Data and methodology

An almanac is only as good as its sources. Here is exactly where every number comes from, how each date is computed, and how the data stays current without a human babysitting it.

Climate data

All climate figures derive from the Canadian Climate Normals published by Environment and Climate Change Canada (ECCC), accessed through the MSC GeoMet open data API. The Almanac currently computes from 655 stations holding complete monthly temperature normals, 638 of which also publish frost observations. Data last fetched 2026-06-11.

• Last spring frost and first fall frost are ECCC normal elements 13 and 14: the mean date of the last spring and first fall frost over the normal period. They are averages. In roughly half of years, frost falls outside them.
• Frost-free period is ECCC normal element 21: mean days between those dates.
• Winter tire windows are computed by the Almanac: Winter tire windows derived from monthly mean daily temperature normals anchored at mid-month with linear interpolation across the 7 C threshold. The 7 C threshold follows Transport Canada and tire industry guidance on winter compound performance.

When you set a place, the Almanac uses your nearest station by straight-line distance. Microclimates are real: a valley floor or lakeshore can run a week or more off its station's record.

Provincial rules and deadlines

Every law, deadline, and entitlement cited on this site links to the responsible government source beside the claim, with the date we last verified it. Winter tire law from provincial transport ministries and insurers' regulators; moving rules from each province's health ministry, licensing agency, and registry.

The refresh pipeline

Reference sites die of staleness. The Almanac's data is refreshed by scheduled pipelines, not by memory:

• Climate normals re-fetch on a schedule and whenever ECCC publishes a new normals release.
• Rule pages are re-checked automatically; when a source page changes, a human is alerted the same day and the entry is re-verified before the change ships.
• Every dataset carries its last verified date in the open. If something looks stale, it says so.

What this site is not

General reference, carefully built, but not legal, financial, insurance, or safety advice. Laws change mid-year, leases and policies have their own terms, and frost ignores averages. For decisions with real consequences, confirm against the linked primary source.

Independence and revenue

The Home Almanac is independently built and Canadian. Some pages may carry clearly marked affiliate links or quote forms. They never influence the dates, rules, or recommendations shown, and the site works identically if you ignore them.