If Taihape and Waimarino don't get regular rain soon farmers will be back where they were in the 2013 drought, Taihape vet Paul Hughes says.
Their situation is worse because they are facing the third dry summer in a row.
In Ohakune, in John and Helen Hammond's first season as dairy farmers, there has been about 130mm of rain since December, with temperatures reaching 40C at times.
"It's one of the hottest summers I have ever known," Mr Hammond said.
Taihape has had only 90mm this year, with much of it in March following Cyclone Pam.
The result has been pasture growth at less than half the normal rate for the time of year.
Both areas have colder inland winters, and have had two light frosts already.
As the temperature cools grass growth will slow. Farmers are desperate for rain in the next six to eight weeks, while the soil is still warm enough to grow enough grass for the winter.
"It's a matter of getting some follow-up rain to get some grass in front of us. We're running out of time for that," Mr Hughes said.
In Taihape, farmers are also starting to struggle for stock water. There's no problem with that in the Waimarino, where streams are still running.
Mr Hammond has been buying in feed for his dairy herd, and said the cows were looking fine.
"If we get through this, we will get through anything," he said. In Taihape farmers' reserve feed is getting diminished, because they had a "pretty tight" spring. "We used to be summer safe and we are not summer safe any more," Mr Hughes said.
"It's compounding on the top of the 2013 drought, which we had to manage even more intensively. If this follow-up rain doesn't come we will be back in the same position."
Manawatu-Wanganui is just one of many New Zealand regions where soil moisture is less than normal.
Professor David Frame, an internationally renowned climate researcher at Victoria University, said scientists were trying to understand the links between extreme weather events and climate change.
"The extreme events we've experienced recently are a cause for people to think about how they prepare for a changing climate."