On the Monday morning after Daylight Saving Time kicks in, we’re both groggier and happier—or, at least, that’s what Facebook says.

The insight comes from the company’s Data Science team, which works with proprietary information gleamed from the statuses written by millions of Facebook users. They were published in a blog post today.

On the Monday morning after Daylight Saving Time (DST) began this year, 25 percent more Americans told Facebook they were tired than would do the same on a usual Monday. Likewise, instances of “sleepy” and “exhausted” were both up.

By the afternoon, however, people reported their sleepiness at normal rates. You can see that on the graph above—“feeling tired” spikes in the morning but falls in the afternoon.

Those numbers varied from state to state. They were highest in the middle of the country to the midwest—Delaware’s use of “feeling tired” increased some 231 percent. Arizona doesn’t honor DST, but even it saw a rise in sleepiness, too. Members of the Data Science team wonder whether that’s because Arizonans were traveling.

Here’s what that looks like on a map. According to Facebook, it “shows the effect in every geographical area (regions of the map have similar population), with a darker blue indicating a larger increase in ‘feeling tired’ over the previous Monday morning.”

Facebook

But there’s an upside to all this exhaustion. Switching to DST doesn’t only mean we lose an hour of sleep; it also means we see more sunlight in the afternoon. And that, it seems, makes us all feel better:

On the Monday following DST, we see +21% increased usage of "wonderful", and +19% increased usage of "great" compared to the previous Monday. Meanwhile, "annoyed" is down 14 percent and "bored" is down 12 percent. Even the generic macro-feelings of happy (+5.7%) and sad (-4.8%) follow these patterns.

These results seem regional: Facebook’s team writes that the mood of Facebook statuses appears to increase most in the northern states, especially in the afternoon, after people get out of work and see the sun. And, while folks are tired on Monday, they say, that exhaustion is gone by Thursday.