We have booked a trip south bound through Finland and then Norway to see the Northern Lights and wondering how cold it is going to be (roughly) and what suitable clothing required?
You can check earlier weather conditions in statistics of a place on yr.no (searh by date). Example Tromsø:
https://www.yr.no/en/statistics/graph/1-305409/Norway/Troms/Troms%C3%B8/Troms%C3%B8
Layers of clothing are always a good idea. As you need clear skies the temps will be low. Warm head and warm feet are key for staying longer oustide.
Do you mean March 2025?
I went on a Northern lights trip to Tromso, Norway in early February this year and it was cold! You should also consider that when you go on a Northern lights tour, you’ll be standing still outside in the snow for several hours. That requires several layers of good winter clothing and sturdy warm shoes.
It's very tricky to predict the weather seven months in advance, especially when you're not telling us where you're going.