Rain showers returned to North Idaho during our “new moon” cycle in early September. Temperatures were also quite chilly as highs were only in the upper 50s last Tuesday. Ten days prior, on Aug. 29, our high was a hot 91 degrees at Cliff’s station in Northwest Coeur d’Alene.

With the increased rainfall and cooler temperatures, I’ve received several questions from readers. The first one is, “When will we have the first freeze?” The other one is, “Are we going to have an Indian summer?”

For the first question, our first freeze with temperatures at or below 32 degrees in Coeur d’Alene is expected around the early to mid October period, a little later than normal. Cliff told me that he’s not changing over his system from air conditioning to heat until Sept. 27.

According to the National Weather Service, the average date with a 50 percent chance of a freeze in Coeur d’Alene is Sept. 30. At the Spokane International Airport, the average date is Oct. 7. Other gardening and data-type websites put Coeur d’Alene’s normal freeze chances around Oct. 5. Much of variance likely depends on proximity to the lake and other features.

According to Cliff’s records, the earliest date when Coeur d’Alene reported a temperature of 32 degrees was on Aug. 25, 1910. The record for a temperature below 30 degrees occurred on Sept. 7, 1929, with a low of 29 degrees.

By the way, early freezes have already been reported in southeastern Idaho, western Montana and Wyoming. Up to 10 inches of snow was seen in the higher elevations of western Montana during the Labor Day weekend. If that dip in the jet stream was a bit farther to the west, then we residents in North Idaho may have talking about record low temperatures and perhaps a few high elevation snowflakes.

As far as the second question, Indian summer is an unseasonably brief, warm period that tends to occur in the midst of autumn in late October or early November. It normally happens just after the first hard freeze or immediately following an exceptionally 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 conditions 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. It was the extension to the summer-like weather conditions in the fall as Indian summer.”

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, about 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.

In terms of local weather, high pressure will be locked in over our region through the upcoming weekend. We could see some showers develop around the early to mid portion of next week during the “full moon” lunar cycle before turning briefly drier.

Shower activity should start to pick up again during the “new moon” cycle beginning on Sept. 30. Then, conditions should turn dry and mild toward the middle of next month, probably an Indian summer-type pattern.

As we’ve been mentioning for quite some time, the upcoming winter still looks snowier than usual. There may be some snowflakes in the lower elevations by late October, but the heavier stuff is not expected until at least the middle of November.

Stay tuned. Sea-surface temperatures are changing almost on a daily basis. I’ll have an update on the chances for the cooler La Nina next week.

Contact Randy Mann at randy@longrangeweather.com