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 3 December 2024
Next update due when there is a significant change of conditions or a new seasonal outlook.
Background
The El Niño/Southern Oscillation (ENSO) event responsible for the drought last summer is now swinging back to a likely weak La Niña. Winter and spring brought some beneficial hydrological recovery over the western catchments, but November was exceptionally dry in the Wairarapa. The combined dry and warm conditions have seen river and stream levels steadily fall. One or two valley floor streams have already reached a low flow state where restriction conditions for water users have been triggered, while other streams and smaller rivers (e.g. Mangatarere River) may not be far off if the dry spell continues.
Current situation
Soil moisture levels are now below average for most of the eastern hill country, and the national drought index is showing the eastern Wairarapa to be classed as dry. We note that southern Hawkes Bay is classed as already having drought conditions according to the national index, with a projection for the dry area to progressively envelop the Wairarapa towards the end of the year.
Meteorological outlook
International climate models are now predicting that the La Niña will only be a very weak event at best. However, as the climate change warming signal in the oceans tends to naturally amplify the moist subtropical influences around New Zealand through marine heatwaves, it is likely that the warm season will experience “La Niña-like” impacts at some point. The expectation is to transition from a more westerly, drier regime for the Wairarapa initially, moving towards a humid north-easterly flow. Various climate models are now suggesting that this transition will take place more likely towards late summer, implying the potential for a more significant dry period than originally anticipated into the new year.
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:
Climate drivers and seasonal outlook for the Wellington Region - Winter 2024 summary Spring 2024 outlook
date_range Published 20 Sep 2024
Download now (PDF 1.9 MB) get_appBrowse the data
Anomaly Maps
How different has recent rainfall/soil moisture been compared with the same time in previous years?
Site-specific graphs
| 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 |
Get in touch
- Phone:
- 0800496734
- Email:
- info@gw.govt.nz