How Temperatures, Daylight Fall From Late September to Late December

Chris Dolce and Brian Donegan
Published: September 20,2016
Fall 2016 officially arrives Thursday at 10:21 a.m. EDT with the autumnal equinox. Unlike summer, which is fairly consistent from start to finish, fall is a time of rapid change across the country.
The first of these many changes highlighted below might make you shiver.
(MORE: Bad News For Fall Lovers: Peak Summer Temperatures Coming Later)

First Freeze of the Season

One of the first things we look for in the fall is the first frost and freeze of the season, killing or sending into dormancy the beautiful vegetation you admired all summer long.

For some locations along the Canadian border, and in the higher terrain of the West, the first freeze typically arrives by mid-September.
The table below shows the earliest first freeze dates and the average first freeze for select cities in each region of the United States.

City	Earliest First Freeze	Avg. First Freeze
Chicago	Sept. 22	Oct. 13
Minneapolis	Sept. 3	Oct. 9
New York	Oct. 15	Nov. 20
Pittsburgh	Sept. 19	Oct. 18
Atlanta	Oct. 11	Nov. 17
Dallas	Oct. 22	Nov. 22
Denver	Sept. 8	Oct. 3
Seattle	Oct. 18	Nov. 16

Cities in the South may not see the first freeze until November, though a frost is very possible before then.
(MORE: A Handy Guide to When Your First Freeze Typically Arrives)
A few cities in the Lower 48 states, including International Falls, Minnesota, and Grand Forks, North Dakota, have recorded a freeze in every month of the year.

First Flakes

Fall marks the return of snow to many forecasts across the country.
For snow lovers, the potential of seeing the first glimpses of wintry precipitation makes fall an exciting time of year. Others may sigh and say, "Ugh, here we go again – a long season of shoveling is ahead."
(MORE: First Accumulating Snow Can Happen Just Weeks From Now)

City	Earliest Measurable Snow	Average First Measurable Snow
Chicago	Oct. 12	Nov. 19
Minneapolis	Sept. 24	Nov. 3
New York	Oct. 21	Dec. 15
Pittsburgh	Oct. 18	Nov. 15
Denver	Sept. 3	Oct. 17
Salt Lake City	Sept. 17	Nov. 4

For those in the Great Lakes, the lake-effect snow machine begins to crank up as cooler air rides over the relatively warmer waters of the lakes. This is particularly the case in November.
Snowstorms along the Front Range of the Rockies are something that can happen very early in fall. Denver averages about 4 inches of snow in October and 9 inches in November.
Many cities along the northern tier of the country see their first measurable snowfall before the winter solstice arrives.

'Fall'ing Temperatures

We all know that temperatures trend cooler and cooler across the country from the start to the end of fall. Many of us will be swapping that light jacket in the morning for a heavier coat in the months ahead.

Our average temperature maps contrasting September (above) to December (below) show that highs in many cities of the Midwest and Northeast fall from the 50s and 60s to the chilly 20s, 30s and 40s by the time the winter solstice rolls around. Highs in the 50s and 60s replace 70s and 80s in the South.
(MAPS: Average Highs/Lows)
Here's a few examples from each region:
Chicago: Average high of 72 degrees on Sept. 22 drops to 33 degrees by Dec. 20.
New York: Average high falls from 73 degrees in late September to 42 degrees by Dec. 20.
Atlanta: Average high drops off from near 80 degrees in late September to the low 50s in late December.
Seattle: Average highs trend downward from about 69 degrees in late September to the mid-40s in December.

Length of Daylight Shortens Quickly

According to the National Weather Service in Binghamton, New York, the 17-day period from Sept. 16 through Oct. 2 is when parts of the northern states lose more than two and a half minutes of daylight per day, the fastest rate all year.
The sun angle is getting lower in the sky as the sun's most direct rays shift from over the equator on the autumnal equinox to the Southern Hemisphere.
(MORE: When Does Your City See Peak Fall Color?)
Here's a table comparing the sunset times on Sept. 22 and Dec. 21, the first day of winter.

City	Sept. 22 Sunset	Dec. 21 Sunset
Chicago	6:47 p.m.	4:23 p.m.
Minneapolis	7:09 p.m.	4:35 p.m.
New York	6:52 p.m.	4:32 p.m.
Pittsburgh	7:16 p.m.	4:57 p.m.
Atlanta	7:34 p.m.	5:33 p.m.
Dallas	7:23 p.m.	5:25 p.m.
Denver	6:56 p.m.	4:39 p.m.
Seattle	7:06 p.m.	4:20 p.m.

Most places will generally see their sunset two to two-and-a-half hours earlier three months from now. However, we really aren't losing that much daylight since we'll turn the clocks back an hour on Nov. 6.
If we didn't have the holidays to look forward to in late December, it would certainly be a depressing time of year with darkness coming before 5 p.m. in many places.