Alaska Weather > Kenai Weather Kenai, AK Weather Kenai, AK climate is cool during summer when temperatures tend to be in the 50's and extremely cold during winter when temperatures tend to be in the 10's. The warmest month of the year is July with an average maximum temperature of 62.10 degrees Fahrenheit, while the coldest month of the year is January with an average minimum temperature of 5.50 degrees Fahrenheit.