My brother has a rooftop terrace adjacent to his work condo in the Pioneer Square area of Seattle and grows a variety of containerized plants there, including azaleas and has for 20 some years. Azaleas are quite hardy and can take the PNW weather quite easily, even in containers. His only issue is this is a south facing terrace with unrelenting sunlight and so he pays very close attention to watering needs in summer.

I don't grow any myself but they are very commonly grown in pots here because so few areas have acid soils which suit them. In a pot you can make sure the shrub has an Ericaceous mix. Perfectly hardy in our similar relatively benign climates. BTW water with rain water if your tap water is alkaline.

Placing your potted azalea in a larger pot will help keep it cooler during the summer and help it protect it from the coldest of the cold during the winter. Like now. Woodchips or peatmoss in the void between the pots will help it even further.