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 2026-06-12.

• Last spring frost and first fall frost are the mean date of the last spring and first fall frost over the 30-year normal period. They are averages. In roughly half of years, frost falls outside them.
• Frost-free period is the mean number of days between those dates.
• Winter tire windows are computed by the Almanac: monthly mean daily temperature normals anchored at mid-month with linear interpolation across the 7 C threshold. That 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.

Rules and sources

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.

How the guides are written

The Almanac's guides are reference explainers, not opinion posts. Each one is compiled from primary sources: government guidance, municipal reports, and the Almanac's own datasets, with every factual claim linked to its source and the date it was checked. Each guide is reviewed before it publishes, carries a visible last-reviewed date, and is re-checked when a source changes. The aim is a page that is accurate, current, and easy to verify against the source beside the claim.

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. As an Amazon Associate, The Home Almanac earns from qualifying purchases. The full rules are published on the funding page.