Central Plains

ZONE 1. Coldest Winters in the West and Western Prairie States
Growing season: early June through Aug., but with some variation ¬ the longest seasons are usually found near this zone's large bodies of water. Frost can come any night of the year. Winters are snowy and intensely cold, due to latitude, elevation, and/or influence of continental air mass. There's some summer rainfall.

ZONE 2. Second-coldest Western Climate
Growing season: early May through Sept. Winters are cold (lows run from -3 degrees to -34 degrees F/-19 degrees to -37 degrees C), but less so than in Zone 1. In northern and interior areas, lower elevations fall into Zone 2, higher areas into Zone 1.

ZONE 10. High Desert Areas of Arizona, New Mexico, West Texas, Oklahoma Panhandle, and Southwest Kansas
Growing season: April to early Nov. Chilly (even snow-dusted) weather rules from late Nov. through Feb., with lows from 31 degrees to 24 degrees F/-1 degree to -4 degrees C. Rain comes in summer as well as in the cooler seasons.

ZONE 35. Ouachita Mountains, Northern Oklahoma and Arkansas, Southern Kansas to North-Central Kentucky and Southern Ohio
Growing season: late April to late Oct. Rain comes in all seasons. Summers can be truly hot and humid. Without arctic fronts, winter lows are around 18 degrees F/-8 degrees C; with them, the coldest weather may bring lows of -20 degrees F/-29 degrees C.

ZONE 41. Northeast Kansas and Southeast Nebraska to Northern Illinois and Indiana, Southeast Wisconsin, Michigan, Northern Ohio
Growing season: early May to early Oct. Winter brings average lows of -11 degrees to -20 degrees F/-23 degrees to -29 degrees C. Summers in this zone are hotter and longer west of the Mississippi, cooler and shorter nearer the Great Lakes; summer rainfall increases in the same west-to-east direction.

ZONE 41. Northeast Kansas and Southeast Nebraska to Northern Illinois and Indiana, Southeast Wisconsin, Michigan, Northern Ohio
Growing season: early May to early Oct. Winter brings average lows of -11 degrees to -20 degrees F/-23 degrees to -29 degrees C. Summers in this zone are hotter and longer west of the Mississippi, cooler and shorter nearer the Great Lakes; summer rainfall increases in the same west-to-east direction.

ZONE 41. Northeast Kansas and Southeast Nebraska to Northern Illinois and Indiana, Southeast Wisconsin, Michigan, Northern Ohio
Growing season: early May to early Oct. Winter brings average lows of -11 degrees to -20 degrees F/-23 degrees to -29 degrees C. Summers in this zone are hotter and longer west of the Mississippi, cooler and shorter nearer the Great Lakes; summer rainfall increases in the same west-to-east direction.

ZONE 43. Upper Mississippi Valley, Upper Michigan, Southern Ontario and Quebec
Growing season: late May to mid-Sept. The climate is humid from spring through early fall; summer rains are usually dependable. Arctic air dominates in winter, with lows typically from -20 degrees to -30 degrees F/-29 degrees to -34 degrees C.