To be honest, it's apples and oranges. The only one I would trust is the sunset zone classification, because the rest are based on winter temps. and not relevant to most vegetables (barring overwintered vegetables of course).

Now regarding those three based on winter temps., some may have taken the *lowest* winter temperature ever recorded. For Coquille, that is 12 F. That's zone 8 or bordering on 7b for inland locations. However, most years won't see a low of 12 F. especially if you are right on the coast. That explains the zone 9 classification. I'd say this is the most correct of the three because it considers the average annual coldest temperature recorded, not the lowest low possible. For example, we typically record an annual low of -40 F here in zone 2, but the coldest ever recorded was -56 F.

Your zone 9 is of course worlds apart from a zone 9 in Texas. That's why you shouldn't put too much emphasis on zone classifications based on winter temperatures.

This post was edited by Slimy_Okra on Wed, Jun 12, 13 at 2:44

Concur. USDA zones are intended for hardy plants and are useless for most vegetable crops. The Pacific northwest is classified as zone 8 but the climate is quite different form zone 8 Georgia. Our winter temps may be similar, but summer is an entirely different story and these zones are based on winter temperatures. We can both grow short day onions in the winter but that is about the end of similaries for vegetable growing.

I am on the East "slope" of the Coast Range Mtns. Our Summer weathers are so so different that zone classification for your micro climate IS almost irrevelant. I would say that you are more like Zone 8 than anything else.

For those unfamiliar with the Oregon Coast...their Summers are much cooler and sunless and the Winters are much milder and sunfilled than 50 miles away. This is why when folks post questions or comments on this forum it is important to give zone and location.

You might want to post in the Northwestern Gardening Forum.

http://forums.gardenweb.com/forums/nwest/

Here is a link that might be useful: NW Gardening Forum

All of the above comments being relevant, have you check out inks similar to the one below?.

Here is a link that might be useful: Oregon State Planting Guide

The definitive resource is the USDA Plant Hardiness map, which less than a year ago was updated. You are in zone 8b - 9b depending on where in Coos bay you live.

Please visit USDA Plant Hardiness Map

To further specify what others have said: you are probably in Zone 9 (it seldom freezes), but do not think that you can plant figs, or even eggplants. Your vegetables will be greens, roots, and some squash and beans. Cool season crops, because it seldom goes above 80 in Coos Bay. Similar to what you would have in the United Kingdom. But you can garden year round, unlike most of us.

Let me add that as a former Oregon gardener, now in central Texas, the hardiness zones don't really mean squat for vegetables. I'll tell you why. I was in 8b in the Willamette Valley. I'm now in 8b in Central Texas. Is Willamette Valley veggie gardening ANYTHING like central Texas gardening? Nope. Not by a long, long shot.

The hardiness zones are really indications of how cold it gets in the winter. That's useful for trees and shrubs,which you'd like to have survive over the winter. That is, I probably have as much hope of an avocado tree surviving here as it would there. The zones give absolutely no indication of what the summer is like, which is the big difference for me.

DO NOT manage your veggie gardening according to these zones. As noted above, local gardening forums would be far more helpful.

Please take daninthedirt's comments with a "grain of salt"...anyone who would leave the beautiful verdant Willamette Valley for Central Texas should have their head examined!!!

Eh, don't rub it in. (But well put.) You go where the jobs are. Yes, I really miss that locale. I grew up there. Now, I can grow heaps of okra, eggplant, and hot peppers here with ease, my cherry tomatoes are 8-feet tall, and I've got TWO growing seasons. But I really miss the berries (I would kill to grow blueberries ...) and the lack of SVBs. While the winters here are wonderful, deep summer is an, er, challenge.

Going back in a few weeks on my yearly visit! Now, when I go back there in summer, the sky is always clear and beautiful. Why do I remember it otherwise? Oh yeah, there are the other nine months of the year!

Well said. Zone classification is just indicative poor correlation. It is more like the length of growing season in months. It does not reveal any relevance to temperature pattern.
EXAMPLE: I am where it is 7b to 8. Last night low was 48F, tonight and tomorrow nights will be the same. Our last frost date was around mid April I think. That was two months ago. Somewhere down south at zones 7b and 8 they are harvesting okra but I am worried about my squash seedlings..hehe