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Northwest Territories · climate station 2202101 · 169.2 m

Fort Simpson A

Average last spring frostMay 26
Average first fall frostSeptember 1
Frost-free period97 days

1981–2010 normals; ECCC quality code “C” (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 afterJune 17June 8May 31May 27May 24May 21May 15
Fall frost on or beforeAugust 7August 17August 21August 26September 2September 8September 14
Frost-free period ≤ (days)5875809198104115

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 31 – April 14
Sow peas, spinach, lettuce and radish outdoors (frost-tolerant)April 28 – May 12
Plant potatoes and onion setsMay 12 – May 26
Transplant tomatoes and peppers; sow beans, corn, squash and cucumbersJune 2 – June 16
Last sowing of quick crops (radish, lettuce, spinach)July 18 – August 2
Harvest or cover frost-tender cropsAugust 25 – September 1
Plant garlic and spring bulbsSeptember 1 – September 29

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

Fort Liard A · 121 dHay River A · 101 dYellowknife A · 115 dNorman Wells A · 106 dFort Smith A · 87 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 19:08 UTC.
Data Source: Environment and Climate Change Canada Environment and Climate Change Canada Data Servers End-use Licence.

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