Quebec Hardiness Zones — Zone by City & Region

Quebec spans a wide range of plant hardiness zones — from roughly Zone 1 in the far north (Nunavik, the Ungava coast) to Zone 5b in the warmest southwest, the Montreal and Montérégie lowlands. The great majority of Quebecers garden in Zone 4b to Zone 5b along the St. Lawrence valley: Montreal is Zone 5b, Gatineau (the Outaouais) is Zone 5a, and Quebec City, Sherbrooke, and Trois-Rivières are Zone 4b. Farther from the river the zone drops — Saguenay–Lac-Saint-Jean and Bas-Saint-Laurent run Zone 3–4a, and the far north falls to Zone 1–2. Zones are assigned by Natural Resources Canada based on winter minimum temperature plus summer heat, rainfall, snow cover, wind, and frost-free days — so a Canadian zone is not identical to the U.S. (USDA) zone of the same number. Check your exact location on the NRCan Plant Hardiness Zone Map at planthardiness.gc.ca.

Montreal is Zone 5b — the warmest zone in Quebec. The Island of Montreal's urban heat island pushes sheltered downtown and near-river pockets toward Zone 6a, while low-lying rural sites off-island can run a sub-zone colder. Montreal's average last spring frost is around May 10 and first fall frost around October 10, giving a frost-free growing season of roughly 150–160 days — Quebec's longest. For perennial and shrub selection use the zone (5b); for vegetable transplant timing use the frost dates. This makes Montreal Quebec's best bet for borderline-hardy plants and longer-season warm crops.

The warmest hardiness zone in Quebec is Zone 5b, in the extreme southwest — the Island of Montreal, the Montérégie (the farmland south and east of Montreal), and the St. Lawrence lowlands upstream toward the Ontario border. Sheltered, urban-heat-island pockets on the Island of Montreal edge into Zone 6a. This corner has Quebec's earliest last frost (early May), its longest growing season, and enough summer heat for warm-season crops that struggle farther downriver. It is warmer than anywhere in the province north or east of it, where the zone steps down toward the Laurentians, the Appalachians, and the north.

Northern Quebec is far colder than the populous St. Lawrence valley. Saguenay–Lac-Saint-Jean and Bas-Saint-Laurent sit around Zone 3–4a, Abitibi-Témiscamingue around Zone 2b–3b, and the Côte-Nord, Nord-du-Québec, and Nunavik drop to Zone 1 or lower. Because these regions aren't in our city dataset, don't take a single number as gospel — look up your exact town on the Natural Resources Canada Plant Hardiness Zone Map at planthardiness.gc.ca, which maps every location in the country. Northern Quebec gardeners lean on short-season varieties, season-extension (row covers, cold frames, Wall-O-Water), and cold-hardy perennials rated to Zone 3 or below.

Three ways, most precise first: (1) Use the official Natural Resources Canada Plant Hardiness Zone Map at planthardiness.gc.ca — enter your address or postal code for a location-specific zone that accounts for local terrain. (2) Use our interactive Zone Finder (growersguide.ca/zone-finder) — click Quebec to see zones and frost dates for cities across the province. (3) Match to the nearest city in the table on this page. Remember that zones can shift by one or two sub-zones within a single area: the St. Lawrence riverbank and dense urban cores run warmer, while inland, higher-elevation, and low-lying frost-pocket sites run colder. When a plant tag says 'hardy to Zone 5,' choosing one rated a zone colder than yours is the safe hedge.

No — and this trips up Quebec gardeners who buy plants or read growing advice from U.S. sources. The USDA system is based on winter minimum temperature alone. Natural Resources Canada's system factors in seven variables — winter minimum, summer maximum, frost-free period, rainfall, snow cover, and wind — so a Canadian 'Zone 5' is defined differently from a USDA 'Zone 5,' even though the numbers look the same. NRCan does also publish a separate USDA-method map for cross-border comparison. Practical rule for Quebec: use the Canadian (NRCan) zone from planthardiness.gc.ca for Canadian-sourced plants and seed catalogues, and treat a U.S. plant tag's zone as a rough guide only — when in doubt, pick the hardier (lower-numbered) option.

Your hardiness zone tells you which perennials, shrubs, and trees will survive a typical Quebec winter; your frost dates tell you when to plant tender vegetables. In Zone 5b (Montreal, Montérégie) you can grow most perennials sold in Quebec garden centres, plus borderline Zone 6 plants in sheltered urban spots. In Zone 4b (Quebec City, Sherbrooke, Trois-Rivières) stick to Zone 4-or-hardier perennials and expect a last frost around mid-to-late May. In the Zone 3–4a regions farther north and east, choose Zone 3 perennials (hardy roses, lilacs, most native shrubs) and lean on season-extension for warm-season vegetables. For crop timing, see our Quebec city planting guides linked below and our frost calculator.

Yes — microclimates routinely move a site one to two sub-zones off the regional headline zone. The three big drivers in Quebec are the St. Lawrence River (the valley and its lowlands run milder than the highlands on either side — the river is why Montreal, Trois-Rivières, and Quebec City are warmer than the Laurentians just north), elevation (the Laurentian and Appalachian uplands are colder and frostier than the valley floor), and the urban heat island (dense city cores like Montreal hold winter warmth, while low-lying rural frost pockets just outside the city can be a full zone colder). This is why a location-specific NRCan map lookup beats relying on a single regional number.

Quebec City is Zone 4b. Sitting downstream on the St. Lawrence where the valley narrows and cools, it runs about a sub-zone colder than Montreal (5b), with a shorter season: an average last spring frost around mid-to-late May and a first fall frost near the start of October. Choose Zone 4-or-hardier (ideally Zone 3) perennials, shrubs, and trees. Sheltered, urban sites near the river hold a little more warmth than the exposed plateau and the Laurentian foothills just north of the city.

Gatineau is Zone 5a. As the Quebec side of the national-capital region in the Outaouais, it shares Ottawa's continental climate — cold, snowy winters and warm summers — and is one of the milder parts of Quebec after the Montreal area. The average last spring frost is around mid-May. Choose Zone 5-or-hardier perennials; low-lying and rural pockets in the Outaouais can drop to Zone 4b, so hedge toward hardier plants away from the urban core.

Sherbrooke is Zone 4b — the hub of the Estrie (Eastern Townships), a region of rolling Appalachian hills southeast of Montreal. Its elevation and inland position give it a shorter, cooler season than the Montreal lowlands, with a mid-to-late-May last frost. Pick Zone 4-or-hardier perennials, shrubs, and trees, and expect valley-bottom and hilltop sites around the Townships to differ by a sub-zone from the city reading.