site.btaSummer 2025 Among the Driest and Hottest Summers in Bulgaria Since Mid-20th Century

The summer of 2025 is one of the driest and hottest summers in Bulgaria since the mid-20th century, the National Institute of Meteorology and Hydrology (NIMH) said on Monday.

The summer of 2025 had average seasonal temperatures above the norm, with a deviation of between 0.5C and 3C. It was less hot than the hottest summer in the last 13 years, in 2024, but it was still one of the hottest summers in Bulgaria since 1950. The summer of 2025 was also one of the driest summers in Bulgaria since 1950, similar to the summers of 2000 and 2012. Seasonal precipitation totals were below the climate norm, ranging from 7 to 74% of the norm.

The summer of 2025 was characterized by prolonged heat waves, numerous large field and forest fires, short-lived severe storms with hail and local flooding due to intense rainfall.

In June, more than five consecutive days with maximum air temperatures above 32C (heatwave) were recorded in various parts of the country. The longest heatwave was in the Petrich and Sandanski areas (Southwestern Bulgaria).

In June, the development of agricultural crops proceeded at an accelerated pace, with above-normal temperatures. During the second and third ten-day periods, extremely high temperatures were recorded, which had an adverse effect on plant growth and development. Below-average rainfall and high water consumption by plants during the period led to intensive depletion of soil moisture reserves. This resulted in widespread extreme soil and atmospheric drought.

In July, the dry and hot weather jeopardized the survival of some of the spring crops grown under non-irrigated conditions. As a result of below-normal rainfall at the end of the month, productive soil moisture reserves were completely depleted in many of the country's agricultural areas.

In the first half of August, the deepening summer drought and extremely high temperatures compromised the corn and sunflower harvest in many parts of the country. Sunflower yields were unusually low, in some places below 100 kilogrammes per decare, and a significant proportion of corn crops grown under non-irrigated conditions will not be harvested.

The rainfall at the end of the second and third ten-day periods of August was unevenly distributed and too late for late crops grown under non-irrigated conditions. The rainfall at the end of August mainly moistened the upper soil layer and improved the conditions for deep plowing and pre-sowing treatment of the areas intended for sowing autumn crops. At the end of the month, there was no productive moisture in the 50 and 100 centimetres of topsoil. 

Due to the above-average summer temperatures, the early white wine grape varieties reached technological maturity much earlier than usual.

During most of the summer season, river levels in Bulgaria remained largely unchanged or declined. As a result of rainfall on certain days, short-term increases were recorded, which were more significant during the periods June 27-30 and August 4-6. During the three summer months, water levels in all rivers were below monthly norms. During the last ten days of July, the Lebnitsa River, in the area of the hydrometric station near the village of Lebnitsa, dried up. From the last ten days of July and throughout August, the Fakiyska River, in the area of the hydrometric station near the village of Zidarovo, and the Ropotamo River, in the area of the hydrometric station near the village of Veselie, also dried up.