If you’re looking forward to lots of outings with your partner, check out these details about year-round temperatures in Nikiski: The hottest months are usually July and August with an average temp of 54°F, while the coldest months are January and December with an average of 23°F. The snowiest months in Nikiski are December, November, February, and March, with each month seeing an average of 8 inches of snowfall.