From Longman Dictionary of Contemporary Englishopen-airˌopen-ˈair adjective [usually before noun] OUT/OUTSIDEhappening or existing outdoors SYN outdoor open-air concerts an open-air swimming pool
Examples from the Corpus
open-air• Indoor pools exist, and Moscow boasts a year-round, heated open-air affair between the Kremlin and the Defence Ministry.• We had lunch at an open-air cafe in the city square.• In summer there are open-air concerts and theatre performances in the park.• The Mayrhofen Brass Band gives regular open-air concerts in fine weather.• There's a big open-air market there on Saturdays.• an open-air market• Marchers were due to congregate at Market Square for an open-air meeting.• Six miles away, at the open-air Minack Theatre, plays are performed with the sea as a backdrop.• Opera fans come from all over the country to see open-air performances in a unique setting.• There is a small cosy bar with open-air tables.• From here it appears to be not the central generating plant of ministerial power but some vast open-air theatre. 