Another month of baseball is in the books, and there are loads of surprises so far here in the 2015 season. The Astros and Twins are in first place, while the Red Sox and the Athletics are in last.

Yeah, you didn't see that coming.

But there are also a lot of things that have gone along just as they should. The Phillies, Brewers and Rockies are all in last. The Nationals, Cardinals and Dodgers are all in first. And the birds are in the sky and the sun shining down.

The month of May was an interesting month with some well-known names at the top of the individual and team statistical leaderboards. Let's take a look at who had the best months of May, by the numbers.

All the talk this month has been about the Nationals' Bryce Harper (more on him in a moment), but the man who had the best overall month plays for the Cleveland Indians, Jason Kipnis. His 3.1 fWAR led all Major Leaguers, with Harper second, a good half-run behind. Josh Donaldson also had a terrific month, tying with Todd Frazier and Paul Goldschmidt for the third-highest fWAR in the month of May.

Looking at the home run totals, Harper's 13 are far and away the most, and his slash line of .360/.495/.884 with 28 RBIs and 22 walks all but assure him of winning National League Player of the Month. Most of the other names atop the leaderboard are not unexpected, with the possible exception of Joc Pederson, the Dodgers' rookie center fielder, who hit nine.

Weighted runs created (wRC+) is a stat that determines if a batter creates runs below or above a league average player, with 100 being league average. There were not a lot of surprises on this list, either. Kipnis will likely win the American League Player of the Month award, Nelson Cruz continues to mash and the surprising season of Oakland's catcher Stephen Vogt continues unabated.

Above are the players who struck out the most last month. Souza has had an interesting season, with a low batting average (.238), but a decent on-base percentage (.333) and a good slugging percentage (.475) with a wRC+ of 133, 10 home runs, and an fWAR of 1.1 (season totals). The rest of the names on this list are more of the usual suspects, some of them the most intriguing young hitters in the game, like Chicago's Bryant and Russell.

Harper continues to walk at a much higher rate than at any time in his career. Teams are clearly becoming more cautious when pitching to him, which is probably a smart thing, given the fact he is a maniac at the plate right now. If Harper maintains his current plate discipline, he should be able to maintain this rate all season.

Who were the best pitchers in May? It's no surprise that the Nats' Max Scherzer tops the list in terms of fWAR. Last year's AL Cy Young Award winner, Corey Kluber, is fully back, ranking second among all pitchers. One surprising name is Oakland's Jesse Chavez, who according to fWAR had the third-best month among all Major League starters.

Expected Fielding Independent Pitching (xFIP) is a stat that takes into account all the areas that a pitcher can control (walks, strikeouts, and home runs), and computes it into an ERA-like number that projects how a pitcher is expected to do for the rest of the season. Kluber is tops on this list, with New York's deGrom second. Not a lot of surprises here, either.

Finally, we'll look at some team numbers. Which teams had the best pitching staffs in the month of May?

The Cardinals put together the lowest ERA last month at 2.94, that includes both starters and relievers. One of the reasons the Rays have been able to hang in the AL East (other than the other teams in the division being pretty mediocre), is a pitching staff that had a solid month as well.

According to xFIP, Cleveland's high strikeout rate has made them the darlings of the sabermetrics world. They've been unlucky on balls in play, which is one of the reasons they are at the top of this list. And look out for that Astros staff, especially the bullpen, who one year after being the worst in baseball is now among the very best.

The Dodgers were led by Justin Turner, who put up an fWAR of 1.3 last month, followed by Yasmani Grandal and Pederson at 1.1. The Blue Jays had a solid month at the plate, as did the Giants, Indians and Royals.

And with weighted on base average, the Dodgers lead the pack here as well at .338, with Toronto right behind them here too.

Interestingly, the team with the best record in the American League in May, the Minnesota Twins at 20-7, were nowhere to be found on any of the individual or team lists. It just goes to show, you can't predict baseball.