Festal adj. Of a celebration or festival.
Mid August may be the most festive time in North America
because it's the most likely time to schedule an outdoor festival in good weather.
Amiable, Ameliorative, Amused, Amusing, Ascendant, Auspicious, Beatific, Blissful, Blythe, Blithesome, Boisterous, Bonzer, Brilliant, Buoyant, Carefree, Celebratory, Cheerful, Cheery, Childlike, Chuffed, Chipper, Cock-a-hoop, Cohortative, Coltish, Confelicitous, Content, Contented, Couthie, Crackerjack, Dapatical, Delightful, Delighted, Diverted, Droll, Easygoing, Effulgent, Elated, Enjoyable, Eudaemonistic, Euphoric, Excelsior, Exhilarated, Exuberant, Fain, Fantastic, Festive, Frabjous, Free, Frolicsome, Fulgent, Fun, Gelastic, Gelogenic, Glad, Gleeful, Good, Good-humoured, Good-natured, Grateful, Gratified, Happy, Happy-go-lucky, Harmonic/Harmonious, Heartsome, Humorous, Hunky-dory, In a good mood, In good spirits, Insouciant, Jiggish, Jocose, Jocoserious, Jocular, Jolif, Jolly, Jovial, Joyful, Joyous, Jubilant, Lepid, Liefly, Light, Light-hearted, Lively, Ludibund, Ludic, Lusory, Mabsoot, Merry, Mirthful, Optimistic, Overjoyed, Panglossian, Peppy, Perky, Playful, Pleasant, Pleased, Positive, Profulgent, Radiant, Rejuvenated, Rejuvenescent, Relaxed, Reviviscent, Rhapsodic, Risible, Rollicking, Sanguine, Satisfied, Shining, Slamin', Sportive, Sprightly, Sunny, Supercalifragilisticexpialidocious, Thrilled, Thrilling, Tickled, Twitterpated, Uber, Upbeat, Upbuilding, Uplifted, Uplifting, Vegete, Vibrant, Vitative, Vivacious, Waggish, Weleful, Welsome, Whimsical, Wonderful, Zoetic