The shift in rainfall away from the western Pacific, associated with El Nino, means that Australian rainfall is usually reduced through winter-spring, particularly across the eastern and northern parts of the continent.

Nine of the ten driest winter-spring periods on record for eastern Australia occurred during El Nino years. In the Murray-Darling Basin, winter-spring rainfall averaged over all El Nino events since 1900 was 28% lower than the long-term average, with the severe droughts of 1982, 1994, 2002 and 2006 all associated with El Nino

Australian winter spring mean rainfall deciles averaged for twelve strong El Nino events.

Although most major Australian droughts have been associated with El Nino, analysis of past El Nino events shows that widespread drought does not occur with every event, and the strength of an El Nino is not directly proportional to the rainfall impacts. For example, during the very strong El Nino that occurred in 1997–98 impacts on rainfall were generally confined to coastal southeastern Australia and Tasmania, while the relatively weak event of 2002–03 saw widespread and significant drough    

Growing season (April-November) rainfall anomalies for eastern Australian plotted against the SOI averaged for April–November for all years from 1900 to 2013, showing the varied effect of both strong and weak El Nino events on rainfall. El Ninois typically associated with sustained negative SOI values.

El Niño years tend to see warmer-than-average temperatures across most of southern Australia, particularly during the second half of the year. In general, decreased cloud cover results in warmer-than-average daytime temperatures, particularly in the spring and summer months. Higher temperatures exacerbate the effect of lower rainfall by increasing evaporative demand. Prior to 2013 (a neutral ENSO year), Australia’s two warmest years for seasonal daytime temperatures for winter (2009 and 2002), spring (2006 and 2002), and summer (1982–83 and 1997–98) had all occurred during an El Niño. The warmth of recent El Niño events has been amplified by background warming trends which means that El Niño years have been tending to get warmer since the 1950s.

Australian winter–spring mean maximum temperature deciles averaged for twelve strong El Niño events.

For temperature extremes, there are three different measures of heat that are relevant to El Niño: wide-area heatwaves (as indicated by a very warm national area-average temperature); single-day extremes at specific point locations; and long-duration warm spells. The relationship of El Niño with each of these elements may be quite different, and location dependant.

During the warmer half of the year, there is a tendency for weather systems to be more mobile during El Niño years, with fewer blocking (stationary) high pressure systems. This means that for southern coastal locations such as Adelaide and Melbourne, individual daily heat extremes tend to be of greater intensity (hotter) during El Niño years but there is a reduced frequency of prolonged warm spells. Further north, El Niño is associated with both an increase in individual extreme hot days and multi-day warm spells.

Although maximum temperatures are generally warmer than average during El Niño years, decreased cloud cover often leads to cooler-than-average night-time temperatures during winter–spring, particularly across eastern Australia. For example, regions of southern New South Wales and northern Victoria can experience 15–30% more frost days during El Niño than the historical average; frost days which occur during spring can have significant impacts on agriculture. The Australian record cold temperature of −23.0 °C was observed at Charlotte Pass, New South Wales, on 29 June 1994 in an El Niño year.

On average, there are fewer tropical cyclones in the Australian region during El Niño years. This is particularly true around Queensland, where cyclones are half as likely to cross the coast during El Niño years compared to neutral years. This means a decreased likelihood of major damage and flooding related to strong winds, high seas and heavy rains associated with tropical cyclones.

The date of the monsoon onset in tropical Australia is generally 2–6 weeks later during El Nino years than in La Nina years. This means that rainfall in the northern tropics is typically well-below-average during the early part of the wet season for El Nino years, but close to average during the latter part of the wet season.

Australian mean rainfall deciles during October–December (left) and February–April (right) averaged for twelve strong El Niño events.

As a result of decreased rainfall and increased maximum temperatures, the frequency of high fire danger ratings and risk of a significant fire danger season in southeast Australia are significantly higher following an El Niño year, particularly when combined with a positive Indian Ocean Dipole (IOD) event. Some El Niño years have been followed by very severe summer fires, including Ash Wednesday (16 February 1983) and the 2002–03 and 2006–07 seasons.

However, not all major fires follow El Niño years. The spring bushfires in the Blue Mountains during October 2013 occurred during a neutral ENSO year, while Black Saturday (7 February 2009) in fact followed a weak La Niña (but notably, a positive IOD).

El Nino years (as well as positive IOD years) tend to have lower snow depths in Australia’s alpine regions. On average, the peak snow depth measured at Spencer’s Creek is 35 cm lower during El Nino years, and the season length (i.e. the period of time with snow depths greater than 100 cm) is 2.5 weeks shorter. The four lowest peak snow depths on record were all measured during El Nino years; notably, snow depths never reached 100 cm in 1982 or 2006.

However, El Nino does not guarantee a poor snow season. Indeed, three El Nino years (1972, 1977 and 1991) actually had well-above-average peak snow depths. Cooler night-time temperatures and lower rainfall during El Nino years can often mean that the snow which does fall is retained and can aid artificial snowmaking which many resorts use to supplement the natural snow they receive.