Known as peak day, last Wednesday was the day milk production for the season peaked, with flows through the co-operative's 26 processing sites three million litres more than on last year's peak day.
The company would not release regional statistics, saying they were commercially sensitive, but data from producer body Dairy NZ shows that in the 2008-09 season, the country's 11,618 dairy herds produced 16 billion litres of milk, 50% more than was produced in 1998-99.
Peak production day always occurs at this time of the year, a combination of cows reaching full production, the end of calving and pasture quality and quantity being at its best.
Taieri sharemilkers Cam and Anna Edgecombe said a warm and dry October had turned their season around.
"It was a difficult August-September; it was certainly trying, but in October there has been a big turnaround," Mr Edgecombe said.
They are in their first season milking 450 cows on 150ha at Berwick for Mike and Philippa Lord, and Mr Edgecombe said their season peak production was 10,500 litres a day, but had stabilised at 10,000 litres a day with continued favourable weather.
Farmers are paid in kilograms of milk solids, and an average Otago dairy herd of 514 cows will produce 185,144kg of milk solids (kg/ms) in a season, or 2.17 million litres.
That equates to each cow averaging 374 kg/ms a season.
Fonterra has forecast paying farmers between $7 and $7.10 a kg/ms this season, which means an average cow will earn a farmer about $2600 this season.
Fonterra's trade and operations managing director, Gary Romano, said wet early spring weather in Waikato and Taranaki and snow in Otago and Southland had been followed by warm weather, which had driven a sharp increase in milk production.
Overall, milk production through Fonterra was ahead of this time last year, which ended with production of 1286 million kg/ms, but he warned with just a third of the season gone, that could change.