I know it is common to refer late summer/early fall high temps as a indian summer, but I believe there is an actual criteria for it. I believe when those temps arrive after a freeze or something. Anyone here know?
2007-12-10 22:57:13 · 5 answers · asked by blueshoe711 4 in Science & Mathematics ➔ Weather
True Indian Summer is a period of abnormally warm weather following the first killing
freeze of autumn. A killing freeze occurs when the overnight temperature reaches 28
degrees of cold…and may or may not occur with frost. Indian Summer typically occurs
in mid to late autumn and can occur more than once.
This is all I know.
2007-12-10 23:12:50 · answer #1 · answered by clio skywarn 3 · 3⤊ 0⤋
From a British meteorology book I read many years ago, it appears that northern Europe is under the influence of frontal lows passing at the average of one every two days. That is because they are dragged by the jet-stream winds high up in the atmosphere.
But, on the average of three times a year - and without specific reason - those jet-stream winds weaken to nearly nothing. Those are the periods of the year when a high pressure has chance to build up over Northern Europe and give dry and sunny weather.
On average, that happens in June, September and January. When it happens in September - October, we call it Indian summer. When it happens in January, it brings frost because the sun is low so low over the horizon that no heat is gained.
For different latitudes, there is a 'break-even' date before which each night of clear sky dissipate heat more than it can be gained by daytime. For each day the high pressure last, the temperature sinks. After that 'break-even' date each sunny day increases the daily average temperature.
That date varies from February to April in northern Europe.
2007-12-11 08:06:46 · answer #2 · answered by Michel Verheughe 7 · 1⤊ 0⤋
Indian summer is a name given to a period of sunny, warm weather in autumn, not long before winter. Usually occurring after the first frost, Indian summer can be in late October or early November in the northern hemisphere, and late April or early May in the Southern hemisphere. It can persist for a few days or extend to a week or more.
2007-12-11 07:01:02 · answer #3 · answered by Anonymous · 2⤊ 0⤋
It is a phrase that relates to high or unseasonable warm temperatures after an Early Freeze and precede the winter cycle.
2007-12-11 08:10:04 · answer #4 · answered by blueridgemotors 6 · 2⤊ 0⤋
It's used figuratively to describe a late blooming or period of creativity towards the end of an artist's or musician's productive life.
2007-12-11 07:02:42 · answer #5 · answered by Bart S 7 · 1⤊ 0⤋