The climate of Polistovsky Reserve is moderately continental. It is formed under the influence of the Atlantic, continental and Arctic air masses in high cyclonicity. The monthly average air temperature here is: in January - 8.1°C in July + 17.2°C. The annual amount of precipitation with amendments of a precipitation gauge is 685 mm. The calm in the Reserve does not exceed 5 days per year while the rest days are windy. In general, western and south-eastern winds are slightly dominating; the rarest are northern, eastern and north-eastern winds. In winter, winds are more southern and south-west; in summer winds have western and south-western directions. The average speed of winds is 2-6 m/s.
Frequency of winds (%%)
North East South West
7* 7 14 19
North-East South-East South-West North-West
7 18 16 12
*- percent of the number of windy days; calm in the Reserve - 5 days per year.
|Winter (mid November - March) in Polistovsky Reserve is moderately soft, dominated by cloudy weather with frequent (5-9 days per month) thaws. Thaws are often accompanied by black ice. The prevailing daily temperature in the coldest months (December - February) is -5 - -7°C, at night -8 - -10°C (absolute min. -41°C). Precipitation falls in the form of snow. The snow cover is set in early December; its average height is 20-30 cm (max. 60 cm). A winter month may have 5-10 days with drifting snow. Fogs can occur throughout the winter in morning hours (from 5 to 15 days with fog per month). The number of cloudy days is 10 to 28 per month (maximum in December); there may be 2 to 6 clear days in the month.|
|Spring (April - May) in Polistovsky Reserve is cool in the beginning of the season, and moderately warm in the end. Precipitation falls in the form of rain. Snow cover disappears in the end of March (completely in mid-April). The spring thaw in the Polistovsky Reserve begins in early April and lasts 20-30 days.|
|Summer (June - August) of Polistovsky Reserve is moderately humid (summer falls make about 40% of the annual precipitation). The prevailing daytime temperature is 18-20°C (absolute max. 35°C), at night 13-15°C. Precipitation in the form of short showers (12-17 days with rain per month), often with storm (9-12 days with storm per month). The number of clear days per month is about 10, rarely up to 19. Fogs can occur at night and morning (5-8 days with fog per month).|
|Autumn (September - mid-November) in Polistovsky Reserve is moderately warm in the early season, cool in October - November. Precipitation in the form of protracted drizzling rain, in November, often in the form of wet snow. The weather is usually cloudy with long fogs (12-14 days with fog per month). Winds usually have southern and south-western directions in the winter and western and south-western in the summer. The average wind speed is 6.2 m/s.|
once per year - to 16-20 m/s
once per 5 years - to 19-23 m/s
in average - 23 days per year,
average time - 1.7 hours
in average - 1.9 days per year,
maximum - 6 days per year
Raised bogs of Polistovsky Reserve create microclimatic conditions that differ from other landscapes. First of all, abundance of moisture causes high humidity in the warm season. Effects of solar radiation on bogs are different from other natural landscapes of the North-West Russia. Raised bogs are characteristic of the soil direct heated by sunlight, and in case of poor thermal conductivity of peat - overheated. Raised bogs have a powerfully developed moss cover insulating the lower layers of peat from the heating; this is the reason why the temperature of the root layer is always 2 - 4˚C higher than the corresponding depth of the mineral soil. The surface temperature of the swamp may be 30 - 40˚C, which is higher than the air temperature. Poor thermal conductivity of peat causes night frosts on swamps. In the spring the ice under the moss thaws slowly and remains there until the end of May. Study of the depth of freezing and thawing of various sections of Polistovsky Reserve bogs showed some microclimatic differences. The highest depth of freezing belongs to fuscum complexes (29.0 cm) covered with oppressed pine and ridges of a ridge-hollow complex (25.5 cm), as well as formed Shagnum fuscum. At the same time, the maximum depth of freezing of sedge-moss crop-sphagnum associations was 23.3 cm, and for hollows of ridge-hollow complexes this value made 23.0 cm.