What Weather to Expect in December

The average monthly temperature across the country is expected to be 1-2 degrees above normal, with precipitation amounts lower than usual. Weather conditions throughout the month will primarily be dry and warmer than average, according to the Hydrometeorology and Monitoring Center.

In December, the sun's altitude continues to decrease in the northern hemisphere, leading to shorter daylight hours. The duration of sunshine during the month is expected to reach 110-120 hours. The major atmospheric circulation in the country will predominantly be influenced by cold air flows penetrating from northern latitudes. Severe frosts are especially observed when the incoming cold air originates from regions of Arctic Siberia or Scandinavia.

The average monthly temperature in the Republic during December is projected to be -3.9°C. In high mountainous areas above 2000 meters above sea level, the monthly average temperatures are notably lower, ranging from -6 to -11°C. January is typically the coldest month of winter; however, in 18-20% of winters, December has recorded the coldest temperatures. Typically, the lowest temperatures in December are observed in the last ten days of the month, although in some instances, as was the case in 1984 in the northeastern regions, they were recorded in the first ten days.

The coldest Decembers were noted in 1953, 1970, 1982, 1984, 1987, and 2002, when the average monthly temperatures were 6-8 degrees below normal. The historical minimum temperature recorded in December in the Republic was observed in 1948 in Ashotzk, where nighttime temperatures dropped to -40°C.

December 2002 stood out for its severely low temperatures, with the average temperature gradually dropping in the second half of the month, reaching record lows by December 28. The lowest temperature in the Ararat Plain was recorded at -32°C, while in Yerevan, it was -28°C, exceeding historical minimum values.

Warmer Decembers were recorded in 1938, 1940, 1966, 1980, 1981, 1998, and 2008, during which the maximum temperatures in the Ararat Plain and Yerevan reached +21 to +22°C, while in the lowland areas of Tavush and Syunik, they reached +24 to +26°C.

The relative humidity in December is expected to be quite high, at 70% and above. The average amount of precipitation is projected to be 38mm, with the least amount of precipitation observed in the lowland areas of the Ararat Plain and southeastern regions, reaching up to 20mm. In the lakeside areas of Lake Sevan, it reaches 20-25mm, in the foothills, 30mm, in mountainous regions, 60mm, and in high mountainous areas, 80-90mm.

The wettest Decembers in the Republic were in 1946, 1956, 1958, 1969, 1987, and 2003, when precipitation amounts reached 200-300% of the monthly norm; the driest Decembers were noted in 1911, 1947, 1961, 1980, 1995, 1999, and 2004, when no precipitation was recorded in the valleys of the Republic.

Precipitation mainly falls as snow, with the snow cover in mountainous areas reaching 20-30cm, while in the Republic's warmer regions, a stable snow cover does not establish during the first and second decades of December. Calm weather predominantly prevails, with high wind speeds observed in the mountains and mountain passes, reaching up to 18-20m/s, and gusts up to 25m/s.

December is characterized by frequent fogs, especially in the Ararat Plain, Syunik, and Shirak. The Decembers of 2013 and 2016 were particularly cold and foggy in the Ararat Plain and Yerevan, attributed to the stagnation of cold air in the Ararat Plain. The fog of December 2016 persisted until the first decade of March 2017.

Winter solstice occurs on December 21, marking the longest night and shortest day of the year in the northern hemisphere, after which daylight duration begins to gradually increase.