Safe to Plant

Halifax, Nova Scotia, Canada

Frost dates for Halifax

The full distribution rather than a single date. Every figure below is a percentile of 30 years of daily minimum temperatures at this location, expressed as the date it fell on.

Median last spring frost

23 April

Half of years are later than this. Not a planting date.

Median first autumn frost

13 November

The far end of the outdoor season.

Frost-free season

204 days

Between those two dates in a median year.

Last and first frost by severity

Read a row as: in this fraction of years, the last frost of spring had already happened by this date. The 90% column is the cautious planting date; the 10% column is the gamble.

Light frost — nights at or below 0°C (32°F). Air temperature reaches freezing. Kills basil, beans and unhardened tomatoes; hardy crops shrug it off.
Frost 1 year in 10 Median 9 years in 10 Earliest Latest
Last of spring 16 Apr 23 Apr 1 May 9 Apr 10 May
First of autumn 5 Nov 13 Nov 29 Nov 2 Nov 3 Dec
Frost-free days 227 204 188 every year on record saw this
Moderate frost — nights at or below -2.2°C (28°F). Damages half-hardy plants and most blossom. This is the threshold that decides a fruit crop.
Frost 1 year in 10 Median 9 years in 10 Earliest Latest
Last of spring 25 Mar 7 Apr 17 Apr 20 Mar 26 Apr
First of autumn 13 Nov 25 Nov 7 Dec 5 Nov 10 Dec
Frost-free days 258 232 210 every year on record saw this
Hard frost — nights at or below -4.4°C (24.1°F). Ground freezes and even hardy crops check their growth. Effectively the end of the outdoor year.
Frost 1 year in 10 Median 9 years in 10 Earliest Latest
Last of spring 5 Mar 21 Mar 2 Apr 3 Mar 17 Apr
First of autumn 29 Nov 9 Dec 23 Dec 8 Nov 30 Dec
Frost-free days 293 263 240 every year on record saw this

Dates in the southern hemisphere are computed on a growing year that starts in July, which is why "last of spring" falls where it should rather than in the middle of the calendar.

Chance of frost, week by week

Jan Mar Apr Jul Sep Oct Dec
Chance of at least one air frost during each week of the year, measured across the full record. The flat stretch in the middle is your frost-free season.

Temperature through the year

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Mean monthly temperature across the record. Months shown in blue average at least one air frost.

Monthly means and average number of frost nights.
Month Mean low Mean high Frost nights
January -5.8°C 0.4°C 27.7
February -5.8°C 0.3°C 25.7
March -2.9°C 2.8°C 25.7
April 0.9°C 7°C 10.9
May 5.2°C 11.8°C 0.1
June 10.4°C 16.5°C 0
July 14.8°C 20.5°C 0
August 15.6°C 21.3°C 0
September 13°C 18.9°C 0
October 8.2°C 13.8°C 0
November 3°C 8.2°C 6.9
December -2°C 3.5°C 21

Turn these dates into a planting calendar →