Places north of the tropics where September is the 5th warmest month of the year (climate, hottest)

[Glacierx]

This means that May, June, July, and August are warmer. I would expect this in the north, but I'm really surprised to find it in Texas, especially with no other points south of the Canadian border.

Here are a few places that I find:

Alpine, TX
Rio Grande Village, TX
Indian Head, SK
Lloydminster, SK
Fairbanks, AK
Tok, AK
Edmonton, AB
Rocky Mountain House, AB
Revelstoke, BC
Fort Nelson, BC
Zhota, MB
Emerson, MB
Watson Lake, YT
Whitehorse, YT
Fort Liard, NWT
Fort Simpson, NWT

[Ariete]

Around every place within this area:

[Anhityk]

Originally Posted by Ariete

Around every place within this area:

You may budge the eastern frontier towards Pacific ocean a bit, just made a weatheronline.co.uk calculation for city of Chita and occured to me that their May averages are higher than in September.

[Qilin34]

In Xinjiang, PRC:
Turpan
Kashgar
Hotan
Karamay
Altay
Hami
And marginally, Ürümqi. Although I haven't checked all stations, these comprise the bulk of the major cities in the region and extrapolating tells me most of the Dzungaria and Taklamakan basins are warmer in May, if only slightly.

Dunhuang, Jiuquan, and Zhangye in neighbouring Gansu also qualify, but the line seems to stop there. South and east of there, the cooler highs in September seem to be made up for by warmer lows.

I've checked Baotou and Hohhot in Inner Mongolia, and they also make the cut, but the rest of the region is not clear; seems to be a localised issue.

[Jakobsli]

On the other hand, there are many places in the far north where September is the 4th warmest month (warmer than May).
Hammerfest - Wikipedia, the free encyclopedia - September mean 3.4C warmer than May; the climate data in the article is accurate using 1961-90 data.
St. John's, Newfoundland: September mean 6C warmer than May.

Returning to your question...in Norway it's only inland areas in the southeast where September is the 5th warmest month (slightly colder than May), such as: Lillehammer, Hamar, Gardermoen, Nesbyen.

[Glacierx]

Some places (namely in California) have September as the hottest month of the year including San Francisco, Berkeley, and Richmond.

Still others have September as the 2nd hottest month of the year. Outside of California (of which there are dozens of places) we only find 5 places in the USA and Canada: Weston, FL, Sable Island, NS, Deming, NS, Cape St. James, BC, and Shemya USAF Base, AK.

[nei]

So cool summer oceanic except for Weston which probably has weak seasons.