What is the last frost date in Richmond Hill?

Richmond Hill's last spring frost date is April 28 for the central core — Zone 6b. This is the historical 50th-percentile average from Environment and Climate Change Canada climate normals (1991–2020). South Richmond Hill (Mill Pond area, Lake Wilcox south, Yonge/Highway 7 corridor) runs 2–3 days earlier (April 25–28). North Richmond Hill on the Oak Ridges Moraine (Oak Ridges, Jefferson, north Bayview) runs 3–5 days later (May 1–5) because the moraine sits at significantly higher elevation (300 m vs 200 m for south Richmond Hill). The full historical range spans April 12 (earliest) to May 12 (latest).

When can I plant tomatoes in Richmond Hill?

Wait until May 5–15 to transplant tomatoes, peppers, basil, beans, and squash in central and south Richmond Hill. Oak Ridges Moraine neighbourhoods (Oak Ridges, Jefferson, north Bayview Hill) should wait until May 10–20 due to elevation. Cool-season crops (lettuce, peas, brassicas) can be direct sown from late March. Victoria Day weekend (third Monday of May) is the safe-transplant deadline across the GTA. The growing season is approximately 180 days in central Richmond Hill and 170 days on the Oak Ridges Moraine.

What is the last frost date in Oak Ridges, Bayview Hill, Jefferson, and Mill Pond?

Richmond Hill neighbourhoods vary by elevation and position on the Oak Ridges Moraine. Mill Pond (south, central core): April 25–28. Yonge/Highway 7 corridor: April 26–29. Bayview Hill (south): April 26–29. Lake Wilcox area: April 27–30. Central Bayview / Bayview Glen: April 28–May 1. Jefferson (Oak Ridges Moraine): May 1–5. Oak Ridges (north on moraine): May 2–6. North Bayview Hill: May 1–5. The Oak Ridges Moraine elevation effect adds roughly 5–7 days to last-frost dates compared to lower-elevation south Richmond Hill.

What hardiness zone is Richmond Hill?

Richmond Hill is officially Zone 6b for the central and south parts under the Canadian Plant Hardiness Zone system. The Oak Ridges Moraine portion (north Richmond Hill) sits in the cooler end of Zone 6b approaching Zone 6a at higher elevations. Rural areas immediately north of Richmond Hill (King City, Aurora) are Zone 6a. A Zone 6 plant will reliably overwinter anywhere in Richmond Hill; Zone 7 plants survive most years in south Richmond Hill protected spots but die in severe polar-vortex winters.

How does the Oak Ridges Moraine affect Richmond Hill's climate?

The Oak Ridges Moraine is a 160 km long ridge of glacial sediment running east-west across the GTA, rising to about 300 m elevation through north Richmond Hill, Oak Ridges, and Jefferson neighbourhoods. The elevation difference vs central Richmond Hill (~200 m) translates to roughly 2–3°C cooler night temperatures in spring, producing 5–7 days of later last-frost dates and slightly later autumn first frost. Oak Ridges and Jefferson essentially have a different microclimate than south Richmond Hill despite being only 5–7 km apart. The moraine also produces more reliable snow cover in winter, which protects perennial plants from polar-vortex temperature extremes.

How do I protect plants from late frost in Richmond Hill?

Late frost in Richmond Hill can drop to -3°C in worst cases. Floating row cover (Reemay, Agribon) over transplants protects to about -3°C. Cloches or inverted pots over individual seedlings. Heavy mulch around transplants. Plant tender crops in the warmest spot — south-facing fence, against a heat-radiating brick wall. Don't transplant tender crops if nights below 3°C are forecast through May 12. Available at Sheridan Nurseries Richmond Hill, Plant World, Home Depot, Canadian Tire.

RICHMOND HILL FROST DATE 2026

Last Frost Date Richmond Hill — April 28 (Zone 6b)

Last frost date Richmond Hill: April 28 for the central core (Zone 6b). South Richmond Hill (Mill Pond, Bayview Hill) earlier; Oak Ridges Moraine neighbourhoods (Oak Ridges, Jefferson, north Bayview) 3–5 days later.

Last frost date Richmond Hill 2026: April 28 (Zone 6b). Mill Pond, south Bayview Hill: April 25–28. Oak Ridges, Jefferson (moraine): May 1–5. Wait until May 5–15 to transplant tomatoes; May 10–20 on Oak Ridges Moraine. Source: Environment and Climate Change Canada (1991–2020).

Richmond Hill Neighbourhoods

Area	Last Frost
Mill Pond (south, central core)	April 25–28
Yonge/Highway 7 corridor	April 26–29
Bayview Hill (south)	April 26–29
Lake Wilcox	April 27–30
Central Bayview / Bayview Glen	April 28–May 1
Jefferson (Oak Ridges Moraine)	May 1–5
Oak Ridges (north on moraine)	May 2–6

Recommended

Frost Blanket / Row Cover

Richmond Hill can drop to -3°C in late April. Oak Ridges Moraine areas are colder. A 2.4×9m frost blanket protects an entire raised bed.

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More Last Frost Date Guides

❄️ Vaughan — April 26 → ❄️ Markham — April 28 → ❄️ Toronto — April 20 → 🍁 All Canadian frost dates →

Last Frost Date Richmond Hill — April 28 (Zone 6b)

Richmond Hill Neighbourhoods

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