Door latches freezing

[RuppX5]

With the recent freezing weather in Seattle (I don't mean really cold, just below 32F) and snow / rain, my X5's door latches seem like they are freezing up. When I opened the door yesterday morning there was the typical ice build up around the door handle and the handle itself didn't move freely. Also, when I tried to shut the door, it wouldn't engage. I had to use a hair dryer to warm it up to the point that the latch would engage. I tried spraying silicone lube into the latch but that didn't do anything.

Has anyone encountered this and if so, what was the remedy? Is there a process to lube the door latches?

Thanks,

Mike