It is quite unfair to write about a rather pessimistic weather outlook for Stockholm, when today, we have fantastic weather, with predicted 21°C, and 19°C tomorrow.

But then, the GFS outlook looks unusual chilly (even cold), for the next 2 weeks. That is what kind of surprises me a bit. For example: after today, there are no 20°C in sight. Albeit we soon reach that level being a normal maximum for this time of the year.

I certainly hope that the chilly weather will either ebb out, or perhaps might go into a different direction. Right now however, the GFS outlook for Stockholm doesn't look particularly promising.

Min / Max Average

I put in the average MAX and Min temperature line for Stockholm City. That way you see how much the prognosis temperature would differ from normal temperatures. It is quite a deficit, I must say...

This is how things look like now in the morning. Not a single cloud over large parts of Sweden. The low pressure area, which created low temperatures earlier, especially in the Baltic with just 3-5°C, has moved towards Western Ukraine.

And then ?

Apparently something will be developing in the extreme North of Scandinavia. So far, i have not seen much indication yet. Apparently something it will lead cold air straight from the north southwards over Scandinavia - and then an intensifying low pressure area develops, centering over Stockholm - without moving henceforth. Therefore it could take a week until it weakens by "filling up".

I am sure that the final details will be slightly different - which is very common with longer range prognosis. However it seems to be expected that Scandinavia will be under the influence of both cold air, and a low pressure system developing soon.

So. May 2025 in Stockholm, looks to remain in average around 1.5-2°C below normal temperature.

Is it unusual ? No

I don't think so. I am walking through various may month statistics for Stockholm since 1984, and realize, that a coolish May alt. a May with cool periods, isn't uncommon really. Happened both in the 80s, 90s, 00s, 10s and even more recently in the 20s.

So. There is that.

Bias & premature expectations ?

I suspect there is a kind of impatience, a sort of bias involved too (in me I mean), when springtime starts to take off - which in nature it always does during may, whether it is cold, chilly or warm - there is always this impatience that i believe wants already have summer (temperatures above 20°C). But such temperatures are not always that often present. Some may months you barely reach 20°C, while at other occasions you even reach several 25°C temperatures.

Perhaps we have gotten used to the idea that May in Stockholm is on the verge of summer. The weather statistics however do not always agree to that. it STILL takes time for real summer to unfold. May is a springtime month, with quite some variability - especially when colder airmasses are coming from the north - it stays of course cooler.

We can be thankful for days with 20°C in May - but they certainly are not a rule to happen. Perhaps just 1-2 times in average ? Something like that. Other times, aplenty - like in May 2018 which was exceptionally warm most of the time, often reaching 25°C.

As was May 1993, another highly unusual May with exceptional high temperatures steadily until 24 May - and then it ended. From there on - was barely any summer heat to speak of for the rest of the season 1993. Stockholm had something like 1-2 days with 25°C for the whole summer (Jun-Aug).

That was it.