With its cold weather and short days, winter is upon us. Here are a few things that might surprise you about this chilly season…

1.     Winter just started.

Winter doesn’t begin until the winter solstice of each year, which is usually December 20th or 21st. The past year, winter began on December 21st (at 5:44 am, to be exact). Winter ends on March 20th this year.

2.     You’re more likely to die in winter than in summer.

About 20 times more deaths occur in winter than in summer, as discovered by a recent international study. This is largely due to the greater chance of a stroke or heart attack in cold weather.

3.     The holidays were much warmer last year.

It was 72 °F in Bryn Mawr on December 24th last year. This year, it was 45 °F.

4.     You have 30 hours to get your sidewalk clear.

If you have a sidewalk in front of your home, township policy states that you have 30 hours after it stops snowing to shovel it.

5.     Salt lowers water’s freezing point.

The reason salt is thrown on icy roads is that it lowers water’s freezing point. This makes it easier for a thin layer of water on top of the ice to melt the ice. Salt helps prevent water molecules from clustering together into ice, but some salt is better at this than others. Table salt, or sodium chloride, is generally not used on roads because it is not as effective as calcium chloride. Calcium chloride breaks into three ions in water while table salt breaks into two.

6.     Salt is harmful to the environment.

After all that salt is dumped on the ground to melt ice, it has to go somewhere. The salt ions enter groundwater and other bodies of water. The ions kill plants and aquatic animals, but alternatives to salt are currently too expensive for most cities.

7.     It takes a lot of salt to clear the roads.

The Lower Merion township states that it uses 500 lbs of salt per linear mile on roads. Not only salt is applied on roads, but limestone and granite are tossed out as well. Limestone and granite serve as anti-skid materials.

8.     December 23rd was a very busy shopping day.

In 2016, the busiest shopping day was December 23rd, when people bought last-minute holiday gifts. About 156 million Americans shopped on that day.

9.     Your car is less efficient in the cold.

Cold weather affects many of a car’s functions and causes a car to go fewer miles per gallon than it goes in warm weather. Colder temperatures cause greater friction between car parts, meaning more energy is required to move the parts. In addition, the air in tires condenses in cold weather. The tires cannot roll as smoothly when they are slightly deflated. On highways, mileage can be affected by the density of the air. Cold air is denser than warm air, so it takes more energy for the car to move through cold air.

Winter may be frosty, but at least there are some fascinating things to learn about the season!