Portland sits in the same cold-moderate climate band as the rest of the area, which means winter cold snaps tighten steel and stiffen old grease on hardware that's already thirty years worn. A spring near the end of its life is far more likely to snap on a cold morning than a mild afternoon, because cold steel has less give before it fails outright.
The other local factor is simply household math. Portland has roughly 4,907 households, smaller than the area's 29,110, and median income here runs about $72,380 - a bit under the wider service area's $78,597. That doesn't change how a spring fails, but it does mean we see more owners choosing a targeted repair over a full door swap when the budget allows for one but not the other, and we price the job accordingly rather than pushing a replacement nobody asked for.