Western Pennsylvania stretches across USDA planting zones 5b through 7a, with the coldest temperatures ranging from -15 to -10 degrees.
It’s important to know your zone because each zone represents climatic conditions that can support different plants. Knowing your zone helps you create a yard full of thriving and beautiful plants and grass.
Overview of Western Pennsylvania planting zones
Western Pennsylvania is primarily in zones 6a and 6b. Some of Western Pennsylvania is in zone 5b, with an even smaller portion in zone 7a. The growing season lasts an average of 173 days. It is shorter than Southern Pennsylvania’s growing season, but longer than the Northeast area and about the same as Central Pennsylvania.
Visit our guide, How to Use the Plant Hardiness Zone Map in Your Yard, to learn how it can help you build and maintain a healthy and thriving landscape.
Zone 5b
Counties in this zone experience the coldest winters, with average lows between -15 and -10 degrees. Most of McKean County is in zone 5b. The next county with the greatest surface area primarily covered by zone 5b is Elk County. Parts of Warren, Forest, and Somerset Counties are also in this zone.
Zone 6a
This zone has temperatures ranging between -10 to -5 degrees. The climate consists of warm and humid summers and cold and snowy winters. The majority of Western Pennsylvania is in this zone.
Most of Erie, Crawford, Venango, Cambria, Butler, Lawrence, Forest, and Somerset Counties are in zone 6a. Zone 6a also dominates Mercer, Clarion, Jefferson, and Clearfield counties. The lower part of Elk County and sections of Warren County are in this zone.
Zone 6b
Cities in this area experience average lows between -5 and 0 degrees. Zone 6b is the next largest planting zone in Western Pennsylvania. It covers most of the central to southwestern region of Western Pennsylvania.
The zone includes sections in all the counties on the western border of the state, comprising a larger area of the counties more central and southern, like Armstrong, Washington, and Greene Counties. Zone 6b covers all of Allegheny and Beaver counties and most of Blair and Bedford Counties. Some of the more popular cities in this zone include Altoona, Johnstown, New Castle, and Murrysville.
Zone 7a
This area is warmer than the rest of the western region, with extreme temperatures ranging from 0 to 5 degrees Fahrenheit. Zone 7a is the smallest one in Western Pennsylvania, covering the upper northwestern border of Erie County and small segments in Allegheny, Beaver, and Bedford counties.
Check out these articles for more about lawn care and landscaping in Pennsylvania:
- When to Aerate Your Lawn in Pennsylvania
- When to Dethatch Your Lawn in Pennsylvania
- When to Stop Mowing Your Lawn in Pennsylvania
Trust the pros
If you don’t want to spend your free time planting, pruning, watering, mowing, fertilizing, and generally breaking your back in the yard, Lawn Love’s pros do that and more. We have qualified lawn care and landscaping pros in Pittsburgh, Erie, Altoona, and Johnstown.
Main Photo Credit: Cbaile19 | Wikimedia Commons
