When a story takes place is part of its setting, along with where it takes place. Some stories may take place, be set, in a time period before they were actually written for historical period pieces, after they are actually written for futuristic or science fiction stories, or during the same period of time in which they are written. Clavert's The Hour of Dog falls into this third category.
Clavert's story was published in 1980, and the setting is contemporaneous to the period during which it was written and published. Therefore, the story takes place just prior to 1980. There is an Iditarod Trail dog-sled race from Anchorage to Nome in Alaska every year in the early spring (the date for the 2012 Iditarod is March 3, 2012). So the story, published in 1980, is set in the late 1970s.