The climate of Ukraine

The climate of Ukraine is largely temperate. The south shore, which lies on the Crimea, has a warmer Mediterranean climate. Rainfall is unevenly distributed, generally being higher in the north and west of the country due to the influence of the Carpathian Mountains. There are regular snowfalls between October and April and winter temperatures range between -8°C and 2°C, dependent on location, with lower temperatures inland away from the moderating effect of the Black Sea. Extremely cold spells can occur when easterly winds blow in from Siberia, which can drop the temperatures to as low as -20°C to -30°C. Summers are generally warm, becoming hot in the south, with temperatures ranging from 18°C to 27°C (3).

Air temperature changes until now

Heat wave and cold wave changes until now

In the Carpathian Region (encompassing Croatia, Hungary, Slovakia, Czech Republic, Poland, Ukraine, Romania and Serbia), heat wave events have become more frequent, longer, more severe and intense over the period 1961 - 2010, in particular in summer in the Hungarian Plain and in Southern Romania (7). Cold wave frequency, average duration, severity, and intensity over this period, on the other hand, generally decreased in every season except autumn. In this study, a heat wave was defined as at least five consecutive days with daily maximum temperature above the long-term 90th percentile of daily maximum temperatures. Similarly, a cold wave was defined as at least five consecutive days with daily minimum temperatures below the long-term 10th percentile of daily minimum temperatures (7). The trend analysis shows a general tendency to more frequent, longer, more severe and more intense heat wave events in every season in the entire Carpathian Region. On the other hand, the cold waves show a general tendency to less frequent, shorter, less severe, and less intense events (7). 

The Carpathian Region and the Mediterranean area are the two European hotspots showing a drought frequency, duration, and severity increase in the past decades and in particular from 1990 onwards (8). When drought effects are exacerbated by heat waves or vice versa, such combination may cause devastating effects, as it happened in summer 2003 in Central Europe (9). 

During 1951-2011, most of the heat wave episodes in Ukraine occurred at stations located in Eastern Ukraine (in this case heat waves being defined as periods of more than 5 consecutive days with daily maximum air temperature ≥5 °C above the mean daily maximum air temperature during June to August for the normal climatic period 1961–1990). The number of heat wave episodes was highest for almost all stations in the decade 2001–2010. For many stations, the longest heat wave duration occurred in the first two decades of August 2010, i.e. in the period of the extremely severe heat wave in Western Russia (6).

Air temperature changes in the 21st century

According to calculations based on a regional climate model and two different emission scenarios, wintertime average daily temperatures in the period 2071–2100 are simulated to increase with respect to the period 1961–1990 from 3°C to more than 7ºC in east Europe and Russia depending on which emission scenario and which driving global model is used (1). The warming in the cold end of the temperature distribution is even larger. The strongest warming occurs on cold days.

Little research has been conducted into how the climate in Ukraine specifically will change over the course of the 21st century. Most research has concentrated on the larger area of Northern Europe, which includes Ukraine. Projected changes for the period 2080-2099, relative to 1980-1999, for Northern Europe (from multi-model simulations using the medium-high emissions scenario) are summarized in the Table below (4).

Season             Range of projected temperature change (°C) Range of projected precipitation change (%) Dec to Feb +2.6 to +8.2 +9 to +25 Mar to May +2.1 to +5.3 0 to +21 Jun to Aug +1.4 to +5.0 -21 to +16 Sep to Nov +1.9 to +5.4 -5 to +13 Annual +2.3 to +5.3 0 to +16

The strong increase in wintertime temperature in east Europe and Russia is probably connected to the reduction of the snow cover in the scenario runs. The mechanisms involved are feedback processes involving temperature, snow cover and albedo. With decreasing snow cover the albedo becomes lower. The lower albedo implies that more shortwave radiation is absorbed in the ground which in turn leads to higher surface temperatures. The largest reduction of the length of the snow season is calculated to be in a zone reaching from central Scandinavia through southern Finland and the Baltic countries and further towards the southeast into Russia (2).

Owing to the projected increase in warm extremes in the future Ukraine may experience an increase in summer dry periods by the late 21st century (3).

Precipitation changes in the 21st century

The largest increases in rainfall are projected for winter in northern and central Europe, including the Ukraine, (see Table above) although less is projected to be in the form of snow. Fewer days of snow and frost, along with shorter frost seasons and a widening of frost-free areas are projected throughout northern Europe over the coming century. One multi-model study suggests that by 2100 the Ukraine may see approximately a 60 day reduction in the number of days with frost cover, and a 50 day reduction in days with snow cover in the northern part of the country by 2100, relative to the 1961 to 1990 average. The study also found that changes in snow cover in northern and central Europe, including Ukraine, correlated well with increases in winter maximum temperatures; an increase of 1°C corresponding roughly to a decrease of 10-15% of days with snow cover (5).

References

The references below are cited in full in a separate map 'References'. Please click here if you are looking for the full references for Ukraine.

1. Räisänen et al. (2003), in: Kjellström (2004)
2. Kjellström (2004)
3. Met Office Hadley Centre (2010)
4. Christenson et al. (2007), in: Met Office Hadley Centre (2010)
5. Jylhä et al. (2008), in: Met Office Hadley Centre (2010)
6. Shevchenko et al. (2014)
7. Spinoni et al. (2015)
8. Spinoni et al. (2013), in: Spinoni et al. (2015)
9. Fink et al. (2004); Ciais et al. (2005), both in: Spinoni et al. (2015)