Current climate: April 2018

Overall, April 2018 was characterised by lower pressure than normal over and to the southeast of New Zealand. Unlike the first three months of the year where La Niña conditions promoted more winds from a northeasterly direction, April’s pressure pattern resulted in more southwesterly winds than normal for much of the country. Several low pressure systems and cold fronts passed over New Zealand during April, bringing adverse weather to many locations.

Temperature

Mean temperatures were above average (0.51 to 1.20°C of average) or well above average Near average temperatures (-0.50 to +0.50°C of average) in the southeast of the North Island as well as parts of the central North Island (north Taranaki through to Napier) and East Cape. Above average (+0.51 to +1.20°C of average) temperatures elsewhere in the North Island. In contrast, large parts of central Canterbury, Fiordland, and the West Coast experienced below average (-0.50°C to -1.20°C of average) temperatures while the rest of the South Island observed mostly near average temperatures.

Rainfall

Above normal (120% to 149% of normal) or well above normal (>149% of normal) rainfall over Auckland City, Coromandel Peninsula, most of the Wellington region, a large portion of the central North Island, and most of the South Island, particularly in the east. Near normal rainfall (80% to 119% of normal) in patches of the South Island, including Tasman, Marlborough, central West Coast, and parts of Southland. Near normal rainfall also occurred over western Northland and the western part of the central North Island. Below normal (50% to 79% of normal) or well below normal (<50% of normal) rainfall for East Cape, eastern Northland, and localised patches in the Taranaki and Manawatu-Whanganui regions.

Soil Moisture

By the end of April, soil moisture levels were above normal for much of the South Island except along the West Coast and in Southland where levels were near normal. In the North Island, soils were drier than normal for East Cape, as well as parts of Manawatu-Whanganui, and southern parts of Northland. Remaining locations in the North Island were wetter than normal. 

Departure from average air temperature for April 2018.
End of month water balance in the pasture root zone for an average soil type where the available water capacity is taken to be 150 mm.
Percentage of normal rainfall for April 2018.