Southland farmers hoping for a dry run into summer will have to wait, with Earth Sciences New Zealand forecasting another 50 to 100 millimetres of rain across most of the region next week.

The agency's weekly Hotspot Watch, released on Wednesday, says a moist northerly flow will develop from Sunday, bringing heavy rain to the west of the South Island that peaks overnight into Monday 2 November and continues through the week.

Most of Southland, along with Otago and Canterbury close to the Main Divide, is expected to receive 50 to 100mm. Coastal Otago is likely to get 20mm or less, and the rest of the South Island 25 to 50mm.

Before that, fronts will cross the region on Thursday and Friday, with a settled day expected on Saturday.

Southland's soils are already carrying more moisture than usual for late October. Western Southland received 50 to 100mm in the past week, and the rest of the region and Queenstown-Lakes 20 to 50mm, lifting soil moisture across the South Island. Inland Otago has the wettest soils in the country for the time of year.

There are no dryness hotspots anywhere in the South Island, and none are expected to form. The contrast with the north is stark: a small hotspot has developed around East Cape, and parts of Northland, Bay of Plenty and Gisborne are abnormally dry.

A season of mud

The forecast lands on farms still dealing with the aftermath of the wettest winter since 1980 and a third wet spring in a row.

The Government classified conditions in Southland and Clutha as a medium-scale adverse event on 1 October, unlocking $50,000 for the Southland and Otago Rural Support Trusts, more flexible tax arrangements and the possibility of Rural Assistance Payments for families who cannot meet living costs.

Federated Farmers Southland president Chris Dillon said at the time: "For many farmers, feed for their livestock is very tight – or gone." Farmers Weekly reported in September that soils were saturated, pasture covers were tight and only four days in three weeks had been rain-free.

RNZ's rural news on Wednesday morning reported some respite for Southland farmers and growers after one of the wettest seasons in almost half a century, and warmer conditions in recent weeks have helped southern growers.

El Niño's southern twist

Longer-range guidance offers little certainty. Earth Sciences New Zealand's outlook through late November ranges from a drier scenario that leaves the north and east of the South Island short of rain, to a wetter scenario with much wetter conditions across the western and southern South Island.

An Environment Southland report in July found annual rainfall in the region was 10 to 14 per cent higher in El Niño years than in La Niña or neutral years, with the biggest increase in summer. The council's general manager science, Karen Wilson, said then that the south was in a different position from most of the country, which was preparing for drought.

With the current El Niño now rated very strong, the question for Southland is less whether summer will be dry than whether its paddocks will get a chance to dry out at all.