A brief summary of climate and hydrological conditions in the region.
This service is only 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.
Updated 24 February 2022. Next update due when there is a significant change of conditions, as the situation evolves.
Very significant, widespread rain fell in the region in February. The strongest system was a heavy moisture flux (atmospheric river event) from the tropics, associated with ex-Tropical cyclone Dovi. Rainfall above four times the average fell in some areas, with the Wairarapa more affected than the western side of the region.
While there was significant flood and some negative impacts for agricultural sectors such as the grape quality during the harvest, in general the abundant rainfall and soil moisture replenishment were welcomed by Wairarapa farmers. The eastern hills have specially benefited from it.
La Niña remains influencing our weather systems, with significantly warmer than average Sea Surface Temperatures (SST) around New Zealand, and a mostly positive Southern Annular Mode (SAM).
These combined conditions tend to amplify the classic La Niña signature of above average temperatures with greater humidity, dry spells and thunderstorms.
Most dynamical climate models are predicting the persistence of high pressure east of New Zealand into autumn, continuing with significantly warmer than average seasonal temperatures.
A prevailing La Niña north-easterly flow is expected to alternate with strong westerlies. Very humid conditions under the influence of moist tropical air masses are expected to continue to occur while the SSTs around New Zealand remain warm.
Rainfall distribution should continue to be irregular, with extended dry periods followed by further bursts of extreme rainfall events.
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 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 a “new normal” climate pattern, significantly drier than in the past.
We note that the warming temperatures also mean that evapotranspiration will greatly increase. There is some evidence that our soils are getting drier, and groundwater storage may be decreasing, in the long-term.
Browse the data
How different has recent rainfall/soil moisture been compared with the same time in previous years?
|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|
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