The hosts completed the first innings of their final with Netherfield before the rain came as Ben Simm’s men closed on 164-8 from their 20 overs.
The run up to the marquee event had been beset by problems with both Blackpool and Darwen pulling out as it clashed with their Lancashire Cricket Board Knockout third round ties.
It meant an action-packed day of two semi-finals and a final between the four group winners was reduced to a straight final between Lancaster and Netherfield.
The sides will now try again this Sunday, July 12, on the reserve day.
It remains unclear whether Blackpool and Darwen’s participation in finals day will be reconsidered.
The day before, Saturday, July 11, Lancaster will travel to Fleetwood in the Northern Premier League having had their week off from league competition last Saturday.