With the assassination of President McKinley, Theodore Roosevelt, not quite 43, became the youngest President in the Nation's history.
Average Temperatures in Oslo, Norway. 1  The average annual temperature in Oslo, Norway is cool at 5.7 degrees Celsius (42.3 degrees Fahrenheit). 2  There is a variation of average monthly temperatures of 20.7 C (37.3 F) which is a below moderate range.3  There is a range/ variation of mean daily temperatures of 7.3 C (13.2 F). There is a range/ variation of mean daily temperatures of 7.3 C (13.2 F). 2  The warmest month (July) is very mild with an average temperature of 16.4 degrees Celsius (61.52 degrees Fahrenheit). 3  The coldest month (January) is slightly cold having a mean temperature of -4.3 degrees Celsius (24.26 degrees Fahrenheit).
Southern Norway. Summer in southern Norway begins in June and extends through August. The season is marked by long, warm days with temperatures rising into the high 70s F. Sea temperatures reach the mid-60s F. Autumn weather takes hold of southern Norway during September and October.