Method & Disclaimer

How the timing on this site is estimated, what we do not have, and who we are not.

In detail

What this site is

Fall Foliage Map is an independent seasonal outlook for four states: Wisconsin, Minnesota, Maine and Vermont. For each state it breaks the season down by region, names the tree species that carry the colour there, and lists the numbered highways and named public lands where that colour is easiest to see. It is not affiliated with any state tourism office, park service or government agency.

How the timing is estimated

Every peak window on this site is a historical norm, estimated from phenology — the study of seasonal biological cycles. Three factors drive the sequence, and they apply in this order. Latitude sets the baseline, so northern regions turn before southern ones. Elevation modifies it locally, which is why a mountain gap can run several days ahead of the valley beside it. Species mix sets the texture, because sugar maple, quaking aspen and tamarack each run on their own clock rather than on a single shared calendar.

What we do not have

We do not have a real-time canopy data source. There is no satellite feed behind this site and no field observation network. The predictor on the home page is a selection tool built on historical norms — it tells you which region usually turns when, not what is happening in a given county this week. We think being explicit about that is more useful than implying a live map we cannot deliver.

Accuracy, honestly stated

The sequence is dependable. Which region of a state turns before which is governed by latitude, elevation and species mix, and that ordering is stable from year to year. The dates are not dependable to the week. A hard early frost, a warm wet September or a dry summer will move a region by a week or more in either direction, and an early hard freeze can end a season abruptly.

Why only four states

Because those are the four where we can write something specific rather than something generic. The variable that matters is the pairing of a state with the way people actually phrase the search, and we have only systematically examined a small part of that space. Publishing four states with real regional detail is more honest than publishing fifty with filler, so that is what we have done.