A brief summary of climate and hydrological conditions in the region.

This service is regularly updated during periods in which closer monitoring is required (regardless of time of the year), in recognition that there is potential for dry spells, or irregular hydrological recharging. It does not define an official council position on drought or drought declaration. Outside of dry periods, less frequent updates synchronise with our latest seasonal outlooks.

Updated 19 March 2025

Next update due when there is a significant change of conditions or a new seasonal outlook.

Background

The new year brought well above average rainfall for the Wairarapa. While February was extremely dry for the entire region, for the total seasonal accumulation we had a positive water balance east of the main ranges. It was drier than normal towards the Kāpiti, Hutt Valley and Wellington as shown below. A weak La Niña presented little opportunity for ‘coupling’ between the ocean and the atmosphere. As a result, the main summer flow presented intermittent easterlies or south-easterlies diverging from a traditional La Niña. The oceanic water temperatures have been well above average over the Tasman Sea, but much cooler immediately east of New Zealand due to strong southerly bursts that have largely disrupted the normal summer flow.  

Colour coded map showing amount of rainfall in the region over summer 2024/25, with higher than average rainfall in the Wairarapa
Summer rainfall anomalies show the Wairarapa with slightly above average rainfall, and below average west of the ranges. A La Niña signature in the atmospheric flow was present at times, but not nearly as warm and humid as a traditional La Niña. Credits: GWRC
View full image open_in_new

Current situation

Soil moisture levels have been below average west of the main ranges and back near normal for the most part in the Wairarapa, after an extremely dry February. The national drought index is showing most of the region classed as dry, especially west of the Tararua ranges where the lack of rain has been much more persistent. A couple of fronts in March have brought some welcome relief, improving river flows and soil moisture.  While some smaller Ruamāhanga rivers and valley floor streams are back under water take restrictions after a couple of weeks of respite, most of the larger rivers have not yet receded back into restriction territory.

Meteorological outlook

International climate models are predicting that the atmosphere will continue to be influenced by an intermittent La Niña flow during autumn, before returning to a neutral ENSO state. This implies that we will likely continue to experience occasional fronts with some degree of ongoing recharging. Additional easterly rainfall events should prevent an aggravation of the normal seasonal dryness in the Wairarapa, going forward from the autumn equinox. Despite these favourable indicators from the main climate drivers, a continuing close monitoring is recommended.

Climate change

The ‘normal’ longer-term water balance is becoming increasingly hard to maintain quite possibly due to climate change influences, and increased high frequency climate variability, with more unreliable weather patterns. Droughts are expected to become more severe and frequent in the Wellington region, particularly in the Wairarapa. Even if international climate policy efforts were to successfully contain global warming under 1.5-2 degrees (the Paris Agreement’s ambition), it is important that we enhance our water resilience and be prepared for more unreliable climate patterns with both extreme dry and extreme wet periods. We note that the warming of the land also means that evapotranspiration will greatly increase, so the soil will likely need more ongoing rain to maintain ideal moisture levels, compared to what it has needed in the past.

View the latest national drought index state

View the national drought forecasting dashboard

View the latest seasonal report:

Browse the data

Anomaly Maps

How different has recent rainfall/soil moisture been compared with the same time in previous years?

30 Day Rainfall Anomaly

90 Day Rainfall Anomaly

1 Day Soil Moisture Anomaly

30 Day Soil Moisture Anomaly

 

Site-specific graphs

Cumulative rainfall/soil moisture totals for indicator sites compared with historical averages and other recent years. 
Area Rainfall Soil Moisture
Kapiti Coast (lowland) Otaki at Depot  
Kapiti Coast (high altitude) Penn Creek at McIntosh  
Porirua Horokiri Stream at Battle Hill  
Wellington City Kaiwharawhara Stream at Karori Reservoir  
Hutt Valley (upper catchment) Hutt River at Kaitoke Headworks  
Upper Hutt Upper Hutt at Savage Park Upper Hutt at Savage Park AQ
Wainuiomata Wanuiomata River at Wainui Reservoir  
Wairarapa (high altitude) Waingawa River at Angle Knob  
Wairarapa Valley (north) Kopuaranga River at Mauriceville  
Wairarapa Valley (Masterton) Ruamahanga River at Wairarapa College Wairarapa College AQ
Wairarapa Valley (south) Tauherenikau River at Racecourse Tauherenikau River at Racecourse
Wairarapa (north-eastern hills) Whareama River at Tanawa Hut Whareama River at Tanawa Hut
Wairarapa (south-eastern hills) Waikoukou at Longbush Waikoukou at Longbush
Updated March 18, 2025 at 4:25 PM

Get in touch

Phone:
0800496734
Email:
info@gw.govt.nz