Bogong Moths Make Australian Weather Radars Look Like Rain
By Chloe · Published 20 Oct 2026 · Updated 20 Oct 2026
Sydney, NSW · New South Wales News
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Smart summary
Large numbers of migrating bogong moths are creating radar signals that resemble rainfall, even on clear nights.
Weather radars across south-eastern Australia have been detecting signals that look like widespread rain, but the unusual activity has another explanation: millions of migrating bogong moths. According to ABC News, the Bureau of Meteorology (BOM) has observed radar echoes across eastern New South Wales, with similar activity also appearing in parts of Victoria.
The phenomenon has attracted attention because the radar images can show apparent rainfall even when the sky is clear and no rain is falling. The equipment is not necessarily malfunctioning. Instead, the radar signals are being reflected by objects in the atmosphere other than raindrops.
Weather radar works by sending out pulses of radio waves and measuring the signals that bounce back. These returns help meteorologists estimate where precipitation is occurring and how it is moving. However, insects, birds, aircraft, smoke and certain atmospheric conditions can also produce radar echoes. When enormous numbers of moths fly together, their combined signals can resemble light, widespread rainfall.
The timing of the signals provides an important clue. The unusual echoes tend to appear after sunset, when the moths become active after spending daylight hours resting in sheltered places. The distribution of the radar signals also appears to correspond with reported moth sightings across parts of eastern Australia.
Bogong moths undertake a remarkable seasonal migration towards the Australian Alps, where they spend the warmer months in cooler alpine environments. Their migration is an important natural event, and the insects provide food for other wildlife. The species has experienced serious population declines in recent decades and was listed as endangered in 2021. The recent increase in sightings has therefore attracted interest from researchers and conservationists.
The radar interference can create confusion for some weather applications. Apps that rely on unverified radar signals may interpret the echoes as approaching rain and issue precipitation alerts. However, the BOM says standard weather forecasts are not affected in the same way because they also rely on weather models, ground observations and satellite information. People should therefore check official forecasts rather than assuming every radar signal represents actual rainfall.
There is also a historical precedent. During the 2000 Sydney Olympics, moths attracted to stadium lights produced radar signals that initially suggested rain might be approaching during the closing ceremony. The episode illustrates how wildlife can occasionally create unexpected challenges for meteorologists.
Scientists are continuing to learn more about the moths’ movements and how radar technology can help track them. The current activity offers an unusual example of how equipment designed to monitor weather can also reveal information about wildlife.
For residents in affected areas, the main message is simple: a patch of apparent rain on a radar map does not always mean precipitation is falling. Checking the official forecast and observing local conditions can help distinguish genuine weather from signals caused by migrating insects.
RadarSignalsWeatherMothsAlso
Weather radars across south-eastern Australia have been detecting signals that look like widespread rain, but the unusual activity has another explanation: millions of migrating bogong moths. According to ABC News, the Bureau of Meteorology (BOM) has observed radar echoes across eastern New South Wales, with similar activity also appearing in parts of Victoria.
The phenomenon has attracted attention because the radar images can show apparent rainfall even when the sky is clear and no rain is falling. The equipment is not necessarily malfunctioning. Instead, the radar signals are being reflected by objects in the atmosphere other than raindrops.
Weather radar works by sending out pulses of radio waves and measuring the signals that bounce back. These returns help meteorologists estimate where precipitation is occurring and how it is moving. However, insects, birds, aircraft, smoke and certain atmospheric conditions can also produce radar echoes. When enormous numbers of moths fly together, their combined signals can resemble light, widespread rainfall.
The timing of the signals provides an important clue. The unusual echoes tend to appear after sunset, when the moths become active after spending daylight hours resting in sheltered places. The distribution of the radar signals also appears to correspond with reported moth sightings across parts of eastern Australia.
Bogong moths undertake a remarkable seasonal migration towards the Australian Alps, where they spend the warmer months in cooler alpine environments. Their migration is an important natural event, and the insects provide food for other wildlife. The species has experienced serious population declines in recent decades and was listed as endangered in 2021. The recent increase in sightings has therefore attracted interest from researchers and conservationists.
The radar interference can create confusion for some weather applications. Apps that rely on unverified radar signals may interpret the echoes as approaching rain and issue precipitation alerts. However, the BOM says standard weather forecasts are not affected in the same way because they also rely on weather models, ground observations and satellite information. People should therefore check official forecasts rather than assuming every radar signal represents actual rainfall.
There is also a historical precedent. During the 2000 Sydney Olympics, moths attracted to stadium lights produced radar signals that initially suggested rain might be approaching during the closing ceremony. The episode illustrates how wildlife can occasionally create unexpected challenges for meteorologists.
Scientists are continuing to learn more about the moths’ movements and how radar technology can help track them. The current activity offers an unusual example of how equipment designed to monitor weather can also reveal information about wildlife.
For residents in affected areas, the main message is simple: a patch of apparent rain on a radar map does not always mean precipitation is falling. Checking the official forecast and observing local conditions can help distinguish genuine weather from signals caused by migrating insects.
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