Blagoevgrad is at its most pleasant in late spring (May–June) and early autumn (September–October), when the weather is warm without being oppressive and the university is in session. The student population gives the town much of its energy; during the summer break (late June through August) it quietens noticeably.
Summer (July–August) brings hot weather — temperatures regularly reach 35°C — but Blagoevgrad is a stepping stone to mountain relief: the Pirin and Rila ranges are cooler, and this is the best season for hiking. The Rila Monastery sees its highest visitor numbers in summer.
Winter is mild in the city itself compared to the mountains, though it can be cold and grey. The ski season at Bansko (55 km away) runs from December to April, making Blagoevgrad a less obvious but cheaper base for skiers who prefer a university town to a resort.
Spring and autumn are the sweet spots: pleasant walking weather, the town at full student capacity, and the mountains accessible for hiking before and after the summer high season.