Viking horses were probably the most hardy ones found in the entire world, they could plough through any terrain in any weather carrying a heavy Scandinavian on their backs. Norwegian fjord horses descend from their Viking ancestors. Horse riding is a year-round activity, but it seems a bit unreasonable to ride the strong jumpers in dry summertime when they can endure much more. Severe snowy season stretching from November to March allows the riders to try everything the Norwegian horses are capable of.
One of the best spots to experience horseback riding is Geilo Hestesenter in Geilo.