Kaluga Region has a moderate continental climate, with sharp seasonal differentiation: moderately warm and humid summers and moderately cold winters with settled snow covering, transitional between a more humid climate of western regions of European Russia and a drier and more continental climate of its eastern regions. The average annual air temperature is +3.5° to +4.5°C, average annual precipitation - 600−700 mm. In humid years, precipitation may reach 1,000 mm or more, and in dry years can be less than 400 mm. Most precipitation comes in the form of rain, and a smaller share in the form of snow. Maximum precipitation is reached during the summer months, and minimal – during the winter months.
The average length of winter is around 95 days. The coldest month is January. Its average temperature throughout the region’s districts ranges from -9.0° to -10.5°C.
The prevailing winter winds are south-west. One of the specific features of winter in the region is frequent thaws. During three winter months (December-February) there are on average 17-18 days, — when the average daily temperature rises above 0°C. During these thaws daytime temperature can reach +6 to +7°C. The length of the thaws, however, rarely exceeds 2-3 consecutive days.
Spring in the region does not usually take up its entire assigned three-month calendar period (March-May). March should be classified as a pre-spring period, as it is characterized by many processes that are specific for winter.
The beginning and end of the summer period is usually associated with average daily temperature crossing the +15°C mark. Within this limit, summer includes almost the entire month of June, July and most of August.
Autumn is characterized by the increasing strength of winds. Recurring warm periods during autumn, known as Indian summer, are associated with movement of warm air anticyclones from the South. The second half of autumn is damp, windy and cold, with extended periods of drizzling rain.