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When are there jellyfish in Australia?

Australian box jellyfish are recorded most in February and March — and this is the one that matters, because the sting can kill.

Australian box jellyfish (can be fatal)

Recorded well above the expected rate in February and March, peaking at 4.5× the expected rate. Based on 149 records.

MonthJanFebMarAprMayJunJulAugSepOctNovDec
Recorded vs expected 0.5 4.5 2.6 0.6 0.3 0.3 0.0 0.0 0.3 0.8 1.0 0.7

Box jellyfish (severe sting)

Recorded well above the expected rate in January and December, peaking at 2.7× the expected rate. Based on 1,711 records.

MonthJanFebMarAprMayJunJulAugSepOctNovDec
Recorded vs expected 2.7 1.1 1.1 1.2 0.6 0.3 0.2 0.1 0.2 0.3 1.0 2.6

Portuguese man o' war (severe sting)

Recorded well above the expected rate in April, peaking at 1.3× the expected rate. Based on 1,844 records.

MonthJanFebMarAprMayJunJulAugSepOctNovDec
Recorded vs expected 1.2 0.9 1.1 1.3 1.0 0.4 1.1 0.9 0.8 1.2 0.9 1.2

Mauve stinger (painful sting)

Above the expected rate in May, June and October — but those months sit in different parts of the year rather than forming one season, so the monthly figures below are worth more than any summary of them would be. Based on 228 records.

MonthJanFebMarAprMayJunJulAugSepOctNovDec
Recorded vs expected 0.5 0.7 0.7 1.1 2.1 1.8 0.8 0.8 0.9 1.7 0.7 0.3

True jellyfish (varies by species)

Recorded well above the expected rate in January and February, peaking at 1.4× the expected rate. Based on 6,945 records.

MonthJanFebMarAprMayJunJulAugSepOctNovDec
Recorded vs expected 1.4 1.4 1.1 0.8 1.2 0.6 0.7 0.6 1.0 1.1 0.8 1.1

Sea temperature in Australia

Records from GBIF, the Global Biodiversity Information Facility. How the adjustment works