It was not the way they would have wanted to clinch the title but there can be no doubting they are worthy champions, with four more wins than any other side, only two defeats and 40 points ahead of nearest rivals Appleby Frodingham with three games to go.
Thornes looked on course for another victory when Jared Warner (53) and Akila Isanka (42) put on 70 for the fifth wicket on their way to 193-5 in 33 overs.
Mahmood Rasool picked up two Sheffield Collegiate wickets as the visitors struggled on 6-2 when the game was abandoned.
Doncaster had plenty of reason to curse the weather because they were denied what looked likely to be a victory that would have taken them out of the bottom two.
Luke Townsend (6-34) and Will Street (3-23) shot out Cleethorpes for 120 and Doncaster looked comfortable on 40-1 when the umpires ended the game.
That left them two points behind Treeton whom they meet today. Treeton were on 124-4 at Aston Hall when rain forced them off, Chris Cobb top-scoring with 40.
Mark Cummins (40) and Tom Knight (69) put on 96 in Wickersley’s 188-4 at already relegated Rotherham, while Bilal Anjam (46) was the main contributor to Sheffield & Phoenix United’s 168-7 at Appleby Frodingham.
A century stand between Zohaib Ahmed (88no) and Nathan Firn (51) was the highlight of Barnsley’s 182-5 at Whitley Hall.
Harrogate were the only side to complete their Yorkshire Premier North fixture, beating Sheriff Hutton Bridge by seven wickets and extending their lead at the top to 12 points.
The visitors’ 141 total was reduced by Duckworth Lewis and Matthew Good (45) and Dion Sanson (28no) clinched Harrogate’s victory in 17.2 overs.
Daniel Woods (5-33) and Tom Pringle (4-27) restricted Acomb to 147, and despite losing their first two wickets without scoring, second-placed York were heading for victory with Liam McKendry (43no) and Chris Booth (41no) going well when it was halted.
Yorkshire Academy’s James Logan (5-27) picked up his sixth five-wicket haul and took his tally to 66 in the league, and with Matthew Fisher (4-15) shot out Castleford for 95. David Wainwright, who had top scored with 39, took 3-9 as Academy struggled to 54-4 before the rain intervened.
Driffield captain Danny Broumpton (58no) salvaged his side from 8-4 and, in stands of 71 with Sam Drury (34) and 112 unbeaten with Mark Goddard (57no), took them to 206-7 but was thwarted by the weather with Hull on 72-2.
A half-century from Jake Murphy and quickfire 30 not out from Collis King were the highlights of Dunnington’s 163-6.
An unbeaten century from Adam Waite helped Bradford Premier leaders Pudsey St Lawrence pick up two extra bonus points so they go into the final two games four ahead of Hanging Heaton.
Waite put on 174 with fellow opener Mark Robertshaw (88) and with the help of James Smith (42no) took his side to 246-2 against Cleckheaton, who were 62-1 when it was abandoned.
Hanging Heaton had relegation-threatened Morleyon 160-7 when the rain came.
Bradford & Bingley won the only match to finish, beating Scholes by two wickets. Chasing 151, Bees were 145-5 in which Jack Edgar made 80. But James Stansfield picked up three wickets in six balls on his way to 6-41 before Scott Etherington saw the home side to victory.
Joe Greaves made 42 not out in Pudsey Congs’ 89-4, all four wickets falling to East Bierley’s Tuseif Arshad.
For the second week running the weather claimed the whole of the Huddersfield Premiership but both leading sides in the Aire-Wharfe League claimed wins.
Ishtikhar Hussain took 7-32 as Beckwithshaw skittled Horsforth for 64 on the way to an eight-wicket win. James Davies (5-34) and Jamie Pickering (54no) led Otley to victory against Kirkstall.
Steeton raised hopes they might escape the drop with an eight-run win over fellow strugglers Collingham despite Toby Jacklin’s 5-37 spell.