Last week's rain was likely to have evaporated before it could do any good, Mr Rowse said.
"If the heat keeps on we'll have to look at the herd a bit harder and get the numbers down a bit more quickly ... it's hard to have a crystal ball to see what the weather is going to do, but it doesn't look promising."
Allan Renall, who has dairy farms at Parkvale and Gladstone, said he is feeding his herd silage and irrigating his paddocks and was considering destocking.
"It's bloody dry."
"It's January in Wairarapa and we expect it to be like that but the pinch is starting to show a bit - we haven't been able to draw from the stream since before Christmas."
With Fonterra's forecast payout reduced to $4.70 a kilogram for milk solids, it was time to cut back on spending, Mr Renall said. "The cash flow is starting to bite with the down turn in the payout and the milk flow dropping."
Although last week's rain saved his barley and maize crops, Mr Renall was hopeful this week would bring several days of rain.
"We've got to battle on until it rains. We usually find that if we get a big dry we get a good autumn."
DairyNZ's general manager of extension, Craig McBeth, said the organisation is closely monitoring the soil moisture for farmers having a dry summer on top of a low seasonal milk price.
"It is already severely dry in parts of Canterbury and North Otago and farmers there are facing serious measures with some irrigation restrictions now in place. The south of the Wairarapa is also very dry.
"We need to see some rain soon to reduce the risk of a normal dry summer turning into something more serious."
Federated Farmers Wairarapa dairy representative Chris Engel said the lack of substantial rain and the low payout would be putting pressure on farmers, particularly new farmers.
"It could be a great concern that it's compounding the pay out. Suppose someone has just bought a farm on $8.50 a kg and then within half a year it turns dry.
"The thing that has to be of concern [is] ... the mental health of the farmers - it can be a major issue.
"I was surprised at the numbers - because of the payout being so low there was quite a few numbers of mental health issues occurring with farmers, and that is to the extent of being fatal."