As summer gives way to fall, here's a cool visualization showing the annual changing of the seasons across the country, posted today on Reddit by MetricMaps.
The map shows each county's average daily high for each day of the year.
Smoothing out annual fluctuations revels the consistent patterns that occur across the country each year. For the most part, warm temperatures start in the south during early spring and gradually creep upward in uniform bands, but you can see how mountainous areas (like the Appalachians and Rockies) stay cold a bit longer, and never get as hot. Coastal areas, modulated by the temperature of the ocean, take a bit longer to heat up in the spring and cool down in the fall.
And in southwest Colorado, San Juan County — the highest county in the country — only makes it above 15.8°C (60.44°F) for a few weeks per year.