"A cold front came up and joined a system with the Tasman and then formed a low out on the coast," Kozyniak said.
The climate scientist said there was also significant rainfall in the last two days of the month.
The Heretaunga Plains received 160 per cent of the average rainfall this month, followed by the Ruahines at 137 per cent and the Ruataniwha Plains at 136 per cent.
Other areas followed closely behind with Waikaremoana and the Kawekas both receiving 129 per cent and Tangoio 121 per cent.
Northern Hawke's bay had the lowest amount of rainfall with 103 per cent.
The region had 55 lightning strikes, mostly on the 9th and 10th.
Federated Farmers Hawke's Bay president Will Foley said the month's rainfall meant the region's farmers were well-prepared for the winter ahead.
"There's a lot of supplement feed being sold to Manawatu and Taranaki because they've had a really tough season over there and they've needed that extra feed.
"I don't know whether that means there's going to be less around here for the winter but in terms of actual grass and feed levels on the ground I think everyone is pretty well set up."
While other regions in the country had faced serious weather issues in recent years, he said Hawke's Bay had enjoyed a "good run".
"There's been those odd heavy rain events but on average across the region I'd like to think Hawke's Bay hasn't been too bad, particularly referring to no major droughts which can hammer us.
"The events we have had have been more localised and have been quite serious for those affected but generally quite localised down to half a dozen farmers at the most but nothing region-wide."
Foley couldn't see any issues cropping up for farmers in the near future and said the wet summer and spring had been a contributing factor to that.
"It's certainly not causing any issues. Most people feel pretty comfortable coming through the wetter than normal summer they had so most farmers are pretty comfortable in the space that they're in. There's good feed levels and stock are in good conditions."
