Autumn is here - first frosts in the U.S.

Now that Meteorological Autumn is here, and next week the Autumnal Equinox, it is time to be thinking about the upcoming first frosts. For gardeners, farmers, and those who enjoy the fresh air of Fall, this will be welcome information.

September is, on average, about the time where meteorologists can begin to see cooler air from the North making its way into the US. This cooling can drop temperatures into the 30s and 40s, allowing for frost to form on the ground for many regions. You can keep an eye on the cooler air coming into the US with our interactive TemperatureRadar.

As expected, those in the North are usually the first to experience frosty mornings. Mid-to-late September is usually the time when frost forms on the ground for areas in North Dakota, Wyoming, Montana and Maine. The earliest is usually Caribou, Maine, around the Autumnal Equinox, but cooler air can make it in earlier at times.

At this time, we usually see cozy sweaters being worn, pumpkin-spice-flavored everything, and even the Halloween candy being stocked to the max in stores. Major cities that will see the ice crystals forming on the shoots of grass usually in October include Boise, Idaho, Denver, Milwaukee, Wis., Cleveland, and Providence, R.I..

The leaves have changed colors of red, gold, and yellow and have been falling into crunchy piles on the ground by November. Residents across the central and southern Plains, the Mid-Atlantic, the Tennessee and middle Mississippi valleys will notice the formation of the brittle ice on the fields as temperatures drop into the 30s and 40s in the night.

The Pacific Northwest, northern California, the Southwest, the lower Mississippi Valley, and eastward over to the Southeast Coast are usually the final areas to see frost as cooler air settles into the U.S. By this time, many holiday celebrations are taking place and residents in cities like Seattle, Jacksonville, Fla., and Houston, Texas, are bundling up for the coming cooler days.

These times, of course, are the average for first frosts. In fact, more suburban or countryside areas are more likely to see the frost earlier due to cooler air settling here first before the urban areas.

As we move further into Autumn, if you have outdoor plants exposed to the elements, be sure to keep a close eye on temperatures so that frost damage does not occur.