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Ontario · climate station 6155878 · 83.8 m

Oshawa Wpcp

Average last spring frostApril 29
Average first fall frostOctober 14
Frost-free period168 days

1981–2010 normals; ECCC quality code “A” (A = WMO “3 and 5 rule”; B ≥ 25 years; C ≥ 20 years; D ≥ 15 years of data). An average is not a guarantee: a late frost is still possible.

Probabilities

10%25%33%50%66%75%90%
Spring frost (0 °C or lower) on or afterMay 14May 7May 5April 29April 24April 23April 15
Fall frost on or beforeOctober 5October 8October 10October 14October 17October 20October 25
Frost-free period ≤ (days)150160161166174177185

Example: the spring 10% column is the date after which a frost occurs in only one year in ten.

Indicative planting calendar

Start tomatoes, peppers and eggplant indoorsMarch 4 – March 18
Sow peas, spinach, lettuce and radish outdoors (frost-tolerant)April 1 – April 15
Plant potatoes and onion setsApril 15 – April 29
Transplant tomatoes and peppers; sow beans, corn, squash and cucumbersMay 6 – May 20
Last sowing of quick crops (radish, lettuce, spinach)August 30 – September 14
Harvest or cover frost-tender cropsOctober 7 – October 14
Plant garlic and spring bulbsOctober 14 – November 11

General gardening rules of thumb computed from this station's average last/first frost dates; they are not ECCC data. Adjust to local conditions and seed-packet instructions.

Nearby stations

Burketon Mclaughlin · 155 dBowmanville Mostert · 141 dToronto Buttonville A · 157 dJanetville · 121 dLindsay Frost · 143 dRichmond Hill · 157 d
Sources & licences

Environment and Climate Change Canada — Canadian Climate Normals 1981–2010 (station data, MSC Datamart) (30-year averages; not updated). Retrieved 2026-10-18 19:11 UTC.
Data Source: Environment and Climate Change Canada Environment and Climate Change Canada Data Servers End-use Licence.

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