Climate
The climate of Moscow Oblast is humid continental, with clearly expressed seasonality – short but warm summers and long, cold winters; the continentality increases from northwest to southeast. The period of the average temperature below 0 °C (32 °F) lasts 130–150 days, beginning in early or mid-November and ending in late March (or very early April). The average annual temperature varies from +3.5 °C (38.3 °F) to +5.5 °C (41.9 °F). The coldest months are January and February with the average temperature of −9 °C (16 °F) in the west and −12 °C (10 °F) in the east. With the arrival of arctic air, the temperature drops to below −20 °C (−4 °F) that may last up to twenty days during the winter, with the temperatures reaching −45 °C (−49 °F). The minimum temperature of −54 °C (−65 °F) was observed in Naro-Fominsk. Thaws often occur in December and February due to the Atlantic, and rarely the Mediterranean cyclones. The thaws usually last several days, and their total number from November to March can reach fifty. Snow starts accumulating in November, though sometimes in late October or early December, and disappears in mid-April (sometimes in late March). The snow depth is 25–50 centimeters (9.8–19.7 in) and the soil freezes to 65–75 centimeters (26–30 in). The warmest month is July with the average temperature of +18.0 °C (64.4 °F) in the northwest and +20.0 °C (68.0 °F) in the southeast. The maximum temperature of +40 °C (104 °F) was recorded in Kolomna during 2010 Northern Hemisphere summer heat waves. The average annual rainfall is 450–650 millimeters (18–26 in), the precipitation is maximal in the northwestern and minimal in the southeastern regions. The summer precipitation is usually 75 millimeters (3.0 in), but severe droughts occur once in 25–30 years, with less than 5 millimeters (0.20 in) of rain over June–August.