Spring (March–May) is the best time to visit Ajlun. The forest is intensely green, wildflowers cover the hillsides, and temperatures are comfortable for hiking — warm in the afternoons, cool in the evenings. The RSCN trails are at their most beautiful.
Summer (June–August) is hot but more bearable than lowland Jordan because of the altitude — Ajlun sits at around 1,000 metres. Weekends bring Jordanian families escaping Amman's heat, so the castle and nature reserve can get busy on Fridays and Saturdays. Midweek visits are quieter.
Autumn (October–November) is olive harvest season, which adds texture to a visit: the countryside is active, roadside stalls sell fresh olive oil, and the light is golden. Winter brings cold and occasional snow — the forest looks dramatic but some trails become muddy. The castle is open year-round.