Hungary has four distinct seasons. Summer is the most popular time to visit but also the most crowded and expensive; spring and autumn are often a better choice.
Spring (April–May) is lovely — mild temperatures, blooming countryside, and fewer crowds than summer. The Budapest Spring Festival in late March brings concerts, opera, and arts events to the capital. May is arguably the best month: warm enough to sit outside, quiet enough to get into restaurants without a reservation.
Summer (June–August) is peak season. Budapest is busy and can feel hot and humid. Lake Balaton fills with Hungarian holidaymakers and European tourists. The big draw is the Sziget Festival in August, one of Europe's largest music festivals, held on an island in the Danube. The Street of Hungarian Flavours food festival runs around August 20 (Hungary's national holiday, St. Stephen's Day), with stalls and open-air celebrations across the country.
Autumn (September–October) is excellent for wine tourism. The Tokaj harvest festival happens in October, and Eger's Bull's Blood Festival celebrates the famous red wine of the region. The weather stays warm well into September, prices drop, and Budapest's ruin bars are at their atmospheric best.
Winter (December–February) is cold, sometimes bitterly so. The upside is that Budapest's Christmas markets — at Vörösmarty Square and around St. Stephen's Basilica — are among the best in Central Europe. Thermal baths become genuinely appealing rather than just touristy in winter. January and February are quiet and cheap.