Our fall season begins Sunday

After a very hot August and early September, conditions across the Inland Northwest have finally felt more like fall over the past week. Until last Thursday, only 0.82 inches of moisture fell for the summer season that began in late June. However, a strong storm system dropped 0.74 inches of rain Sept. 12, almost as much for the period from June 20 through Sept. 11. Our seasonal precipitation for 2024 total has climbed to around 15 inches, still below the normal level of nearly 17 inches to date.

The storm system also brought in much cooler temperatures to the region last Thursday. After a high temperature of 96 degrees Sept. 7, it was only 69 degrees Sept. 12. For the first nine days of this month, the average high in Coeur d’Alene was a hot 91 degrees, compared to a normal high of about 78 degrees.

Speaking of fall, astronomical fall arrives Sunday, Sept. 22, at 5:43 a.m. As I’ve mentioned in previous articles, we have four seasons because the earth is tilted on its axis by approximately 23.5 degrees. During the summer, our planet is tilted toward the sun, resulting in longer daylight hours and a higher sun angle. As we’ve moved farther into September, the daylight hours are becoming noticeably shorter. Next Sunday, the event also known as the autumnal equinox, the entire planet will experience approximately 12 hours of day and night.

The reason the times are not exactly 12 hours apart on the first day of fall are complex. Our location in a particular time zone, elevation and the fact that the sun is not a singular point in space are some of the explanations. Here in Coeur d’Alene, we will have about 12 hours and 15 minutes of daylight on the first day of fall. Our length of day won’t be close to exactly 12 hours until Wednesday, Sept. 25 when we’ll have 11 hours, 58 minutes and 26 seconds of daylight. On Sept. 24, it will be 12 hours, 1 minute and 51 seconds of daylight, so we’ll be a little closer to the 12 hours on the 25th.

The autumnal equinox, the first day of fall, and the vernal equinox, the first day of spring that begins March 20, 2025, have been closely observed by ancient civilizations. In fact, there are structures that were specifically built and ancient traditions observed for these astronomical events.

For example, Michaelmas, which is known as the Feast of Saint Michael, is celebrated in the United Kingdom by Catholics. Many people will feast on goose and according to the Centre Daily newspaper, renters would often gift their landlords with a goose to help maintain or renew their lease.

The Japanese people would honor their ancestors and relatives who have passed on during the autumnal equinox. They would attend to their ancestors’ graves and visit shrines and temples.

Ancient civilizations also built famous structures to observe the equinoxes. One of the most famous sites is the pyramid in Chichen Itza on Mexico’s Yucatan Peninsula near Cancun. The Kukulkan Pyramid, also known as El Castillo, is certainly an impressive structure that was built thousands of years ago and is listed as one of the Seven Wonders of the World. The staircase of the region’s highest structure has 91 small steps and at sunset of the autumn and spring equinox, a body of light will form in the shape of a serpent on the pyramid and move down its steps to eventually reach the carved head of the serpent called Kukulkan.

Perhaps the most famous ancient structure celebrating the equinoxes, and the winter and summer solstices is England’s Stonehenge. During the first day of summer, or the summer solstice, the sun will align perfectly with the giant heel of Stonehenge. Researchers believed that this structure was built to use the sun to track the seasons.

One structure in the U.S. is at Chaco Canyon in New Mexico. At this location, many structures have been discovered over time that track the movement of the sun. Fajada Butte is the most popular and during the equinoxes and solstices, detailed carvings will produce a perfectly positioned dagger of light on a wall.

In terms of our local weather, there is the possibility of more showers this week from a series of Pacific storms. We’re not expecting a lot of moisture from these systems this week, but we could see an increase in rainfall toward the end of the month. Our average September rainfall in Coeur d’Alene is 1.48 inches, and it’s very possible that we may come close to that figure over the next several weeks. Prior to the end-of-month storms, it’s looking like there will be a brief dry and warm spell.

Despite the below-average rainfall, we are expecting the moisture to increase across the region in October and November as sea-surface temperatures in the south-central Pacific Ocean continue to cool down. It’s very possible that a new cooler, La Niña, will be declared in the coming months.

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Contact Randy Mann at randy@longrangeweather.com.