Seasonal Climate Outlook

New Zealand’s regional climate over the next three month period is anticipated to be dominated by the very warm ocean waters present around the country and in the Tasman sea, which will influence surface air temperatures and the likelihood of significant rainfall events.

La Niña conditions are present in the tropical Pacific, as several conventional thresholds have been reached or are being approached.

The tropical Pacific is still officially in a ENSO (El Niño Southern Oscillation) neutral state, but some indicators have leaned more towards La Niña conditions during the course of October 2017.

Many atmospheric and oceanic indicators in the tropical Pacific are on the La Niña side of neutral, although not yet strong enough to reach La Niña thresholds.

ENSO (El Niño – Southern Oscillation) neutral conditions were still present in the tropical Pacific during August 2017. However, like July, several oceanic and atmospheric patterns, such as the Southern Oscillation Index (SOI) and decreasing sea surface temperatures (SSTs) in the tropical Pacific, leaned toward La Niña.

ENSO (El Niño – Southern Oscillation) neutral conditions (neither El Niño nor La Niña) continued in the tropical Pacific during July 2017, but this month mixed signals were again present. In particular some atmospheric patterns have been recently leaning more towards weak La Niña conditions.

The tropical Pacific remained in an ENSO (El Niño – Southern Oscillation) neutral state (neither El Niño nor La Niña) during June 2017, but oceanic and atmospheric anomalies were mixed, with some indicators leaning towards El Niño and others towards La Niña.

The tropical Pacific continued to exhibit an ENSO (El Niño – Southern Oscillation) neutral state (neither El Niño nor La Niña) during May 2017, although is now close to the threshold of a weak El Niño. 

The tropical Pacific overall remained in an ENSO (El Niño – Southern Oscillation) neutral state  (neither El Niño nor La Niña) during April 2017. The strong ‘coastal El Niño’ which developed along the coast of South America (southern Ecuador and northern Peru) during February and March has now weakened.

The tropical Pacific is currently in an ENSO (El Niño – Southern Oscillation) neutral state overall, but with very mixed signals.

The tropical Pacific is currently in an ENSO (El Niño – Southern Oscillation) neutral state (neither El Niño nor La Niña).

The tropical Pacific is currently in an ENSO (El Niño – Southern Oscillation) neutral state (neither El Niño nor La Niña).

The tropical Pacific continues to exhibit mainly ENSO-neutral conditions.

The tropical Pacific exhibits mainly neutral ENSO (El Niño-Southern Oscillation) conditions. Sea surface temperatures (SSTs) in the central Equatorial Pacific Ocean are marginally below average and do not exceed the threshold used by NOAA’s Climate Prediction Center to define La Niña events.

The tropical Pacific exhibits mixed ENSO (El Niño-Southern Oscillation) signals, with some indicating La Niña status and others indicating neutral conditions.

ENSO (El Niño – Southern Oscillation) neutral conditions are still present in the tropical Pacific Ocean as a whole, although some indicators are currently in the weak La Niña category.

ENSO (El Niño – Southern Oscillation) neutral conditions continued in the tropical Pacific Ocean during August: sea surface temperatures along the eastern equatorial Pacific are near or slightly below normal, and the atmospheric conditions over the tropical Pacific are generally consistent with an ENSO-neutral state.

ENSO (El Niño – Southern Oscillation) neutral conditions are currently present in the tropical Pacific.

The latest remnants of the strong El Niño which peaked late in 2015 have now vanished in the tropical Pacific Ocean, and the Pacific is ENSO-neutral.

Ocean-atmosphere conditions in the tropical Pacific have now returned to near normal after a rapid demise of the El Niño event that peaked late 2015.

El Niño conditions in the tropical Pacific weakened further during April 2016, with sea surface temperatures now typically only about +1oC warmer than normal.