It has been an unseasonable warm autumn, but autumn colors are on view in Lapland reaching already in Oulu.
Shortening of days is the most important effect to this, not the temperature. Also in this autumn the blight of birch has been
common in northern Finland. This has nothing to do with autumn colors (see the blight of birch!).
In this picture red leaves of bog bilberry (Vaccinium uliginosum) and some mature berries of lingonberry (V. vitis-idaea).

It has been a rather warm autumn, but now, at the end of October, the soil and plants
are hoar-frosted at least in the morning. The lingonberry and
most of mosses (Polytrichum in the picture) keep green colours over the winter,
but e.g. the bilberry (on the right corner of picture) has sheded nearly all leaves.
In the shady forest like this the leaves of bilberry will not get the autumncolors,
but the leaves turn lighter after the components of chlorophyll has been transfered
to the stems. Bilberry will start to assimilate with the green stems in spring already
in the snow before the leaves be born.