Monitoring drought
Rainfall reporting and analysis
We closely monitor and report on the amount of rain Australia receives, including when areas are receiving less rain than usual.
To do this, we compare current rainfall to historical data for the same area, at the same time of year. We use gridded national analysis of rainfall records going back to 1900.
For meteorological drought, we have historically analysed rainfall totals over at least a 3-month period. This provides a clearer indication of rainfall trends. However, drought conditions can develop over periods of less than 3 months.
All the rainfall totals since 1900 for these periods are ranked in order from driest to wettest. Rainfall totals in the lowest 10% are considered to be in 'deficiency'.
Describing rainfall deficiencies
We use these terms to describe the amount of rainfall, measured against data collected since 1900:
Lowest on record – lowest rainfall total
Highest rainfall total – highest rainfall total
Severe deficiency – rainfalls in the lowest 5%
Serious deficiency – rainfalls in the lowest 5–10%
Very much below average – rainfalls in the lowest 10%
Below average – rainfalls in the lowest 10–30%
Average – rainfalls in the middle 40%
Above average – rainfalls in the highest 10–30%
Very much above average – rainfalls in the highest 10%
Understanding water resources
If below-average rainfall continues over months or years, water storages are depleted. Dam and reservoir levels drop. The soil dries, river levels drop (some may dry up completely), and groundwater levels fall.
To understand the bigger drought picture, we provide information about water resources. We do this by:
- modelling soil moisture
- modelling the nature and intensity of drought
- measuring and forecasting streamflow
- analysing groundwater data.
We provide the Australian Water Outlook. It has current, historical and forecast information about Australia's water resources.
Forecasts – rainfall, streamflow and water resources
Long-range forecasts
Our long-range forecasts show whether rainfall is likely to be above or below average for the coming months and season ahead.
You'll find the latest long-range forecast on our current website – we're still building this new one.
Australian Water Outlook
The Australian Water Outlook has forecasts for Australia's water resources, including:
- soil moisture
- runoff
- evapotranspiration.
If it's already dry and soil moisture is low, the actions you take based on this information may be different from when there's plenty of water around.
Seasonal Streamflow Forecast
The Seasonal Streamflow Forecast shows likely streamflow volumes for the coming 1, 2 and 3-month periods. It covers more than 250 locations across Australia. This information can inform decision making and scenario planning for river use and water storages.
Drought Statements
Our monthly Drought Statement reports on the extent and severity of dry conditions.
It outlines recent rainfall compared to historical records and the impacts on soil moisture and water resources.
These statements include maps showing areas of rainfall deficiency, soil moisture conditions and water storage levels.
Rainfall maps and updates
Rainfall maps
Our rainfall maps allow you to see which areas are in the lowest 10% of historical rainfall observations – select 'drought' in the first drop-down menu. Visit the rainfall maps on our current website.
Rainfall update
The rainfall update outlines rainfall describes recent rainfall across Australia. It includes:
- recent weather station rainfall totals for selected periods of up to 3 years
- weekly rainfall highlights.
See the latest rainfall update on our current website.
Special Climate Statements
Our Special Climate Statements document major weather and climate events. We publish them when an event is unusual for a region.
Special Climate Statements:
- provide information about the event
- are a historical record
- give the history and climate context for events.
You'll find the Special Climate Statements on our current website.