Once in a while, the spring weather change can be comprehensive, but usually only lasts for a short while. Thus, we all of a sudden went from snow to +20C in the matter of two days. The natives read weather forecasts and are prepared for the heat challenge, whilst tourists obviously don't and do their sight-seeing attired in winter wear and woollen hats.
We might enjoy this until the weekend at which point the weather will be rainy and cold again.
Down town Oslo this afternoon, Nikkor Z 16-50 DX on the Z30.