4 game series @ the New York Yankees: May 20-23
With the New York Yankees getting Juan Soto and Aaron Judge finally healthy they are making a case for being the best team in AL East with the Baltimore Orioles. They are only going to get better with their ace Gerrit Cole set to return by the end of May, but the Mariners should miss him. The Yankees sit at 19-12 and second in the AL East.
3 game series @ the Washington Nationals: May 24-26
Mariner's end their long road trip against the revitalized Jesse Winker and the 14-15 Washington Nationals. The Nationals are doing a lot better than most people expected but I still think the Mariners will take care of them and get a series win.
First game of 3 game series vs Los Angeles Angels of Anaheim: May 31
The Angels are back to their same old selves, Shoehei Ohtani is gone, Mike Trout and Anthony Rendon are hurt, and the Angels don't have any pitching. The Angels are 11-19 and shouldn't be much of a problem for the Mariners.
Prediction for the month of May
The Mariners will play 15 games against teams over .500 and 14 games against teams under .500, with seven of the games against the under .500 teams being the Astros. So this month could test the Mariners. My prediction is the Mariners go 17-12 for the month of May. I believe the Mariners hitting will come around this month and especially Julio Rodriguez.