April showers bring doubleheaders — but usually later in the season.

In this case, the Mets and Giants had little choice but to reschedule immediately. With the Giants scheduled only to visit Citi Field this week, Monday’s ugly forecast translated to two games on Tuesday.

The teams will play a single-admission doubleheader beginning at 3:10 p.m., with Tylor Megill set to face Alex Cobb in the first game. In the nightcap, the Giants are set to start Logan Webb against Max Scherzer.

After two seasons of seven-inning doubleheaders MLB has reverted to the traditional nine innings for each game.

Last season the Mets played 14 doubleheaders. They went 18-10 in those games.

Scherzer’s appearance will be his home debut with the Mets. The right-hander opened his Mets career with starts in Washington and Philadelphia.

Luis Guillorme, whose beard has become a trademark of sorts, was clean shaven on Monday. The infielder last went beardless in 2020.

The Mets have nine stolen bases through 10 games. Last season the Mets didn’t steal their ninth base until their 32nd game. Entering Monday the Mets were tied for second in the major leagues in stolen bases this season. In spring training, Francisco Lindor told The Post he would like to see the team surpass 100 stolen bases this season. In 2021, the Mets stole 54 bases. The Mets have since added Starling Marte, who led MLB with 47 stolen bases last season.

Pete Alonso moved alone into 13th place on the Mets’ all-time home run list with his blast against the Diamondbacks on Sunday. Alonso, who has homered 109 times in his career, moved ahead of Jose Reyes. Next up are Ed Kranepool (118) and Edgardo Alfonzo (120). Alonso’s 47 homers at Citi Field are fourth all-time by a Mets player. Lucas Duda is the leader with 71.

Lindor has reached base safely in all 10 games this season. He is 9-for-33 (.273) at the plate with three homers, seven RBIs and nine walks. He owns a .442 on-base percentage and .606 slugging percentage.