How accurate are weather forecasts?
Weather forecasts are generally accurate, particularly over the next few days. They become less certain the further into the future they extend. Forecasts for the next 2 to 3 days are generally more accurate than toward the end of the 7-day period.
It also depends where you are in Australia, and at what time of year. For example, in Darwin during the dry season, the weather is more stable. You can have a higher level of confidence in the 7-day forecast compared to the same period in Melbourne, where a change in the timing of cold fronts can dramatically alter the forecast.
Forecasts describe what is most likely to happen but there are always a range of possibilities. Forecasts indicate the likelihood of rain, severe weather or seasonal conditions. They can help you make informed decisions, even when exact outcomes cannot be known.
Measuring forecast accuracy
To know whether forecasts are accurate we compare them with real world observations. For example, how much rain fell or how warm it was.
This comparison happens:
- using the same method
- over long periods
- using lots of quality-controlled data points.
This process is called verification.
Verification
Verification compares forecasts with observations, such as:
- recorded temperatures
- rainfall totals
- wind speeds.
Verification helps the bureau:
- monitor forecast quality and performance across different locations and timeframes
- improve forecast and warning services
- compare, evaluate and improve forecast models.
It also enables our annual reporting on forecast accuracy.
Understanding weather model limits
We use sophisticated computer models to forecast the weather. While the models are very good, it is still impossible to exactly simulate the evolution of weather around the Earth.
Differences between the model and real world may be very small at the start of a forecast period. But as we ask the model to forecast further into the future, these differences become larger. This is why longer-range forecasts are less certain.
Learn more about weather models.
Short-range forecast accuracy
Short-range forecasts cover the next hours up to 7 days. They generally give the greatest level of local detail and are the most accurate.
Temperature and wind often change gradually across large areas, making them relatively easier to predict.
Rain can vary significantly over short distances, particularly during showers and thunderstorms. This makes it harder to forecast. Learn about rain forecasting.
For hourly, daily and weekly forecasts:
- search for your location on any page of this website, or in Forecasts and observations
- download the BOM Weather app. Select up to 3 locations for warning and rain notifications.
Long-range forecast accuracy
Our long-range forecasts help show what the season ahead is likely to bring. They cannot predict individual high-impact weather events. These events, such as tropical cyclones, can influence how the season turns out.
The bureau uses an Australian model for long-range forecasting. Our climatologists also consider information from international forecasting centres. Learn how we produce long-range forecasts.
We update long-range forecasts regularly. Find out why forecasts change.
Reporting on forecast accuracy
Each year we report the timeliness and accuracy of the bureau's forecasts. These reports are usually at a national scale, covering:
- temperature
- rainfall
- wind
- waves
- floods.