site.btaThe Weather in September

The average monthly temperatures this September in Bulgaria are expected to be above the normal range, which for most of the country is between 17C and 20C, and for the mountains - between 3C and 10C. The highest temperatures in September will be between 32C and 37C and the lowest between 7C and 12C, higher on the Black Sea coast, Anastasia Kirilova, a forecaster at the National Institute of Meteorology and Hydrology (NIMH), said on Thursday, presenting the weather forecast for September.

The monthly rainfall in September will be around the usual level, which for the plains is between 40 and 60 litres per square metre, and for the mountain and mountainous areas - 60 to 80 litres per square metre.

Most of the first ten days will be mostly sunny across most of the country, and temperatures will be higher than usual. There is a greater chance of cumulus and cumulonimbus clouds and showers in the eastern areas during the first few days, and more around the middle of the period in more places across the country.

During the second 10-day period, the outlook is for more days with an increased chance of precipitation. Temperatures will decrease relatively but remain above normal. It is expected to be dry and sunny in the early and last days of the period.

Temperatures are also expected to remain relatively high during the third 10-day period. The weather will be mainly sunny, with temporary cloud increases mainly in the afternoon and in mountainous areas. There is a greater chance of more cloudy conditions and precipitation in more places across the country during the first half of the of the last 10-day period of September.

The intensity of the atmospheric circulation over Europe weakens in September due to a reduction in the heat differences between the ocean and land. This is causing an intensification of climatic drought in Bulgaria. Although infrequent in some years, rainfall exceeds monthly norms several times. 

Typically, there are two to six cloudy days in September and about four days with rain. Extremely high temperatures of around 40C have also been measured during the month, but the second half of September has frost conditions in the high fields.

On September 22 at 15 hours and 43 minutes, the autumnal equinox occurs and astronomical autumn begins, Kirilova noted.