MONITORING OF DURATION OF COLD AND WARM SEASONS FOR THE PERIOD 1925-2022 AND ARBORICULTURE IN SAINT PETERSBURG

Abstract

For the period 1925-2022, the earliest date of winter beginning in Saint Petersburg was 11 October 1941, and the latest date was 26 January 2019. The longest winter was in 1941/42 (178 days), and the shortest one - in 2019/20 (14 days). There is a tendency towards an earlier onset of spring, from 3 April (calculated for the period 1925-1934) to 4 March (for the period 2013-2022). The date of beginning of winter in 1986-1995 was the earliest one in the 20th century, with considerable increasing of autumnal period after it, with changing the date of beginning of winter till 19 December (2011-2020). The duration of winter period in 30-years period 1925-1954 comparing with similar period 1992-2022 has shortened from 130 days (36 % of the year) to 105 days (29 % of the year). On prolonging the vegetative period and the period without frosts woody plants have the opportunity to prepare more successfully for wintering. This creates better conditions for their reproductive ability, growth and development. The assortment of trees and shrubs promising for city planting has been enlarging.