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Light mode 5:20am 13/07/2026 to 5:20am 15/07/2026
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
0.0 mm
5:20am 13/07/2026
5:30am 13/07/2026
1 in 1 years
100.0 %
20m
0.0 mm
5:20am 13/07/2026
5:40am 13/07/2026
1 in 1 years
100.0 %
30m
0.0 mm
5:20am 13/07/2026
5:50am 13/07/2026
1 in 1 years
100.0 %
60m
0.0 mm
5:20am 13/07/2026
6:20am 13/07/2026
1 in 1 years
100.0 %
90m
0.0 mm
5:20am 13/07/2026
6:50am 13/07/2026
1 in 1 years
100.0 %
120m
0.0 mm
5:20am 13/07/2026
7:20am 13/07/2026
1 in 1 years
100.0 %
3h
0.0 mm
5:20am 13/07/2026
8:20am 13/07/2026
1 in 1 years
100.0 %
4h
24.2 mm
8:10am 14/07/2026
12:40pm 14/07/2026
1 in 1.2 years
84.94 %
6h
24.2 mm
6:40am 14/07/2026
12:40pm 14/07/2026
1 in 1.1 years
87.92 %
9h
24.2 mm
3:40am 14/07/2026
12:40pm 14/07/2026
1 in 1.1 years
90.72 %
12h
24.2 mm
12:40am 14/07/2026
12:40pm 14/07/2026
1 in 1.1 years
92.62 %
18h
24.2 mm
6:40pm 13/07/2026
12:40pm 14/07/2026
1 in 1.1 years
95.17 %
24h
24.2 mm
12:40pm 13/07/2026
12:40pm 14/07/2026
1 in 1.0 years
95.91 %
30h
24.2 mm
6:40am 13/07/2026
12:40pm 14/07/2026
1 in 1.0 years
96.46 %
36h
24.2 mm
5:20am 13/07/2026
5:20pm 14/07/2026
1 in 1.0 years
96.91 %
48h
24.2 mm
5:20am 13/07/2026
5:20am 15/07/2026
1 in 1.0 years
97.53 %
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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