Climate outlook for April to June
Issued 26 March 2015
Climate outlook overview
- April to June is likely to be wetter than normal over most of the Australian mainland, outside of the tropics. The tip of the Cape York Peninsula in Queensland is likely to be drier. Elsewhere, the chances of a wetter or drier season are roughly equal.
- For April, large parts of the mainland are likely to be wetter than normal, with northeastern parts having a roughly equal chance of a wetter or drier month.
- For April to June, warmer than normal days are likely over the tropical north, parts of southeastern Australia, and the far southwest of WA. Daytime temperatures across parts of western and central WA, extending into western SA are likely to be cooler than normal.
- Night-time temperatures for the season are highly likely to be warmer than normal over most of Australia.
- The major climate influence for the season ahead is the warmer than normal sea surface temperatures in the Indian Ocean and that surrounding much of the Australian coastline. In the tropical Pacific, further warming is expected, with the Bureau's climate outlook model suggesting El Niño is likely during the latter part of the outlook period.
Wetter season likely for much of Australia
- April to June is likely to be wetter than normal over most of the Australian mainland, except in the tropical north and Tasmania where the chances of a wetter or drier season are roughly equal. The tip of the Cape York Peninsula in Queensland is likely to be drier than normal.
- Likewise, April is more likely to be wetter than normal over large parts of Australia. Chances of a wetter or drier April are roughly equal over Tasmania, and the northeastern half of Australia (see map).
- The major climate influence for the rainfall outlook is the warmer than normal sea surface temperatures in the Indian Ocean and that surrounding much of the Australian coastline. In the tropical Pacific, further warming is expected, with the Bureau's climate outlook model suggesting El Niño is likely during the latter part of the outlook period.
- Historical outlook accuracy for April to June is moderate over most of Australia but low in Tasmania and parts of southeast Australia (see map for detail).
High chance of warmer nights for most of Australia
- Daytime temperatures for April to June are likely to be warmer than normal over the tropical north, parts of southeastern Australia, and the far southwest of WA.
- Across parts of western and central WA, extending into western SA, days are likely to be cooler than normal. This is likely a result of the increased chance of a wetter season over the area.
- Overnight temperatures are likely to be warmer than normal for most of Australia. Chances are greater than 80% across most of Australia, except for parts of WA. With the rainfall outlook suggesting wetter weather, this means more cloud is likely to be present, which aids in trapping heat at night.
- The main climate influences are the warmer than normal sea surface temperatures in the Indian Ocean and that surrounding much of the Australian coastline. In the tropical Pacific, further warming is expected, with the Bureau's climate outlook model suggesting El Niño is likely during the latter part of the outlook period.
- Historical maximum temperature accuracy is moderate to high over Australia. Minimum temperature accuracy is also moderate to high over Australia, except southwestern WA, where accuracy is moderate to low.
Climate influences
- Sea surface temperatures (SSTs) surrounding Australia continue to be warmer than normal. These warmer-than-normal SSTs extend into the eastern half of the Indian Ocean. This is likely to be influencing minimum temperature outlooks and the rainfall outlook, with both outlooks indicating a high chance of the season being warmer and wetter, respectively. With more rainfall forecast, more cloud is present, which aids in trapping heat at night.
- The tropical Pacific Ocean is currently neutral with respect to the El Niño–Southern Oscillation. However, SSTs remain warmer than average, and are expected to increase over the next three months. POAMA suggests El Niño conditions are likely to develop in late autumn to early winter. For eastern Australia, the development of more El Niño-like conditions, and thus a bias towards drier weather, may be opposing the influence from the Indian Ocean.
- While there is an increased chance of wetter conditions across much of the country, it is important to remember that this is relative to the 1981 to 2010 30-year period. This period is relatively dry (and the warmest) in the full historical record. For example, compared to the average for the full period of record (1900-2014) in southeast Australia, there have only been five above average April-June seasons in the last 20 years.
- Bureau climatologists continually monitor the climate for any significant developments, with information on the likelihood of El Niño/La Niña and IOD events available fortnightly via the ENSO Wrap-Up. For a summary of Pacific and Indian Ocean outlooks, please see the Climate Model Summary.
