7:20am 05/08/2026 to 7:20am 07/08/2026
Maximum observed rainfall by duration, estimated return period and AEP
Duration
Rainfall
Start
End
Years
AEP
10m
1.0 mm
3:40pm 06/08/2026
3:50pm 06/08/2026
1 in 1 years
100.0 %
20m
2.0 mm
3:40pm 06/08/2026
4:00pm 06/08/2026
1 in 1 years
100.0 %
30m
2.0 mm
3:30pm 06/08/2026
4:00pm 06/08/2026
1 in 1 years
100.0 %
60m
2.0 mm
3:00pm 06/08/2026
4:00pm 06/08/2026
1 in 1 years
100.0 %
90m
2.0 mm
2:30pm 06/08/2026
4:00pm 06/08/2026
1 in 1 years
100.0 %
120m
2.0 mm
2:00pm 06/08/2026
4:00pm 06/08/2026
1 in 1 years
100.0 %
3h
2.4 mm
1:00pm 06/08/2026
4:00pm 06/08/2026
1 in 1 years
100.0 %
4h
2.6 mm
3:40pm 06/08/2026
8:10pm 06/08/2026
1 in 1 years
100.0 %
6h
3.0 mm
3:40pm 06/08/2026
9:40pm 06/08/2026
1 in 1 years
100.0 %
9h
3.4 mm
1:00pm 06/08/2026
10:00pm 06/08/2026
1 in 1 years
100.0 %
12h
4.0 mm
3:40pm 06/08/2026
3:40am 07/08/2026
1 in 1 years
100.0 %
18h
5.2 mm
1:00pm 06/08/2026
7:00am 07/08/2026
1 in 1 years
100.0 %
24h
5.4 mm
7:20am 06/08/2026
7:20am 07/08/2026
1 in 1 years
100.0 %
30h
5.6 mm
1:20am 06/08/2026
7:20am 07/08/2026
1 in 1 years
100.0 %
36h
5.6 mm
7:20pm 05/08/2026
7:20am 07/08/2026
1 in 1 years
100.0 %
48h
5.6 mm
7:20am 05/08/2026
7:20am 07/08/2026
1 in 1 years
100.0 %
Note: A '1 in 1.0 years' estimate means that it is almost certain to occur at least once in a year, and could occur much more than once per year on average. For smaller values like this the Annual Recurrance Interval (ARI) may be of more relevance, but it is complex to calculate for common events.
IFD describes how rainfall intensity relates to how long it lasts and how often it happens. It is the basis for design rainfall used in engineering and flood studies.
- Duration: the length of the rainfall burst, from a few minutes to several days.
- AEP (Annual Exceedance Probability): the chance, in any one year, of a rainfall of that depth or greater. A 1% AEP event has a 1 in 100 chance each year - what is often loosely called a '1 in 100 year' event.
- The curves show design rainfall depths for a range of AEPs. The observed maximums for this location and period are plotted against them so you can see how rare the event was.
Design rainfall data is sourced from the Bureau of Meteorology.

