The El Niño in the Pacific is now one of the three strongest ever recorded.

The Bureau of Meteorology said sea surface temperatures in the central and eastern tropical Pacific, a key driver of the climatic phenomenon, were 2.4C above average – the highest since the El Niño was declared six months ago.

El Niño usually brings below-average rain and increased daytime temperatures, particularly to eastern Australia in the southern spring. The bureau’s latest El Niño southern oscillation wrap-up said the strength compares with the two strongest recorded – in 1997-98 and 1982-83.

Both brought devastating droughts to eastern Australia.

“International climate models suggest the peak in El Niño sea surface temperatures is likely to occur before the end of the year, then gradually ease in the first quarter of 2016,” the wrap-up said.

Typically, El Niño’s influence on rainfall decreases, although warmer daytime and night-time temperatures tend to persist.

But record warm sea-surface temperatures in the Indian Ocean may cause below-average rainfall to drag on across Australia, the bureau warned.

This warming, known as the Indian Ocean Dipole (IOD), has existed for more than three months, with temperatures now 0.88C above average – the highest anomaly since reliable records began in 1981.

The record has already been broken twice this spring – in September (+0.52C) and October (+0.65C).

An above-average IOD tends to reinforce the effect of an El Niño, especially in the south-east. It is expected the dipole will begin to degrade later in November.

Despite recent rainfall in some areas, parts of inland Queensland, northern and western Victoria and southern South Australia have severe or record rainfall deficiencies stretching back as much as three years.