Toronto Climatic Design Data for Building Projects

Direct answer

For a Toronto project, verify the exact site against the 2024 Ontario Building Code before using a climatic row. The NBC 2020 City Hall excerpt is useful for orientation, but Etobicoke, North York and Scarborough have separate rows and a different site or future-climate brief may require different inputs.

Toronto has multiple climatic rows

The phrase "Toronto design temperature" hides an important location choice. NBC 2020 Table C-2 has a Toronto Metropolitan Region group with separate entries for Etobicoke, North York, Scarborough and Toronto (City Hall). The City Hall row is at 90 m (295 ft); the other listed locations have different elevations and winter values.

That means a downtown reference cannot be carried to every project merely because the postal address says Toronto. At project start, retain the exact address, coordinates and elevation, then record the selected climatic row and why it is accepted. For an unlisted or atypical site, obtain direction under the governing Ontario Code rather than averaging nearby rows.

Small excerpt, explicit statistical basis

The official NBC 2020 publication lists the following selected City Hall values.

The conversions above are arithmetic, not a second official source. Do not relabel the January figures as annual ASHRAE percentiles, and do not use July dry- and wet-bulb entries as though they were necessarily coincident unless the governing method says so.

Ontario edition and City requirements are separate checks

Ontario Regulation 163/24 adopts NBC 2020 together with Ontario amendments as the province's building code. Ontario's Building Code page points users to the current 2024 Code Compendium and its filing date. A project record should state the precise compendium/amendment used and the permit transition, not only "OBC 2024."

City planning or green-building requirements can add another layer. The Toronto Green Standard, development approvals and owner requirements may demand modelling or resilience work beyond the minimum building code. Establish which requirements apply to the project type and approval path; they do not change the provenance of an Appendix C code value.

Use the values to frame, not finish, design

The winter values justify early attention to continuity of insulation, glazing performance, air leakage, thermal bridges and heat-recovery frost strategy. The summer dry- and wet-bulb values show that sensible cooling and moisture control both need an explicit services basis. The 3,520 °C-day heating index places Toronto in a heating-dominated context, but it does not answer overheating, solar gain or future cooling risk by itself.

At concept stage, compare at least three separate models or checks:

1. the code-compliance basis using the adopted Ontario climatic values;
2. the required typical-year hourly file for energy use and comfort; and
3. a future-service-life scenario for overheating, cooling capacity and enclosure durability.

ClimateData.ca's future building design value guidance uses Toronto City Hall as a cooling example and explains how historical and future 2.5% July values can be compared. Since NBC 2025 now includes projected climatic data in the national model, state whether a future value comes from an adopted legal provision or a supplemental resilience study.

Information that still belongs in the consultant brief

This page does not select the final HVAC design percentile, CWEC station, wind pressure, snow load, rainfall intensity, flood elevation or future warming level. Each has a different use and governing source. The architect's job is to keep those inputs visible and traceable until the responsible consultant and AHJ confirm them.

Toronto climate basis card

The populated values below are a deliberately small excerpt of the NBC 2020 Toronto (City Hall) row. IP conversions are calculated from the published SI values and rounded to one decimal where needed. They are an orientation and audit aid, not a substitute for the current Ontario Code or project consultant's basis.

Stop rule: Toronto's metropolitan rows are not identical. Do not use the City Hall excerpt for a suburban or elevated site until the location choice and governing Ontario table are confirmed.

Related

• Canadian Climatic Design Data and the National Building Code
• Vancouver Climatic Design Data for Building Projects
• Calgary Climatic Design Data for Building Projects

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Source & method: Selected Toronto (City Hall) fields from National Building Code of Canada 2020, Appendix C, Table C-2, first printing, checked against the official NRC publication; Ontario Regulation 163/24 and Ontario's current Building Code page for adoption and update status; ClimateData.ca's federal-partner guidance for future design values. Sources: https://nrc-publications.canada.ca/eng/view/object/?id=515340b5-f4e0-4798-be69-692e4ec423e8 ; https://www.ontario.ca/laws/regulation/240163 ; https://www.ontario.ca/page/ontarios-building-code ; https://climatedata.ca/resource/introducing-future-building-design-values-choosing-and-using-future-climatic-design-data/ . Verify against the current Ontario Code compendium and AHJ; only selected temperature/HDD fields are excerpted, not the protected table as a whole.