About the Heatwave Service

Video Transcript

Frequently asked questions about this service

What is a heatwave?

Three or more days of high maximum and minimum temperatures that are unusual for that location.
Read more about heatwave and see some examples of the heatwave maps on our blog

When is the Heatwave Service available?

The Heatwave Service usually operates between October and March.

What is the Heatwave Service?

The Heatwave Service is a set of maps showing colour-coded heatwave severity for the previous two three-day periods, and the next five three-day periods.

What is heatwave intensity?

The bulk of heatwaves at each location are of low intensity, with most people expected to have adequate capacity to cope with this level of heat. Less frequent, higher intensity heatwaves are classified as severe and will be challenging for some more vulnerable people, such as those over 65, pregnant women, babies and young children, and those with a chronic illness. Even rarer and exceptionally intense heatwaves are classed as extreme and will impact normally reliable infrastructure, such as power and transport. Extreme heatwaves are a risk for anyone who does not take precautions to keep cool, even those who are healthy.

What does the Heatwave Assessment look like?

The Heatwave Assessment consists of a panel of two maps across Australia for the previous two three-day periods. Each map shows areas where heatwave conditions currently are and how they are contracting, and also indicate whether their intensity is severe or extreme status.

What does the Heatwave Forecast look like?

The Heatwave Forecast consists of a panel of five maps across Australia for the next five three-day periods. Each map shows areas where heatwave conditions are forecast to occur and also indicate whether their intensity is expected to reach severe or extreme status.

Why were these colours chosen?

The pale yellow colour was chosen for the lowest level of heatwave, allowing for the warmer colours of orange and red to show rising severity. These colours satisfy the Vision Australia recommendations for colour blindness.

How do we know a heatwave is coming?

Heatwaves are calculated using the forecast maximum and minimum temperatures over the next three days, comparing this to actual temperatures over the previous thirty days, and then comparing these same three days to the 'normal' temperatures expected for that particular location. Using this calculation takes into account people's ability to adapt to the heat. For example, the same high temperature will be felt differently by residents in Perth compared to those in Hobart, who are not used to the higher range of temperatures experienced in Perth.

This means that in any one location, temperatures that meet the criteria for a heatwave at the end of summer will generally be hotter, than the temperatures that meet the criteria for a heatwave at the beginning of summer.

How do we know a heatwave is finishing?

The heatwave assessment maps will help you understand how heatwave conditions are contracting. You are also encouraged to monitor official maximum and minimum temperature forecasts to see how cooler conditions are expected to relieve heatwave conditions.

What are the benefits of the Heatwave Service?

Heatwaves have a range of economic and planning impacts across a broad range of sectors, including health care, transport, emergency services, energy and agriculture. Impacts to these sectors may also have an effect on responding to people in need. Advance notice of a heatwave can help these sectors better prepare for these conditions, and reduce the level of impact to people,businesses and industry.

Australia is a hot country. Why do we need a heatwave service?

In the last 200 years, severe and extreme heatwaves have taken more lives than any other natural hazard in Australia. For example, during the 2009 Victorian bushfires, 173 people perished as a direct result of the fires; however 374 people lost their lives in the heatwave that occurred before the bushfires.

Why have heatwaves been described as a 'silent killer'?

Violent weather events, such as tornadoes, floods, cyclones or severe thunderstorms tend to create a lot of media attention, including reporting on how many people lost their life or were injured. Heatwaves are not associated with these violent events, and therefore tend to not be reported in the media to the same extent.

However, heatwaves can result in significant health stress on vulnerable people. This stress may result in death during the heat event but in many cases this can occur well after the heatwave has passed. Often the cause of death during a heatwave is difficult to determine, as many people who die during a heatwave have a pre-existing or contributing health condition.

Is climate change a contributing factor to heatwave events?

Climate projections show that extreme heat events are expected to occur more often and with greater intensity in the future.

When does a heatwave end?

Heatwaves finish when temperatures fall to more normal levels.


The maps provided by the Heatwave Forecast will show a reduced severity level or remove the indication of heatwave before the heatwave actually ends. This occurs because the maps are calculated across today, tomorrow and the next day. If the temperature is lower on the last day(s) then the map will indicate a lower risk despite unusually hot conditions being present for the first day or two. The Heatwave Assessment will show how heatwaves are finishing due to the combination of recent days with the current forecast days.

It is strongly recommended to monitor actual temperature forecasts for your location to understand when cooler conditions are expected to commence and therefore when the heatwave will finish.

Am I affected by the heatwave?

You may be affected if the map shows a heatwave is current in your area. If this is the case, it is prudent to prepare and modify your behaviour so you can cope more easily when extreme heat occurs. You may be more vulnerable to severe heat if you are over the age of 65, particularly if you have pre-existing medical conditions. It is best to consult your doctor if you are unsure.

I am on the edge of the heatwave area. Do I need to take precautions?

Predicting heatwaves is not exact due to the variations in forecast temperatures that can occur. If the heatwave map shows you are close to a heatwave region you may still experience the same conditions and should plan accordingly.

I am on the edge of the heatwave area. Where do I get more information on the areas affected?

You can go to the Bureau of Meteorology's website www.bom.gov.au/australia/. You should also listen to your local radio station for more information.

How much advance notification will I get?

The Heatwave Service provides information for the next seven days (five three-day periods).

Where can I get advice on how to protect myself from the effects of extreme heat?

Your own doctor or local health authorities understand extreme heat and can provide appropriate advice. Refer to the public health website in your state/territory for further information.

Does this mean we will have a bush fire?

Bush fires are triggered by a range of factors. Heatwaves affect the dryness of the fuels, which increases this hazard but it is only one factor. Listen to your local radio station and monitor your state's fire authority website for more information on bushfires.

I have lived through heatwaves before - why is this different?

Heatwaves are a normal part of summer conditions in Australia. Now there is a forecasting tool to predict when and where severe and extreme heatwaves are developing in order to help you take precautions and be better prepared.

Will electricity services be at risk in a heatwave?

Blackouts are more prevalent in severe and extreme heatwaves. Be prepared with an alternative source of power for radios and torches, and keep mobile phones fully charged where possible.

If we are having a heatwave does that mean the maximum temperature is going to be very high?

Heatwaves are more complex than just the daily maximum temperature. The minimum (or overnight) temperature is extremely important as well. If the minimum remains high then the subsequent maximum will occur earlier in the day and remain near that high temperature for a longer period. A higher minimum temperature also restricts the amount of recovery that can occur, due to less opportunity to discharge heat.

Why do we need a heatwave forecast?

Research has shown that heatwaves can increase health problems dramatically. By predicting when a heatwave will arrive it warns people, especially the vulnerable, to take precautions in advance. It also helps others like those who workoutside, those planning travel and those attending or participating in outdoor events.

I am a vulnerable person and don't have internet access. Is there any way I can get a personal notification of an impending heatwave?

At the moment there is no such service although this might be developed in future. In the meantime look in the newspapers, and listen to the radio or get a friend or relative with internet access to keep an eye on our website.

Future Developments

Following each summer period, the Heatwave Service maps will be evaluated for accuracy. The service is expected to be reviewed in conjunction with health and emergency sector stakeholders to consider the relevance of these assessment and forecast maps and how a comprehensive heatwave warning system should evolve.