Sussex and Glamorgan will play the only match of the 2019 Vitality Blast on August 6, at County Ground, Hove.
August 4 will feature four Vitality Blast matches, at New Road, Headingley, Bristol, and Richmond.
The top team of North Group will be fighting the fifth in the race on August 3.
There are eight matches of Vitality Blast 2019 scheduled for August 2.
As Middlesex and Kent battle for the top spot, Glamorgan will hope to push themselves off the bottom of the table.
Worcestershire will hope to keep pressure in pursuit of the top spot while Leicestershire looks to move out of the bottom.
In a South Division clash, Surrey will host Kent Spitfires at The Oval on July 30.
Sunday will feature three Vitality matches: Derbyshire Falcons vs Lancashire Lightning, Northamptonshire Steelbacks vs Yorkshire Vikings, and Worcestershire Rapids vs Durham Jets.
Saturday will feature two Vitality Blast 2019 matches, at Trent Bridge and Chelmsford.
July 26 will feature eight matches, at Old Trafford, Grace Road, Northampton, Cardiff, Taunton, Derby, Canterbury, and Hove.