explain why cities located on the western coast of norway in northern europe near the cold artic circle have a milder climate compared to other places located farther inland at the lower latitudes

The reason why cities located on the western coast of Norway have milder climate than other cities father inland is the sea: the sea mitigates climate extremes, bringing rain, moisture, cloud cover, and other meteorological phenomena, that moderate the climate.

Besides, the northern coast of Norway manages to get a bit of the warmer climate from the gulf stream.