Heat record in Longyearbyen, Svalbard

Longyearbyen is the “capital” on Svalbard. It is closer to the North Pole than to Oslo,
A few days ago they experienced a heat wave, reaching 21.7C a new record:

No it is not welcomed by the people there, although they enjoyed a day on the beach, or rather a bath in the harbour under the midnight sun:

I think the warmest I ever experienced in LYR was about +10C.

Yes that make sense. Average temp. in July is 8-9C.
Here is more climate details for Longyearbyen:

PS> The Midnight Sun will still be shining until end of Aug.

I wouldn’t expect that bathing costumes would be best sellers there. What was the sea temperature?