I've grown them off & on for about 10 years, currently only have a couple small ones. They like lots of sun, excellent drainage (almost cactus-like), and some fertilizer to bloom.
I like to use my regular tropical plant soil mixed 1:1 with extra perlite or pumice (prefer mostly pumice because it doesn't float to the top, making the soil appear drier than it actually is, like perlite can).
They can be very susceptible to root rot in the winters without high light & warm temps, but will also grow too slowly if not given enough regular water in the heat of summer. So getting the right amount of water/drainage is a delicate balance. Other plants like this (e.g. orchids) often require much less nutrients (allowing you use more barren soils that are easier to drain)... not plumeria. They like the richer soils to get blooms.
This year I think I'm going to try them in-ground, and store them over-winter completely bare-root in plastic garbage sacks like I've read about.
- Tom

Cuttings sold at big local flower show for years.

With the result that I've wondered for years how a shrub that grows in full sun in Honolulu would do indoors here during our frequently dull weather.

I'd be surprised if you can get them to do well as a houseplant in Washington state, or as in indoor in winter and outdoors in summer container plant. They really want and need 80F plus temperatures to grow well, along with bright sun, and if you can't give them sufficient heat and light in the warm months, they just tend to struggle along. Your best bet may be growing them in a south facing enclosed sunporch, if it has great light and warms up into the low 80'sF during the day.

Speaking from experience, they are marginal even here in the San Francisco Bay Area in areas closest to the ocean/bay, yet can do surprisingly well in more inland valleys or places like Sacramento, Fresno, Bakersfield, etc if summered outdoors as a container plant, and forced into dormancy in a protected spot indoors in winter. They barely bloom at all by the very end of summer here in Berkeley/Oakland outdoors, but I have seen thriving plants in a San Francisco enclosed west facing glassed in sunporch, which did bloom regularly.

They are very prone to getting scale and/or mealybugs if they are suffering from lack of proper heat, so be aware that you may have to constantly battle these. I wouldn't think they would do all that well west of the Cascades, maybe better in the inland, hotter summer areas. They will definitely tend to rot out even here in the SF Bay Area if left outside and rained upon in winter.

If you can give them the sustained heat in the warmer months that they prefer,(and this includes at night), they are perfectly fine even with dull sunless winters, when they can be allowed to go dormant and leafless, and just barely watered once a month.

It can be tough, but if you get your one or two sets of flowers a year the plans will do fine. Flowering = branching, and that's what keeps them from getting too leggy. I've tried overwintering them with my Brugmansias, under 1000w halides, but that area was too cool, and all I got was a lot of unwanted straight growth with no branching. So I've been keeping them in the basement (warmer) close under flourescents with a shorter photoperiod. Keeps them more compact and semi-dormant until I can get them back out.
I do know a few other people besides me who have kept them around here as a houseplant in the winter (best light) and then full sun/reflected heat in the summer. They'll never be as glorious as their southern cousins, but get whiff of one set of blooms and I guarantee it will all be worth the trouble. ;)
- Tom

I stayed growing them this year. I grow them from seed

I have a plumeria that’s five years old and i live in Washinton. Its currently about four feet tall and i have it in a planter on wheels so I can put it outside in summer. There are also tropical plants in the planter with it

I wait for it to be above 55F at night before putting it outside every year (generally in May) and bring it inside all winter. It hasn’t bloomed, yet but I’m going to try a tropical plant fertilizer to see if that will get some flowers this year