I connot speak for your area, but here the rain is not the problem... it´s only the temperature below -15-16°C.

But here we have a long vegatatuion time, even this week the Palms become new leafs. I cannot compare with Gothenburg! Maybe tehre´s is a bit warmer in winter nights as here, but also very long cold!?
Long periods below zero are also a problem for trachys.
So try it... ;-)
It´s definitely an advantage, if your T-Minimum is not under -10°C...

Location:
Here in my garden i made the experience, that a sunny location is better, because in warm february-sun the soil becomes warm faster... that´s good for the roots and the absorption of nutrients out of the soil.
If you have lots of rain so put it in sunny location in a good microclimate...

Here in Nürnberg it´s very arid in winter so i have to water the palms (at sunny locations) in winter, too. The evaporation is with evergreen plants also in colder winter-sun a huge problem. This is the only one advantage of a shadow place in winter...

Greets.