MetService was yesterday predicting a fine opening day, with high cloud and some northwest breezes, with a deterioration tomorrow to bring some raid, with an ominous "Rain, heavy falls. Southerlies developing" for the big day on Friday.
Mr Mahon's son, CJ, and cousin Paul are used to rolling with whatever the climate throws at them, as there are more than 200 trade exhibitors and organisers of outdoor events such as the equestrian sports, cattle and other animal showing, woodchopping, sheep dog trials and general entertainment.
There are major agricultural attractions throughout, including the launch of the Hawke's Bay Primary Industry Awards, to be attended by Minister of Primary Industries Nathan Guy.
The rides are among 17 brought to Hastings in a huge fleet of vehicles, along with 20 other games amusements, which between them will have up to 100 staff during the show.
For A and P Society and Showgrounds HB general manager Brent Linn it's game-on, despite the weather predictions. "I don't look at the forecast," he said. "I can't do anything about it."