The Fall Foliage Lab

Colorfall is a small, free web toy about the autumn colour phenomenon that is happening across the Northern Hemisphere right now. It does three things: it tracks when the colour reaches a place, it lets you play with leaves and pigments, and it teaches the science and the world traditions behind it.

It is a “daily site” — it lives on the front page of dailyma.de for one day only, then moves to a permanent archive. Everything here works on the day it launched: there are no unlockable days, no daily challenges and nothing that waits for a future date.

It is a static site — plain HTML, CSS and JavaScript, no backend, no accounts, no trackers. Your scores, collection and saved palettes are kept only in your own browser’s local storage.

The Peak Finder is built on a dataset of 60+ leaf-peeping destinations. Each one has a typical peak window for an average year, along with its latitude, elevation and dominant tree species. Those windows are compiled from the Old Farmer’s Almanac’s 2026 fall foliage forecast, national and state park foliage calendars, tourism boards and the sources below.

For any given week the site compares the date to each destination’s window and sorts it into one of six stages: green, early colour, near peak, at peak, fading, or fallen. The “colour wave” chart places every destination by latitude and by its typical peak week, so you can literally watch the colour roll south as the season advances.

Please read it as a guide, not a guarantee. Autumn timing varies by a week or more with temperature, sunlight, rainfall, wind and early frost. Always check a local foliage report before booking a long trip.

During summer, chlorophyll masks the yellow and orange carotenoids already in the leaf. As days shorten and temperatures fall, the tree stops making food, the chlorophyll breaks down, and those colours appear. Sunny days and cool nights trap sugar in the leaf, driving the active production of red and purple anthocyanins — which is why the best reds need good weather. Brown comes from tannins and the breakdown of cells. A layer of cells called the abscission layer then seals the leaf off and it falls.

Colorfall was researched and built as a single-day web studio project. All leaf illustrations, page layouts and interactive tools are original. The facts, numbers and traditions below come from these sources:

• Wikipedia, Autumn leaf color — chlorophyll breakdown, carotenoids, anthocyanins, tannins, tourism and climate influences.
• Wikipedia, Leaf peeping — the term’s origin (Bennington Banner, 1966), momijigari, ruskaretki, dan pung ku gyeong and shangye traditions.
• SUNY College of Environmental Science and Forestry, Why Leaves Change Color — pigments, weather effects, abscission.
• The Old Farmer’s Almanac, 2026 Fall Foliage Map & Peak Leaf Color Forecast — regional peak windows and the typical seasonal progression.
• USDA Forest Service / US National Arboretum materials on autumn colour in broadleaf and conifer trees.
• Wikipedia species articles for individual trees (sugar maple, red oak, ginkgo, sweetgum, sassafras, black tupelo and others) for leaf shape, range and colour.
• National park and state tourism foliage calendars (Acadia, Great Smoky Mountains, Shenandoah and others) for destination notes.

Peak windows and palettes are representative approximations for an average year. Species and destination descriptions are simplified for a general audience.

Colorfall is built mobile-first, works down to a 320px-wide screen, and supports both light and dark themes (following your system setting, with a manual toggle). It uses semantic headings and landmarks, visible keyboard focus, sufficient colour contrast, and respects prefers-reduced-motion. The games are fully playable with the keyboard. Charts carry text alternatives, and every interactive control has a label.

If your browser blocks local storage, the site still works — it simply won’t remember your scores.

Colorfall is general-interest information, not travel, safety or medical advice. Peak dates are historical averages and can shift. Check current local conditions, park alerts and road closures before you travel.