Between 1980 and 2021, extreme events related to climate change in EU-27 resulted in an economic loss of EUR 560 billion, of which EUR 56.6 billion from 2021. Climate extremes are becoming more common. Without further action, even greater economic damage is expected in the future. This trend is also noticeable in Slovenia. The difference between the period 1980-2015 and 1980-2021 is as much as € 2,38 billion. In comparison to the previous period 1980-2020, the difference is € 1,01 billion.

Temperature in Slovenia is increasing faster than global average. Increase in the annual average temperature is most evident in the last three decades. Warming of the atmosphere will continue according to the climate change projections. The result of warming is an increase in sea level (due to melting of glaciers and thermal expansion), increase in level of the greenhouse gases in the atmosphere (contributes to warming), and many extreme weather and climate events (like floods, droughts, hail and heavy wind), which will influence the quality of our lives.

The quick rate of retreat of the Triglav Glacier, which began in the second half of the 20^thcentury, further accelerated till the beginning of the 21^st century. Due to increasing intensity of ice thinning, outcropping rocks began to emerge in the middle of the glacier, which disintegrated into two parts in 1992. In the last part of the first decade of the 21^st century, the glacier has been retreating at a slower rate. The last major recession of the glacier was registered after the above average hot summer of 2003.

Annual growing season length is increasing almost everywhere in Europe, mostly in Eastern and Northern part. In Slovenia, the length of the annual growing season is increasing, especially since mid-1990s. According to projections, the duration of the annual growing season throughout Europe will increase in future.

Temperature observations show increasing trend of maximum and minimum absolute temperature in between 1961 and 2022, reflecting a global warming. Number of hot days is increasing, including the frequency of extreme hot days with daily maximum temperature above 35 °C. In the summer of 2013, the highest temperature so far was measured in Slovenia, and local temperature records were observed at many meteorological stations. A record number of hot days was observed in 2022. Number of days with temperature below zero show a decline.

Trends in annual precipitation are not as obvious as temperature trends. Changes between years and differences between regions are significant. According to climate change projections, annual precipitation will slightly increase while changes in seasonal precipitation will be noticeable. The most worrying are summer conditions, because less precipitation and higher temperature might result in higher frequency of droughts. In winter, more precipitation may lead to an increase in flooding events.

Precipitation is highly variable in space and time, even more than temperature (storms and hail). In the last two decades, Slovenia is observing catastrophic droughts and abundant precipitation resulting in floods, sometimes drought and floods occur even within the same year. The maximum snow cover depth and the depth of fresh snow decreased in the period 1961-2022.

Comparison of periods 1961-1990 and 1991-2020 on the chosen representative stations around Slovenia shows decrease of heating degree days by around 10 % and multiple increase of cooling degree days. With projected continuous temperature raise until the end of 21st century, those trends are expected to continue. Thus, in Slovenia, energy demand for cooling will increase in the warmer period of the year, while the energy demand for heating will decrease in colder period of the year. Same trend is projected for Europe in general.

In the last twenty years, occurrences of hydrological droughts of surface waters have become more frequent and intense compared to the previous period, and the variability between individual years has also increased. Very dry and very wet years alternate with intermediate periods of hydrologically normal years. The intensity of droughts during the growing season has become more frequent, although, in the last decade, it has been less intense than in the decade before.

Frequency of groundwater drought is increasing in recent decades in alluvial aquifers. 8 out of 10 years with highest intensity of groundwater drought in period 1981-2023 occurred after year 2000. Groundwater droughts with higher intensity is characteristic for winter while milder groundwater droughts mostly occur at the beginning of autumn. Groundwater drought intensity is also increasing seasonally with time between June and September when groundwater use is pronounced.