Coming season to become progressively more active for NZ
July-September climate outlook highlights include:
• A weak, central Pacific El Niño continued during June as sea surface temperatures (SSTs) remained more than 0.7C above average (i.e. the El Niño threshold) for the fourth consecutive month.
• While El Niño is expected to continue over the coming three-month period (60% chance), it may gradually weaken and become less influential on the global climate system.
• For the July to September period, air pressure is forecast to be higher than normal to the northwest of New Zealand and lower than normal to the south. This is expected to be associated with more westerly quarter winds to start the season and mixed flow patterns later. There may be a trend toward more unsettled weather during the coming season, particularly in September.
• Temperatures are forecast to be near average or above average for all regions of New Zealand, owing to warmer than average coastal and regional sea surface temperatures.
• Warm spells are possible on occasions during July and particularly August when air flows extend from Australia from time to time.
• Rainfall is forecast to be near normal or below normal in the north of the North Island and north and east of the South Island. Near normal rainfall is forecast in all other regions of New Zealand.
• As the season progresses, high pressure systems may become less frequent in the New Zealand region, contributing to more regular rainfall events.
• Despite a low chance for below average seasonal temperatures, cold snaps and frosts remain likely to occur.
The full seasonal climate outlook and graphics showing rainfall and temperature projections are attached.