Non-ice cap places that reach above freezing average highs at the latest date? (climate, warm)

[wawa1992]

Resolute, Nunavut is a very cold place, and is inhabited by 229 people. The average high here reaches freezing only on June 9 and falls below freezing September 7. That's a total of just 91 days with an average high above freezing. It's not uncommon for above freezing temperatures to be wholly confined to the four months of June, July, August, and September. In fact, the coldest years can have their first above freezing date as late as June 20 (this happened in 1978) and last above freezing as early as August 20 (this happened in 1997).
Alert, Nunavut, even farther north, has a slightly cooler June average high (implying they hit freezing likely a few days later, maybe around June 12), but the mean of their Aug and Sept highs is -1.3 C (compared to +1.1 C for Resolute), which would imply that Alert's average high has probably dropped below freezing before September 1, probably around August 25-30. Exact data is not available for Alert on WeatherSpark though.

So June 9 - September 7 for Resolute (75 N). 91 days. Interestingly enough, early June seems to be a common time for average high temperatures to hit freezing in the high Arctic.
Other early June locations in the Canadian Arctic include:
Go north to Eureka (80 N), and it's June 3 - September 5, for a total of 95 days.
On the north coast of Baffin Island, Arctic Bay (73 N) has an above-freezing high window of June 1 - September 23. 115 days.
Nearby Pond Inlet's window is June 1 - September 22, for 114 days.
Clyde River (70 N) is June 2 - September 28. 119 days.
Longstaff Bluff (69 N) is June 4 - September 24. 113 days.
Hat Island (68 N) is June 6 - September 26. 113 days.
Cambridge Bay (69 N) is June 3 - September 24. 114 days.

It seems that in the Canadian Arctic Archipelago, early June is when it hits freezing. I find it odd how Cambridge Bay, at 69 North, and Eureka at 80 north both hit freezing average highs on the same day. May dates are only found in the far south (below the Arctic Circle, such as southern Baffin Island) or once you hit the Canadian mainland. Latitude and warmth do tend to affect the date when temperatures return below freezing (notice that it's early September for the colder higher latitude locations and late September for the warmer locations) and the peak average temperature at the height of summer (Resolute averages 45 F / 8 C high at the peak of summer, and Cam Bay's is 56 F / 13 C, nearly enough to make it subarctic).

Outside the Canadian Arctic, there are certainly other locations with similar tundra climates. Siberia and northern Greenland, for instance, are full of them.

So what is the latest in the year (e.g. June) that a non-ice cap climate hits a freezing average high? What's the earliest in the year (e.g. Aug-Sep) that a non-ice cap climate falls below freezing average high? What's the shortest window?

[kronan123]

ostrov vize has a short window. 70-80 days perhaps?

[Mhc1985]

The McMurdo Dry Valleys!