Allentown, Pennsylvania – Temperatures dropping to 35 degrees overnight will allow frost to form across the Lehigh Valley and northwest New Jersey, putting outdoor plants at risk between midnight and 8 a.m. Monday.
According to the National Weather Service in Mount Holly, a Frost Advisory is in effect for Sussex, Warren, and Hunterdon counties in New Jersey, along with Northampton, Carbon, Monroe, and Upper Bucks counties in Pennsylvania. The coldest conditions are expected in sheltered valleys, where surface temperatures may briefly dip below 36 degrees between 2 a.m. and sunrise.
Cities including Allentown, Bethlehem, Easton, Stroudsburg, and Flemington will see the greatest risk during the early morning hours. While no travel disruptions are expected on major roads like I-78 or Route 22, the impact will be significant for agriculture and home gardens. Sensitive vegetation, including early-season crops and flowering plants, may be damaged or killed if left unprotected.
Residents should cover or bring in tender plants before midnight. Using cloth coverings or moving potted plants indoors can prevent frost damage. Avoid watering overnight, as wet soil can accelerate heat loss under clear skies.
Conditions will improve quickly after sunrise Monday, but additional cold alerts remain possible if temperatures trend lower in coming nights. Monitor updates from the National Weather Service through early morning.
