Bulgaria has a temperate-continental climate with moderate features which is characteristic for Central Europe, with hot summers, long, cold winters and very distinct seasons. Abundant snowfalls may occur throughout the country from December to mid-March, especially if you are in the mountainous areas of Bulgaria.
The annual average temperature depends on latitude and ranges from 8°C in the North and 11°C in the South, with temperatures of 2.6°C in the mountains and 12°C in the plains. In general, the warmest areas are in the southern districts of bulgaria, influenced by the nearby mediterranean sea. Daytime temperatures vary from 0-5°C in the winter and 25-30°C in summer months. In the southern areas it can be warmer, in the northern and eastern mountainous districts of Balkan mountains it can be cooler with moderate daytime temperatures and cool nights in the summer and temperatures far below zero in the winter.
Annual average rainfall is about 700 mm, more in the mountains (up to 1000 mm and more) and less on the coast (around 400-600 mm). It can rain throughout the year; in general, winter is the driest season. In summer, showers and thunderstorms are common, especially in the mountains.
Required clothing:
Lightweights are worn in summer on the coast and in low inland areas. Warmer clothes are needed in winter and throughout the year in the uplands. Rainwear is recommended throughout the year.
Koeppen-Geiger classification:
there are two different climate zones in Bulgaria; Most regions have a Cfa Climate, a warm temperated humid Climate with the warmest month above 22°C over average and the coldest month between 18 an -3°C. The climate of the mountainous regions can be classified as Dfb Climate; a humid Snow climate with the warmest month between 10°C and 22°C, the coldest month below -3°C and at last four or more months above 10°C.