9. Used under the Statistics Canada Open Licence.
- Basemap: unmap, © OpenStreetMap contributors.
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