SWO winter climate normals — Waterloo and London design temperatures for diesel operability
Confidence: Verified against Environment Canada 1981–2010 Climate Normals.
Why this matters
Winter-grade Type B diesel covers the SWO January monthly mean (~−12 °C) but not extreme-minimum nights without operability additives or Type A. The climate numbers below are the operational reason fleets carry anti-gel additives as a second line of defence, and the reason yards in unheated locations are exposed during a polar-vortex event.
Stations
| Station | Climate ID | Elevation | Jan daily mean min | Extreme minimum |
|---|---|---|---|---|
| Waterloo Wellington A | 6149387 | 317 m | −12.1 °C | −31.5 °C |
| London CYXU | (London Int'l Airport) | — | −10.7 °C | −31.7 °C |
Kitchener-Waterloo averages 64 frosty days per year; the region sees lows in the minus-twenties on roughly six nights per year, most often in January.
CFPP margin question
Type B winter diesel at CFPP −20 °C covers the January monthly mean but does not cover an extreme-minimum night. Operators with unheated outdoor yards through a polar-vortex event need either:
- A treated blend with cold-flow improver (CFPP often pulled to −30 °C or lower), or
- Type A winter diesel, or
- Anti-gel additive dosed at delivery (typical SWO operator practice — see
op-winter-diesel-blending).
Use on marketing pages
These figures support the winter-diesel article in the Resources section. On the marketing-page side, the takeaway is operational rather than numeric: "the coldest nights in Waterloo and London are colder than the standard winter blend was designed for, which is why we treat our deliveries past Halloween." Don't put extreme-minimum °C figures on a sector landing page — they belong in the article body or the source-attribution footer.
Sources & structured attribution
- source.document: Environment and Climate Change Canada — Canadian Climate Normals 1981–2010, Waterloo Wellington A (Climate ID 6149387) and London CYXU; summary at Current Results (currentresults.com/Weather/Canada/Ontario)
- source.captured_date: 2026-05-16
- source.confidence: verified
- concept_category: climate / winter operability
- applies_to_services: winter diesel additive program; clear and dyed diesel delivery November–March
- applies_to_audiences: SWO fleet, agriculture, construction; copywriters editing winter-diesel pages or any seasonal-supply messaging