At least, that’s the reason that’s being given by Trump:

The weather forecast for Washington, D.C., with the windchill factor, could take temperatures into severe record lows. There is an Arctic blast sweeping the Country. I don’t want to see people hurt, or injured, in any way. It is dangerous conditions for the tens of thousands of Law Enforcement, First Responders, Police K9s and even horses, and hundreds of thousands of supporters that will be outside for many hours on the 20th (In any event, if you decide to come, dress warmly!).

Therefore, I have ordered the Inauguration Address, in addition to prayers and other speeches, to be delivered in the United States Capitol Rotunda, as was used by Ronald Reagan in 1985, also because of very cold weather.

When I look up the weather forecast for DC on Monday, it says 24 degrees with winds between 10 and 20 miles per hour. That’s indeed cold, and although for New Englanders it’s not at all unusual, it’s bitter for DC. I suspect, however, that moving the ceremony inside also makes security much easier. I’ve been worried about security for that day, and so I prefer this solution.

Here are the cold weather precedents:

The last time the ceremony was moved inside was for Ronald Reagan in 1985, also due to extremely cold temperatures. It was 7 degrees with some stiff winds topping 30 mph, which put the wind chills well below zero.

Wow. That is much colder. More:

Historically, early presidential inaugurations were often held indoors within the Capitol, explained FOX News Senior Congressional Correspondent Chad Pergram to FOX Weather, noting that President Thomas Jefferson’s inauguration followed this tradition.

Pergram further explained that President James Monroe initiated the practice of holding inaugurations outdoors. This shift occurred after the War of 1812, during which the British forces burned the Capitol building.

In addition, every US schoolkid knows – or used to know; I have no idea what they learn these days – that President William Henry Harrison apparently contracted pneumonia because of standing in the cold and wet to deliver his inauguration address in 1841, and died a month later. Although many people on the left would love for Trump to follow that particular precedent, he’s not taking that chance.

The first inauguration I can recall was that of President Kennedy. I was a child at the time, and I watched it in black-and-white on TV, and I remember it as very cold. Looking it up now, I see that was indeed the case:

In 1961, when John F Kennedy was sworn in, temperatures didn’t get past 22F (-5C) in the afternoon and there was 8 inches (20cm) of snow on the ground.

Not as much wind, though? More on the weather here:

The U.S. Army Corps of Engineers was put in charge of clearing the streets during the evening and morning before the inauguration, and were assisted by more than 1,000 District of Columbia employees and 1,700 Boy Scouts. This task force employed hundreds of dump trucks, front-end loaders, sanders, plows, rotaries, and flamethrowers to clear the route. Over 1,400 cars which had been stranded due to the conditions and lack of fuel had to be removed from the parade route along Pennsylvania Avenue.

I see from footage of JFK’s inauguration that he seems to have worn a topcoat without a scarf. And then there’s the bit about the top hat and JFK:

NOTE: Does getting chilled predispose a person to coming down with a cold or pneumonia? Well, maybe a little tiny bit:

“If you’re a little bit colder outside, your body’s immune system may just drop a little bit because it’s spending extra effort to keep you warm. That’s not with everybody, but, in some cases, it may predispose you to a cold,” says Dr. Bracamonte.

But, he says, the cold weather itself doesn’t cause the common cold. However, as winter temps dip down, the chances of spreading a respiratory virus go up because more time is spent indoors with others.