CREATE TABLE table_62370 ("Date" TEXT, "Series" TEXT, "Circuit" TEXT, "City / State" TEXT, "Winner" TEXT, "Team" TEXT)

On which date did the Winfield Triple Challenge series take place?
SELECT "Date" FROM table_62370 WHERE "Series" = 'winfield triple challenge'
SELECT "Date" FROM "table_62370" WHERE "Series" = 'winfield triple challenge'