The western part of the country was particularly warm, with both Bergen and Stavanger recording new record high temperatures. Bergen hit 27.6C on September 16th, while Stavanger topped out at 27.3C on September 13th.
“Both cities had higher average temperatures in September than in July,” meteorologist Terje Alsvik Walløe said.
“There were consistent southern winds that brought warm air from the southern latitudes. There were hardly any northerly winds in September this year at all,” Walløe added.
Oslo equalled its monthly record with an average monthly temperature of 15C. Both Asker and Gardermoen beat their old records for high average temperatures, with 14.2C and 13.9C averages in September.
Further south, Kristiansand's 15C average equalled its record from 1949 and the mountains of southern Norway were up to five degrees warmer than normal.
Walløe said it was unlikely that the extraordinary warmth would continue through October.
“Thus far it doesn't look like there will be record warmth in October, but it's really too early to say,” he said. .