This one is for people on the Pacific Slope. Spokane is ecologically in the intermountain region, try the Rocky Mountain Gardening forum.

I spent my teenage years just north of Spokane on a farm. We always had a large, good, veggie garden.

I don't think Spokane can really be compared with more easterly points in the Intermountain West. It has much drier summers, and gentler winters (a lot more plants can handle -5F every year than -30F every year). It would seem GardenWeb has forgotten the interior Pacific Northwest. I'd say to post away and who knows, perhaps more Spokane people will come out of the woodwork.

Anyhow... the Spokane Airport, it seems, is frost free from about mid May to mid September. That's in a cold pocket, so most livable areas probably have a longer growing season than that. Summer is consistently sunny and warm. You'll certainly need to irrigate. With an adequate water supply it should be a great climate for growing vegetables (fruit trees too).

My daughter lives in the city of Spokane on the south hill.
She has some productive fruit trees and grows a variety of vegetables. Her grapes are amazing compared to mine on the peninsula. Everything does need water. Soils seem to vary a lot over the area. When I go over, I like to visit Manito park and some of the nurseries just to see what does well.
Green Bluff just north of Spokane has a lot of farms that produce fruit and vegetables.
I have visited some back yard gardens with intensive edible production. Eggplants, squash and tomatoes grow well. She also had a longer time for harvesting sugar snap peas than over here. Lettuce, swiss chard and onions overwintered under the very deep snow for the last two winters - 6 feet in the back yard!!!
I would take Spokane any day over the hot, humid,buggy summers in Pennsylvania. We spent 3 years there - hail storms, floods, no-see-ums, black flies, rattle snakes.

Washington Biodiversity Project puts Spokane in the Okanogan ecoregion, just west of the Canadian Rocky Mountains ecoregian.