Fall: The average date of the first frost is September 15. Begin watching weather reports at this time in order to protect frost-sensitive plants. Even after the first frost, we can usually expect several weeks of warm temperatures.
Winter: Freezing temperatures, snow and ice. When planning your garden, consider that we are mostly in USDA Zone 6, but we can plant a large variety of plants by using protective methods such as mulches, tree wraps, wind breaks and utilizing micro climates for more tender plants.
Spring: It teases us with warm weather one day and frost the next. It can stay cold and wet for quite some time as well. Be prepared to protect plants with covers, hot caps or row cover. Planting a little late is the safest method. May 15 is the average last frost date.
Summer: Temperatures can be quite hot, sometimes reaching 100°F. It’s a dry season so we recommend drought-tolerant plants. Plan to irrigate. Our long summer days provide lots of sun for beautiful flowers. Vegetables grow well, but we do recommend short-season varieties when possible.
WSU Extension website: