Short answer is yes.  In Portland, rain is very common and mainly it is manageable with a canopy our units are equipped with.  The canopy needs some room to setup so there will need to be at least 5 ft clearance around the serviced vehicle plus close access to the service unit.  If wind is above 20 mph while raining there is a possibility of reschedule.  Please contact us if you think the weather will be an issue at time of service.