Methodology

How a number gets on the page

Checked 14 November 2026. A fact is a sentence plus a URL plus a date. The date is the day we read the source, not the day the climate period ended.

URL scheme

One place, one URL. A country is /mexico/. A city is /mexico/cancun/. The same pattern is used for Canada, the United Kingdom, and Italy. Months stay in the table. They do not get twelve extra URLs.

Climate

Mexico uses Servicio Meteorológico Nacional normals for 1991–2020, issued 6 November 2026, one station file per place. Canada uses Environment and Climate Change Canada's 1991–2020 composite normals. The United Kingdom uses Met Office 1991–2020 location averages, except that the UK sheet is the HadUK-Grid national block printed on that page, not Heathrow. Italy uses the WMO 1991–2020 normals distributed by NOAA NCEI. Where a month is blank in the file, the cell is blank.

We do not name a best month. The page restates the highest high, the lowest low, and the heaviest and lightest water-column months, and leaves the choice to the reader.

The other facts

Plugs and voltage are the IEC world-plugs country lines. Driving is a statute or a government page, quoted in our own sentences. Tipping is a tourism office or, in Mexico, the consumer-protection agency, and only when that page states a practice. Tap water is whatever CDC's traveler page actually says, which in these four countries is not a yes or a no. Currency names and codes are ISO 4217, maintained by SIX. Time zone names are IANA's, matched to the Mexican time-zone law where a city had to be placed in a zone. Entry requirements are a link, not a matrix.

Left off on purpose

• Toronto (City) rainfall is blank for April through October, so the sheet prints precipitation instead.
• Vancouver Harbour has no rainfall element. The sheet prints precipitation and does not borrow the airport.
• No tipping percentage for Toronto, Vancouver, Banff, or for Canada as a whole. Mexico's page says tipping is voluntary because that is what Profeco wrote, not a percent.
• Venice Tessera's March average high is blank in the WMO file.
• Roma Ciampino is missing summer precipitation, so Rome uses Fiumicino.
• Puerto Vallarta station 14116 has no 1991–2020 normal. The sheet uses El Cuale.
• Ringway, the old Manchester Airport station, closed in 2004. The sheet uses Woodford.
• The full list, including a Tacubaya file that disagrees with an older WMO copy, is in the repository file GAPS.md.