That means most farmers will be comfortably in the black after the near debilitating slump of 2015 and 2016, which saw a rapid escalation of farm debt.
Chairman John Wilson said the strong opening milk price forecast for 2018/19 would be welcome news for the co-operative's farmers.
"What we are seeing is a continued positive global supply and demand picture which gives us the confidence to increase our current forecast farmgate milk price into the new season," he said.
"Demand is expected to remain strong – especially from China and for butter and anhydrous milk fat," he said.
But in a conference call, he said volatility in milk prices had once again made life difficult.
"The challenge with that is that we are getting this ongoing volatility in our earnings, which of course causes much frustration for our unit holders and our shareholders, so we have therefore lowered our earnings forecast [to] 25-30c a share [and] our dividend to 15 to 20c a share," Wilson said.
However, the total forecast cash payout for farmers increased to $6.90 to $6.95 per kg - the third highest payout this decade.
Chief executive Theo Spierings said the earnings challenge that came with the higher milk price was compounded by the timing of the increase.
"There is always a natural lag in being able to pass through an increase in our input costs. But this increase has been both rapid and late in the year, making it difficult for these higher costs to flow through into our sales for this financial year," he said.
"Against this backdrop, we can see our sales margins are not where they need to be at this point in the year to achieve our original earnings forecast."
In its third quarter business update, Fonterra said its revenue of $14.8 billion for the first nine months of 2017/18, was up 7 per cent on the same period last year.
In the first half, the co-op felt the impact of the record low inventory followed by the low spring milk collections in New Zealand due to difficult weather conditions, Spierings said.
Economists were circumspect about the prospects for the coming season.
"There is more uncertainty about the outlook for the 2018/19 milk price this early in the season, and we would treat it with more caution," said Westpac senior economist Anne Boniface.
"However, a third consecutive season where most dairy farmers [are] in positive cash flow territory should come as good news for New Zealand's agriculture sector," she said.
ASB Bank rural economist Nathan Penny said Fonterra's milk price upgrades were more bullish than expected.
"For now though, this bullishness is being tempered by mycoplasma bovis concerns. As a result, farmers are unlikely to act on the strong milk price outlook and their spending and investment plans are likely to subdued until mycoplasma bovis concerns recede," Penny said.
Federated Farmers dairy chairman Chris Lewis said it was important that opening milk price forecasts erred on the conservative side, because they can always be increased as the season progresses.
"It's a hard conversation to take it down, so hopefully they have got their numbers right and that it will stand the test of time."
The Ministry for Primary Industries is expected to announce next week as to whether it will attempt to eradicate Mycoplasma bovis, which first emerged in the South Island last year, or to move to some form of management over the long term.
