World and Nation

Sunny Skies and Fall Foliage

Sunny Skies and Fall Foliage

Will today’s sunny skies help produce intense colors for the autumn leaves? Or is it the cold temperatures and the soil moisture that matter? While there is still some debate in the scientific community on the exact details, it seems to be a combination of the three. Cool temperatures (but not below freezing) and lots of sunlight in the preceding weeks help to kill the chlorophyll and setup the formation of anthocyanins, which create the sharp red and purplish colors our eyes are accustomed to seeing. Obviously, plenty of soil moisture will keep the tree “healthy” and help it hold onto its leaves. So with our somewhat rainy summer, sunny Septembers (climatologically the sunniest month of the year for Boston) and a rapid transition to cooler temperatures, the color intensity of our autumn leaves is one of the best in the world.

While the foliage for northern New England has passed its peak, the surrounding Boston area is only at about 15–40 percent peak, according to the Massachusetts Office of Travel and Tourism. They expect the peak to occur sometime next week. Meanwhile, we have a high pressure to our west. So even though cloudy conditions will dominate the latter half of the week, the high pressure will keep us relatively cloud-free for the next 24–30 hours. So, anthocyanins up while you can!

Today: Sunny. North winds 5 to 10 mph. High 61°F (16°C).

Tonight: Clear. West winds 5 to 10 mph. Low 41°F (5°C).

Tomorrow: Sunny. High 64°F (18°C).

Tomorrow night: Mostly cloudy. Low 50°F (10°C).

Thursday: Mostly cloudy. A chance of showers in the afternoon. High 64°F (18°C).