I haven't grown them and I'm not currently in the PNW, but I love perusing Raintree Nursery's website.
They sell several jujubes and mention to pick fruit early in cooler climates.

Here is a link that might be useful: jujube info

I've only seen it growing and fruiting in California, which makes me suspicious. I bought and planted a bare-rooted one once, it never budded out.

I tried them near Portland, much warmer than Seattle, and they didn't seem to have a chance to be able to ripen fruit. I ripped them out.