The biggest surprise on a day of heavy showers and blustery wind was that three of the four scheduled top-flight games reached a conclusion, only the meeting of East Kilbride and Drumpellier being washed out completely.
Batting first, Ayr did well to reach 166-6 from 30.5 overs in what was both a rain-interrupted and truncated innings. After being set a revised target of 132 from 20 overs West were never in the hunt and were all out in the final over, having stuttered to 81.
"It was a great effort to get the game on considering the weather and a great performance from us," said Andi McElnea, the Ayr captain. "We were ruthless in the second half with our bowling."
There were some exceptional individual performances, notably from McElnea and his younger brother, Scott. While the latter is better known for his pace bowling, it was his top-score of 35 which caught the eye at Hamilton Crescent, an effort matched by Steve Liburd. Young Shujaa Khan's unbeaten 25 was also important as Ayr recovered from the loss of early wickets to post a challenging total.
The McElnea brothers then combined to claim eight of the West wickets, Scott taking 3-10 but being outshone by the skipper, who again demonstrated his growing prowess as a spinner with 5-16.
Ayr will be crowned champions next week providing they take at least four points from their home encounter with Clydesdale, a side which kept their slender title hopes alive by beating Renfrew. In another rain-reduced affair, Paddy Barbour's hard-hitting 47 put Clydesdale on course for a crucial seven-wicket win.
The Glasgow club, Scottish Cup finalists and still on course for the National T20 Cup final, could still pip Ayr to the title but it would require them to win their final two games and the unbeaten league leaders to lose both theirs.
Outgoing champions Uddingston suffered a heavy defeat by Dumfries as Pat Druce's five wickets caused the visitors to be dismissed for just 72 in 29.5 overs. Alan Davidson then stroked 36no as Dumfries cruised to a nine-wicket victory.