The climate of the Lycoming valley is favorably influenced by the lower elevation of the area compared to the surrounding terrain. Since the prevailing winds reach the area from the southwest to the north, there is a slight moderating effect on winter extremes of cold.
Radiation cooling on clear nights is somewhat more frequent than in adjacent areas.
Deep valley fogs occasionally persist until nearly midday. Cold air drainage from the surrounding hills is experienced during several nights but the cool temperatures are often modified by the proximity of the river and adjacent damp areas. The winters are milder than those experienced to the west and cold spells are frequently interrupted by incursions of warmer coastal weather. In summer the air frequently becomes trapped in the valley and higher temperatures and humidities result, generally benefitting the local agriculture. The long irregular range south of the river forms an effective barrier to free air movement.