Classic Indian Summer Unfolding In Northern New England, SE Canada

Morning fog breaks up to reveal bright
fall colors during a 2012
Indian Summer in Vermont.  

One of the big joys of autumn is Indian Summer, and parts of northern New England, the interior Northeast and southeastern Canada are in the throes of a perfect one now.  

Indian Summer is loosely defined as a period of sunny, warm, calm weather after some of the autumn's first frosts.

Most of the area now heading into Indian Summer had a big frost last week. That chill is  all but forgotten as temperatures will rise into the 70s under sunny skies for the next few days.

The core of this Indian Summer, with the best weather now through Sunday, will be in northern New York, Vermont, New Hampshire, Maine and an area of southeastern Canada including Ottawa, Montreal and Quebec City.

A very common fall weather pattern causes Indian Summer. Sprawling, slow moving high pressure systems often linger over the northeastern United States or southeastern Canada this time of year.

High pressure systems feature sinking air. Clouds need rising air to form, so the sinking air encourages clear skies.

The air in these autumn high pressure areas is often dry, so you get cool nights, but warm days with the sun.

The only major exception to the "no cloud" rule during Indian Summer is dense morning fog, especially near rivers and lakes. Pretty much every morning now through Sunday will feature patchy early morning fog.

The air cools off a lot at night during Indian Summer. The ground, rivers, ponds and such are still pretty warm from the recently departed summer. As the air cools, the relative humidity goes up and the moisture from the warm-ish rivers and ground, etc. forms a dense fog.

On the negative side, dense fog is dangerous because anyone who's driven through it knows you often can't see a damn thing it's so thick.

On the bright side, the morning fog is almost always a sign of another beautiful day in store. The rising sun will quickly dissipate the fog, usually by mid-morning.

A Pro Tip here: If you want to photograph fall foliage, get out there when there is dense morning fog. Yeah,  I know you can't see the foliage through the fog, but just wait. The rising sun, with its low angle, combined with dissipating fog around brightly colored trees, often leads to some spectacular photos

Try it, you'll see.

Speaking of foliage, this current Indian Summer is hitting when the foliage is getting very colorful in some areas. The High Peaks of the Adirondacks, the Northeast Kingdom of Vermont, far northern New Hampshire, the mountains of western Maine and the Laurentians of southeastern Quebec are approaching peak color.

Lower elevations to the south of this region have some color, and it's nice, but there's still a fair amount of green.  It's still worth a look at the colors in those areas if you can't head to the north and mountains.

As always, Indian Summers have several days of wall to wall sunshine, but there are interruptions. The first nor'easter of the season is causing a rainy day in the mid-Atlantic states. That huge high pressure system causing the Indian Summer will block that nor'easter from reaching northern New England, but it will throw a few clouds into the sky today.

A cold front heading due south from Quebec later Sunday and Monday will cool off the weather a bit and create some clouds next week, especially since an east wind behind the front will bring in some low clouds from the Atlantic Ocean into parts of northern New England.

But meantime, enjoy this spectacular weather.



Go out and enjoy during this Indian Summer.

There's early foliage viewing to enjoy

After The Frost: Indian Summer?

Much of Vermont got a frost last night, as expected, but a few areas, especially near Lake Champlain  did not, again as expected.

The low temperature in Burlington, Vermont was 35 degrees, missing the record low for the date by just one degree.

Warm hazy fall days are regarded by many as
Indian Summer, but there is disagreement
on precise definitions. 

We know it's going to warm up for the rest of the week, but do you call the mild spell an Indian Summer?

It turns out the answer is complicated. For many people, any spell of warm, sunny weather after an autumn frost or freeze is an Indian Summer. 

So, if your garden is wilted and iced this morning, but you find yourself enjoying the warm sunshine tomorrow afternoon, congratulations, it's Indian Summer for you

Other definitions of Indian Summer are a lot more persnickety. The Old Farmer's Almanac is probably the biggest hardliner it in its definition.

To them, Indian Summer must be a spell of hazy, sunny weather with warm days and cool nights, and it has to come between November 11 and 20. As you can imagine, that means most years don't have an Indian Summer, at least in the world of the Old Farmer's Almanac.

But as I said the rest of the week in Vermont is going to be nice. Temperatures in the lows 60s today will get to 70 Wednesday and into the 70s Thursday and Friday. We'll have a decent amount of sun during that time, too.

So if you want to call that Indian Summer, go right ahead. But if you just want to call it nice, knock yourself out.