Last Frost Date Ajax — April 22 (Zone 6b)
Last frost date Ajax: April 22 for the central core (Zone 6b). Lakeshore neighbourhoods benefit from Lake Ontario moderation; north Ajax (Salem, Audley) runs slightly later.
Last frost date Ajax 2026: April 22 (Zone 6b). Lakeshore: April 18–21. Pickering Village, Westney Heights (central): April 20–25. Salem, Audley (north): April 25–30. Wait until May 1–10 to transplant tomatoes. Source: Environment and Climate Change Canada (1991–2020).
Ajax Neighbourhoods
| Area | Last Frost |
|---|---|
| Lakeshore Ajax (Waterfront Trail, Bayly south) | April 18–21 |
| Pickering Beach Road area | April 18–21 |
| Pickering Village (south-central historic) | April 20–23 |
| Westney Heights (central) | April 22–25 |
| Central Ajax / Bayly Street central | April 22–25 |
| Salem (north) | April 25–28 |
| Audley, Carruthers Creek upper (northeast) | April 25–30 |
Ajax can drop to -3°C in late April. A 2.4×9m frost blanket protects an entire raised bed.
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Frequently Asked Questions
What is the last frost date in Ajax?
Ajax's last spring frost date is April 22 for the central core — Zone 6b. This is the historical 50th-percentile average from Environment and Climate Change Canada climate normals (1991–2020). Lakeshore Ajax neighbourhoods (Waterfront Trail area, Bayly Street south, Pickering Beach Road) run 3–4 days earlier (April 18–21) thanks to Lake Ontario moderation. North Ajax (Salem, Audley, Carruthers Creek upper area) runs 3–5 days later (April 25–30) because of greater distance from Lake Ontario. The full historical range spans April 10 (earliest) to May 10 (latest).
When can I plant tomatoes in Ajax?
Wait until May 1–10 to transplant tomatoes, peppers, basil, beans, and squash in Ajax. North Ajax (Salem, Audley) should wait until May 5–15. Cool-season crops can be direct sown from late March. Victoria Day weekend (third Monday of May) is the GTA's traditional safe-transplant deadline. Ajax's growing season is approximately 190 days, supporting reliable cultivation of full-season vegetables including indeterminate tomatoes, peppers, sweet corn, and winter squash.
What is the last frost date in Pickering Village, Westney Heights, Salem, and Audley?
Ajax neighbourhoods vary by distance from Lake Ontario. Lakeshore Ajax (Waterfront Trail, Bayly south, Pickering Beach): April 18–21. Pickering Village (south-central historic area): April 20–23. Westney Heights (central): April 22–25. Central Ajax / Bayly Street central: April 22–25. Riverside, Northwest Ajax: April 23–26. Salem (north): April 25–28. Audley (northeast): April 25–30. Carruthers Creek upper area: April 25–30. Rural northern Ajax: April 28–May 5.
What growing zone is Ajax?
Ajax is officially Zone 6b for the central and southern parts under the Canadian Plant Hardiness Zone system. Lakeshore neighbourhoods sit in the warmer end of Zone 6b. North Ajax drops to the cooler end of Zone 6b approaching Zone 6a in elevated rural areas. A Zone 6 plant overwinters reliably anywhere in Ajax; Zone 7 plants survive most years in lakeshore spots but die in severe polar-vortex winters. Ajax shares similar climate with Pickering, Whitby, and the rest of Durham Region's lakeshore communities.
How do I protect plants from late frost in Ajax?
Late frost in Ajax can drop to -3°C in worst cases. Floating row cover (Reemay, Agribon) over transplants protects to about -3°C and is the GTA standard. Cloches or inverted pots over individual seedlings. Heavy mulch around transplants. Plant tender crops in the warmest spot — south-facing fence, lakeshore-side garden, against a heat-radiating brick wall. Don't transplant tender crops if nights below 3°C are forecast through May 10. Available at Sheridan Nurseries Pickering, Plant World Pickering, Home Depot Ajax, Canadian Tire.
How does Ajax's last frost compare to other Durham Region cities?
Ajax's April 22 last frost matches Pickering and is similar to other Durham Region lakeshore cities (Whitby, Oshawa). Compared to GTA cities: 2 days later than Toronto and Mississauga (April 20), 1 day earlier than Hamilton (April 23), 4 days earlier than Vaughan (April 26), 6 days earlier than Markham and Brampton (April 28), 17 days earlier than Guelph (May 7). Ajax's 190-day growing season matches most of the GTA lakeshore and supports reliable harvests of every common vegetable plus tender perennials in lakeshore microclimates.
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