New Zealand climate in May 2005
Record rains lashed Bay of Plenty, with severe flooding. Tauranga recorded 634 mm (695 percent of normal), its wettest calendar month for any time of the year in more than a century, including its heaviest 1-day rainfall on record (347 mm on 18 May).
May was very much warmer than usual in the North Island, but temperatures were below average along the South Canterbury and Otago coasts. The national average temperature for May was 11.4 °C, which was 0.7 °C above the historical average.
For more information on the climate in May, visit the climate summaries page at www.niwa.co.nz/ncc/cs/mclimsum_05_05
Global setting and climate outlook
Warming short lived
While surface waters along the equator in the eastern Pacific warmed rapidly in late April and early May, hinting at a possible return to El Niño, these developments appear to have been a short-lived perturbation.
The Southern Oscillation Index (SOI) dropped slightly in May to –1.5, giving a three-month mean of –1.0. Despite the continuing negative SOI, the tropical Pacific is presently in a neutral state (no El Niño or La Niña). Conditions are likely to stay in the neutral range through winter and into early spring