Whatever the origin, Indian summer means pleasant weather in early fall

THURSDAY, OCT. 15, 2009

Much of the Inland Northwest endured near-record or record cold last weekend.

At the Spokane International Airport, the mercury dropped to 23 degrees on Saturday, which broke the record of 25 set in 1977. On Sunday, it was a frigid 20. The old record on that date was 24 in 2002. Last Sunday and Monday, the average temperature at the airport was only 30, which is 19 degrees lower than normal.

Now, the wet weather pattern and milder air has returned to our region. With all of this early cold weather and recent moisture, many folks have asked me if we’re going to see some additional warming, or an Indian summer-type weather pattern.

Indian summer is a brief, unseasonably warm period that tends to occur in late October or early November. It normally occurs just after the first hard freeze or immediately following a prolonged chilly and wet spell.

In this part of the country, we usually see at least a couple of periods of warm, dry and hazy weather during a typical fall season. Often, there are a few afternoons with record or near-record highs for the date, thanks mainly to a strong high pressure ridge over the region. This unusually mild air sometimes even reaches the normally cool and damp areas along the Washington and Oregon coastlines providing some spectacular conditions for residents and tourists.

There are a number of theories as to the origin of Indian summer. In “The Americans, The Colonial Experience,” Daniel J. Boorstin states that “the term originated from raids on European colonies by Indian war parties that usually ended in autumn.” The term was expanded to refer to the weather during that time of year.

Indian summer could also be of Asian Indian origin. H.E. Ware, an English writer, noted that ships traveling in the Indian Ocean loaded their cargo during the fair weather season, or Indian summer. Several vessels had an “I.S.” on their hull at the load level that was thought to be safe during that time of year.

The term may also be the traditional period which early Native Americans harvested their crops.

Early American settlers, nearly 400 years ago, observed Indian tribes “gleaning in the fields.” They likewise harvested late-season berries, nuts and pine cones from the nearby forests and dried fish caught in the lakes and streams. The Indian summer weather was normally followed by all-important tracking snows that gave the hunters an extra winter bounty of meat.

Following this much-needed wet spell, we should see at least a brief but welcome period of Indian summer weather. Afternoon highs may go above 70 degrees in parts of the region.

Then, shortly before Halloween, we should see the return of much colder temperatures and, perhaps, maybe even a few snowflakes in the lower valley elevations.

Contact Randy Mann at longrangeweather.com


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