Oct 6, 2017 By Jack Hughes for The 3 min read

The month of September ended up showing temperatures averaging just about one degree above normal; however, when you think back to our weather for the past month, it was anything but normal. The first two weeks temperatures averaged seven degrees below normal and plenty of cool crisp bright sunny days.

The last two weeks of the month saw just the opposite with the thermometer averaging eight degrees above average and a lot of sunny hazy summer-like skies. Most areas saw a few readings close to or better than 90. After the rainy months of July and August, the sunshine was welcomed, but it was on the dry side and October is continuing the same dry, sunny weather.

This past weekend, we saw temperatures fall into the low- to mid-30s in the mountains and the mid- to upper-30s in the lower elevations. This did produce our first frost, especially in open fields and valleys and set the stage for our first period of Indian summer weather. The past few days with their cool mornings and sunny pleasant afternoons are typical of an Indian summer weather pattern.

The real cause of this weather pattern is a broad area of high pressure which brings fair skies, light winds and pleasant temperatures. Hugh pressure systems have subsiding air and this inhibits clouds and rainfall. These systems also can get well established and sometimes will linger over the area for several weeks.

Some years, we will get several periods of this pleasant weather, while other years tend to be more cool and wet. Those of you with home barometers will note that the readings this week have been well in the 30s.

As I write this article on Tuesday evening the reading is 30.52, which indicates a strong high pressure system.

Looking ahead to October, forecasters generally agree that the month should continue on the warm and dry side. This should set the stage for more periods of pleasant Indian summer-like weather. It should also delay the annual fall foliage show. Recent years have seen the peak color a week or so later than several decades ago.

I can remember October 3 and 4 in 1974 when snow fell across all Southwestern Pennsylvania. Roof tops and grassy areas had a coating in the lower elevations and about an inch accumulated in the mountains. Temperatures in Uniontown dropped to 24 degrees on October 4 and 25 on October 5.

In the mountains, it was even colder and the intense early cold caused the leaves to turn brown and fall off, making for a disappointing fall foliage season.

The average temperatures for October are a daily maximum of 63 degrees and a daily minimum of 42 degrees. Records are 16 degrees set back on October 20, 1992 and 95 degrees set back on October 2, 1927. Enjoy the nice weather.