House members walk down the east front of the U.S. Capitol building to speak with supporters on June 23, 2016. (Allison Shelley/Getty Images)

It doesn’t take visitors to Washington very long to learn two things. First, that when Congress is in session, there’s often not that much going on on the floor of the House and Senate. And second, that Congress very often isn’t in session.

President Trump has been in Washington for almost 16 months. By now, he is familiar enough with how Congress works that he finds it necessary to tweet things like this:

The August break, as you might expect, covers most of August. But Trump, worried enough about how things go at the other end of Pennsylvania Avenue, already feels as though he has to tell them to buckle down and do some work. It’s like a teacher telling his class in March that there are still some things that need to get done before school’s out for the summer. How far are we from that August recess? Congress still has two more recesses before that recess:  Memorial Day and the Fourth of July.

We’ve crunched the numbers before and noted that Congress loves to not be in session. Ostensibly, this is because members of Congress are doing important work in their districts, and also, you know, they work all the time, so it’s not fair to use being in session as a measure of how much they work. Fine. But that’s something of a cop-out, given that obviously it’s not as if Congress is always working when it’s not in session. And one way we know that is by looking at when they are and aren’t in session.

Here, for example, is a heat map of the average number of weekdays since 1975 (in the case of the House) or 1978 (for the Senate) that each chamber has been in session. The darker the blue, the more of those weekdays each chamber has been working (in our narrow sense of the term). This chart includes only weekdays, mind you, starting with the first weekday on or after Jan. 1.

We’ve identified certain periods of the year when Congress usually isn’t in session. The August break stands out.

But notice that we also highlighted the period of October and early November during years in which there are federal elections. Weirdly, Congress isn’t in session much during that period. They are either (1) hard at work in their districts, serving their constituents, or (2) campaigning. You may try to guess which. I will note, though, that it is a remarkable feature of our political system that members of Congress get to take time off their jobs to persuade people to let them keep their jobs.

Imagine if you were at risk of being fired and you asked your boss for a month off to prepare an argument for why you shouldn’t be fired.

It’s not just a visual trick that makes it look as though the House and Senate are in session less during election years. Here’s the average number of weekdays each chamber has been in session over the period for which we have data (which comes from the chambers’ websites).

You’ll notice that the House is in session on a lower percentage of weekdays than the Senate. In part, that’s because the Senate got into a fun habit of calling a pro forma session to prevent presidents from making a recess appointment. (This goes back to our original point: Even when they’re in session, it doesn’t mean that they’re doing a lot of legislating.)

But it’s also historically the case that the House is in session for a lower percentage of weekdays, a tradition that holds true in 2018. Per each chamber’s schedule, the Senate is in session more this year, too — not hard to accomplish when the House’s official schedule has them in session for precisely zero five-day weeks.

In fact, since 1975, the House has been in session on fewer than half of weekdays during election years. If you visited the House on a random day in any even-numbered year of the past 40, the odds were good that the body wouldn’t be in session.

Many of these weekdays that the House and Senate aren’t in session, it’s for a good reason. There are lots of federal holidays, for example, some of which are always on weekdays and some of which are on weekdays 71 percent of the time. It’s just that taking off a couple of months each year strikes newcomers as perhaps excessive.

Which is partly why Trump is annoyed that they might go on recess for a month without getting everything done that he wants. But we will note that Trump is not entirely averse to taking time off.

Since he was inaugurated, Trump has played golf 23 times on weekdays, mostly (but not exclusively) when he was on vacation. He has managed to play a round of golf once every 5.1 days, by our analysis, and has visited one of his private businesses’ facilities once every 3.1 days. (See chart below.)

Trump being out of the White House, like Congress being away from Capitol Hill, doesn’t mean that he is not working. But, like Congress, he’s happy to imply that he’s working long hours each day even while he regularly escapes to the golf course or tweets about what he’s watching on Fox News.

If you were curious, by the way, the House’s official calendar indicates that it is not in session Monday. Hopefully, some of the members can take time from their busy working-away-from-D.C. schedules and read this article.