Mercer County, New Jersey
Local growing conditions for Mercer County: the USDA hardiness zones found here, frost dates, and live weather for communities across the county. Based on 22 ZIP codes in our data.
Hardiness zones in Mercer County
Mercer County spans these USDA plant hardiness zones (by number of ZIP codes):
Local weather & frost dates
Open any community in Mercer County for its live forecast, frost dates, and planting calendar:
Yardley 08628
Hightstown 08520
Hopewell 08525
Pennington 08534
Princeton 08540
Princeton 08542
Princeton 08544
Princeton Junction 08550
Titusville 08560
Windsor 08561
Trenton 08608
Trenton 08609
White Horse 08610
White Horse 08611
Trenton 08618
Mercerville 08619
Groveville 08620
Trenton 08629
The College of New Jersey 08638
Lawrenceville 08648
Hamilton Square 08690
Robbinsville Center 08691
More for New Jersey
- Agriculture in New Jersey
- Frost dates across New Jersey
- USDA hardiness zones explained
- Planting calendar by ZIP code
County growing conditions are compiled from our ZIP-code database, USDA hardiness-zone data, and NOAA climate normals. Conditions vary within a county by elevation and local microclimate. Page updated Aug 4, 2026.