site.bta The Weather on September 23
September 23: Sunny, hot in lowlands in afternoon. Lows: 15-20 C in most parts, around 16 C in Sofia. Highs: 32-37 C in most parts, around 33 C in Sofia. Wind southerly, light (up to moderate in East).
Black Sea coast: Highs: 25-27 C. Wind southeasterly, light to moderate. Seawater temperature: 23-25 C.
Mountains: Wind south-southwesterly, moderate. Highs: around 27 C at 1,200 m, around 20 C at 2,000 m.
Source: National Institute of Meteorology and Hydrology