On Jan. 20, 2017, President Trump took the oath of office, pledging in his inaugural address to embark on a strategy of "America first." Here are key moments from that speech. (Sarah Parnass/The Washington Post)

It's raining in Washington today — or, at least, it's rainy. It's not cold, really, at 45 degrees, but there are certainly reasons one might rather stay inside than, say, head to the Mall to watch an hour-long outdoor event.

Perhaps that's one reason that the crowd in attendance at Donald Trump's inauguration seems a bit more sparse than in years past. Or perhaps it actually is more sparse — particularly in comparison to the first inauguration of Barack Obama in 2009.

It can be tricky to evaluate attendance at events based solely on photos. Perspective matters, as does the time at which the photos were taken. Take the images below, from the inaugurations in 2009 and 2017.

2009


Crowds gather on the Mall for the swearing-in ceremony of President-elect Barack Obama. (The Washington Post)

2017


Crowd gather for the inauguration of President-elect Donald Trump. (Carlos Barria/Reuters)

The latter certainly seems to include fewer people — but when was it taken?

This tweet, from the Boston Globe's Matt Viser, offers a different perspective.

That ABC News screen capture was from a bit before the event itself. Below is a still from CNN, taken only a few minutes before Trump took the oath of office. The crowd looks similarly sparse.


Side-by-side, from our Matt Callahan.


Washington's public transit system offered its own assessment of how the crowds compared.

Put visually:


So we can assume that Trump's inauguration was not quite as popular as Obama's.

How does it stack up to other presidents?

Again, comparisons can be tricky. Here are similar scenes from 2001, when George W. Bush was inaugurated, and 1993, Bill Clinton's day.

2001


(Still from CNN)

1993


(National Archives/Smithsonian)

Again: Hard to tell!

To a large extent, such comparisons are simply a form of partisan competitiveness. It would, however, be very on-brand for Trump to assert that the crowd at his inauguration was one of the largest of all time. (He's already claimed that the day would see “unbelievable, perhaps record-setting turnout.") Or perhaps he will blame the weather for lower-than-expected turnout. Possible.

Though in 2009, the temperature was four degrees below freezing — one of the coldest inaugurations on record. Perhaps the larger crowds that year were simply an effort to utilize body heat.

In at least one sense, Trump seems to acknowledge the impressive size Obama enjoyed eight years ago.

Update: Prof. Kenneth Still, who has helped us with crowd counts in the past, told the New York Times that he estimated the 2017 crowd at about a third the size of Obama's in 2009. Dan Gross, who worked for Obama's 2012 inauguration, estimated Friday's crowd at 250,000, compared to 1.8 million in 2009.