Add the matcha powder to a measuring cup or small bowl.
Pour in 1 to 2 tablespoons of hot water.
Whisk vigorously until the matcha dissolves completely and forms a smooth paste.
Add the remaining 1 cup of warm water and whisk until fully combined.
Place the mixture in the refrigerator or freezer for about 15 minutes to chill.
Fill two serving glasses with ice.
Pour milk into each glass until approximately three-quarters full.
If desired, add sweetener such as simple syrup, honey, or maple syrup.
Slowly pour the chilled matcha mixture over the milk.
Stir before serving and enjoy your homemade Iced Matcha Latte.