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Ontario · climate station 6151689 · 79.2 m

Cobourg Stp

Average last spring frostMay 5
Average first fall frostOctober 10
Frost-free period158 days

1981–2010 normals; ECCC quality code “D” (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 16May 11May 7May 3April 29April 28April 21
Fall frost on or beforeSeptember 22September 28October 1October 6October 12October 16October 27
Frost-free period ≤ (days)133148151157160165175

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 10 – March 24
Sow peas, spinach, lettuce and radish outdoors (frost-tolerant)April 7 – April 21
Plant potatoes and onion setsApril 21 – May 5
Transplant tomatoes and peppers; sow beans, corn, squash and cucumbersMay 12 – May 26
Last sowing of quick crops (radish, lettuce, spinach)August 26 – September 10
Harvest or cover frost-tender cropsOctober 3 – October 10
Plant garlic and spring bulbsOctober 10 – November 7

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

Peterborough A · 132 dBowmanville Mostert · 141 dBurketon Mclaughlin · 155 dJanetville · 121 dOshawa Wpcp · 168 dTrenton A · 158 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 19:10 UTC.
Data Source: Environment and Climate Change Canada Environment and Climate Change Canada Data Servers End-use Licence.

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