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Alberta · climate station 3034596 · 947.0 m

Monarch

Average last spring frostMay 28
Average first fall frostSeptember 10
Frost-free period103 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 8June 3June 1May 26May 24May 22May 17
Fall frost on or beforeAugust 21September 6September 9September 13September 17September 20September 23
Frost-free period ≤ (days)7798101109111115120

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 indoorsApril 2 – April 16
Sow peas, spinach, lettuce and radish outdoors (frost-tolerant)April 30 – May 14
Plant potatoes and onion setsMay 14 – May 28
Transplant tomatoes and peppers; sow beans, corn, squash and cucumbersJune 4 – June 18
Last sowing of quick crops (radish, lettuce, spinach)July 27 – August 11
Harvest or cover frost-tender cropsSeptember 3 – September 10
Plant garlic and spring bulbsSeptember 10 – October 8

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

Lethbridge A · 119 dClaresholm Waterworks · 103 dQueenstown · 122 dGleichen · 103 dBeaver Mines · 90 dHigh River · 86 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 18:57 UTC.
Data Source: Environment and Climate Change Canada Environment and Climate Change Canada Data Servers End-use Licence.

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