In Greek it's "Halcyon days", after Halcyone (or Alcyone) the daughter of Aeolus:

https://en.wikipedia.org/wiki/Alcyone_and_Ceyx

The phrase "halcyon days" seems to be used in English also for the warm days in the middle of winter:

https://en.wiktionary.org/wiki/halcyon_days

I'm not sure how common this warm mid-winter period is in general but I've certainly noticed it in the 15 years I've lived in the UK and it must have been common in Greece in the past also. In recent years, also, but Greek winters in modern times tend to be very mild anyway. Nothing like in Norawy, I'm sure :)

Interesting, I am Norwegian, and have never ever heard this phrase in my life

I've heard it frequently growing up in tromsø.

We have our share of bizarre weather this winter - while it's customary for snow to melt right before Christmas - I can't recall there being this little snow not only in December - but through Christmas and well into January.

I just went for a walk and watched people skating on the nearest pond - which is usually frozen this time of year, but also covered in a meter or more of snow.

Meanwhile they're having a white Christmas in Bergen.

Oh I loved visiting your city in the summer, hope to have a chance to visit again in winter!!

That's how things were last year here in Lithuania. We never had a proper winter. This year it seems about normal in terms of snow, but temperatures feel a bit warmer (most of the season its been hovering around 0c, but is usually -10c)

Same here, TIL!

Ditto