Create your calendar
-3.2°
Slight frost tomorrow morning at 06:00. Frost temperatures between 23:00 – tomorrow 23:00. Bring in or cover sensitive plants
-3.7°
Last 24h: Moderate frost recorded tonight at 03:00. Inspect for frost damage

Growing season

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 10 Apr
Daylight
10+ h
14+ h
10+ h
28 Feb
13 Apr
31 Aug
13 Oct
227 days
Frost-free
10% frost-free
8 May
3 Oct
90% frost risk
148 days
Effective
8 May
3 Oct
148 days

The growing season in Hällaboda is approximately 148 days and is limited by frost.

Last spring frost

The last spring frost normally occurs on 8 May in Hällaboda. At the earliest, the last frost is over around 3 May and at the latest around 18 May.

Frost-free probabilityFrost-free prob. Date Grower's risk level Explanation
10% 3 May High risk Frost 9 out of 10 years after this date
25% 4 May Frost 3 out of 4 years after this date
50% 8 May Normal risk Frost every other year after this date
75% 13 May Frost 1 out of 4 years after this date
90% 18 May Low risk Frost 1 out of 10 years after this date
Growing is often planned around the date when there is a 50% probability that the last spring frost has occurred. In Hällaboda that is 8 May. If you want lower frost risk, choose 75% or 90%, i.e. a later date.

First autumn frost

The first autumn frost normally occurs on 3 Oct in Hällaboda. At the earliest, frost can arrive around 21 Sep and at the latest around 15 Oct.

Frost probabilityFrost prob. Date Grower's risk level Explanation
10% 21 Sep Low risk Frost 1 out of 10 years on or before this date
25% 27 Sep Frost 1 out of 4 years on or before this date
50% 3 Oct Normal risk Frost every other year on or before this date
75% 12 Oct Frost 3 out of 4 years on or before this date
90% 15 Oct High risk Frost 9 out of 10 years on or before this date
Growing is often planned around the date when there is a 50% probability that the first autumn frost has occurred. In Hällaboda that is 3 Oct. If you want lower frost risk, choose 10% or 25%, i.e. an earlier date.

Daylight & Persephone Period

Plants need at least 10 hours of daylight to grow actively. The period with under 10 h is called the Persephone period.

From To Number of days
Daylight over 10 h 28 Feb 13 Oct 227
Persephone period 14 Oct 27 Feb 138
Plan the year's last sowing of cold-hardy plants in Hällaboda so they are approximately 75% mature by 14 Oct when daylight drops below 10 h and growth starts to slow.

Daylight periods

Long-day plants like lettuce, spinach and coriander bolt when daylight gets too long. Plan sowing and harvest during periods when daylight is shorter (10-14 h). Early spring or late summer sowing gives the best results.

Season Light Period Days Advice
Shorter daylight 10-14 h 28 Feb – 12 Apr 44 Grow long-day plants like spinach, lettuce and coriander.
Longer daylight 14+ h 13 Apr – 30 Aug 140 High risk of bolting
Shorter daylight 10-14 h 31 Aug – 13 Oct 44 Grow long-day plants