Cool-season grasses — Kentucky bluegrass, tall fescue, perennial ryegrass, and fine fescue — prefer temperatures between 60-75°F. They green up early in spring, grow actively through mild summers, and stay green into late fall. In the northern half of the country, these are the default lawn grasses.
We identified the counties best suited for cool-season grasses using USDA hardiness zones and January temperature data. Counties in zones 6b and colder offer the winter hardiness and cool summers these grasses need.
Best Counties for Cool-Season Grasses
Roseau County, MN in zone 3b with January averages of 2.6°F is ideal for Kentucky bluegrass and fine fescue lawns.
| Rank | County | State | Zone | Jan Avg (°F) | Growing Season |
|---|---|---|---|---|---|
| 1 | Roseau County | MN | 3b | 2.6 | N/A |
| 2 | Cavalier County | ND | 3b | 3.7 | N/A |
| 3 | Kittson County | MN | 3b | 4.5 | N/A |
| 4 | Koochiching County | MN | 3b | 4.6000000000000005 | N/A |
| 5 | Rolette County | ND | 3b | 4.933333333333334 | N/A |
| 6 | Lake of the Woods County | MN | 3b | 5.033333333333333 | N/A |
| 7 | Pennington County | MN | 3b | 5.3 | N/A |
| 8 | Marshall County | MN | 3b | 5.466666666666666 | N/A |
| 9 | Beltrami County | MN | 3b | 5.6 | N/A |
| 10 | Bottineau County | ND | 3b | 5.7 | N/A |
| 11 | Towner County | ND | 3b | 5.8 | N/A |
| 12 | Red Lake County | MN | 3b | 6 | N/A |
| 13 | Pierce County | ND | 3b | 6 | N/A |
| 14 | Clearwater County | MN | 3b | 6.3 | N/A |
| 15 | St. Louis County | MN | 3b | 6.314285714285716 | N/A |
| 16 | Itasca County | MN | 3b | 6.925 | N/A |
| 17 | Hubbard County | MN | 3b | 7.6 | N/A |
| 18 | Lake County | MN | 3b | 10.05 | N/A |
| 19 | Cook County | MN | 3b | 10.08 | N/A |
| 20 | Sheridan County | MT | 3b | 10.319999999999999 | N/A |
| 21 | Daniels County | MT | 3b | 11.1 | N/A |
| 22 | Hill County | MT | 3b | 16.64 | N/A |
| 23 | Phillips County | MT | 3b | 16.9 | N/A |
| 24 | Le Sueur County | MN | 4b | N/A | N/A |
| 25 | Lincoln County | MN | 4b | N/A | N/A |
Recommended Cool-Season Grasses
- Kentucky Bluegrass: The classic lawn grass — dense, dark green, and self-repairing. Best for zones 3-7.
- Tall Fescue: Deep-rooted, drought-tolerant, and shade-friendly. A top choice for transition zones. Zones 4-7.
- Perennial Ryegrass: Fast-germinating and wear-tolerant. Often blended with Kentucky bluegrass. Zones 3-7.
- Fine Fescue: Shade-tolerant and low-maintenance. Perfect for northern lawns with tree cover. Zones 3-7.
Methodology
Counties in USDA hardiness zones 6b and colder are ranked by zone coldness and January average temperature. Data from USDA PHZM 2023 and NOAA climate normals.
Data sourced from USDA Plant Hardiness Zone Map (2023), NOAA National Centers for Environmental Information (1991-2020 Climate Normals), and US Drought Monitor. All figures represent long-term averages and may differ from individual-year observations.