Everything seems to have turned around for the Mets in the second half of this season. Once a weakness, the team's offense has become a strength. The thrilling starting pitchers have become a point of some concern. The cautious front office went out and made a huge acquisition along with several smaller ones. Add this to the list: The Mets are now playing better away than they are at home.
Before the All-Star Break, the Mets' record was being kept afloat by their dominance at Citi Field, with a 32-14 home record that made up for a 15-28 record in opposing parks, putting them five games over .500 at the break. Since the break, the Mets have made obvious improvements across the board, but their 23-9 second-half record in opposing parks is a huge shift from their performance in the first half.
There are plenty of reasons for this drastic change. The Mets are a better team all around since the break, with a dynamic offense and a strengthened bullpen. Then again, maybe the home/away split of the first half was exaggerated to begin with. Yes, the Mets had some bad losses ion the road, dropping a series to the Brewers and getting swept by the Braves, but they also played a lot of tough away games, including seven total against the Pirates and Cubs, who eventually swept the Mets at Citi Field just like they did in their own parks.
Moreover, most teams are usually better at home in general; the home team wins around 54% of the time. That means the road team wins 46% of the time, and with a bit of bad luck that number could drop, particular in a relatively small number of games. In other words, the Mets probably weren't a bad road team—or a good home team—they just lost a few more games on the road than they were expected to.