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Light mode 7:30am 02/08/2026 to 7:30am 04/08/2026
You can find out more about Design Rainfall and IFD here.
Observations for this analysis :
Maximum observed rainfall by duration, estimated return period and AEP
Duration
Rainfall
Start
End
Years
AEP
10m
0.8 mm
6:30am 03/08/2026
6:40am 03/08/2026
1 in 1 years
100.0 %
20m
1.4 mm
6:30am 03/08/2026
6:50am 03/08/2026
1 in 1 years
100.0 %
30m
1.8 mm
6:20am 03/08/2026
6:50am 03/08/2026
1 in 1 years
100.0 %
60m
3.2 mm
6:20am 03/08/2026
7:20am 03/08/2026
1 in 1 years
100.0 %
90m
3.6 mm
6:20am 03/08/2026
7:50am 03/08/2026
1 in 1 years
100.0 %
120m
4.0 mm
6:10am 03/08/2026
8:10am 03/08/2026
1 in 1 years
100.0 %
3h
4.0 mm
6:10am 03/08/2026
9:10am 03/08/2026
1 in 1 years
100.0 %
4h
4.0 mm
6:10am 03/08/2026
10:40am 03/08/2026
1 in 1 years
100.0 %
6h
4.0 mm
6:10am 03/08/2026
12:10pm 03/08/2026
1 in 1 years
100.0 %
9h
4.8 mm
12:50am 03/08/2026
9:50am 03/08/2026
1 in 1 years
100.0 %
12h
4.8 mm
12:50am 03/08/2026
12:50pm 03/08/2026
1 in 1 years
100.0 %
18h
4.8 mm
12:50am 03/08/2026
6:50pm 03/08/2026
1 in 1 years
100.0 %
24h
4.8 mm
12:50am 03/08/2026
12:50am 04/08/2026
1 in 1 years
100.0 %
30h
4.8 mm
12:50am 03/08/2026
6:50am 04/08/2026
1 in 1 years
100.0 %
36h
4.8 mm
7:30pm 02/08/2026
7:30am 04/08/2026
1 in 1 years
100.0 %
48h
4.8 mm
7:30am 02/08/2026
7:30am 04/08/2026
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.
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