RAINFALL RETURN PERIOD - SAN FRANCISCO

SAN FRANCISCO
Storm Return Periods

Maximum Rainfall For Indicated Number Of Consecutive Days

Days	1	2	3	4	5	6	8	10	15	20	30	60	W-YR
RP Yrs.
2	2.06	2.62	2.96	3.28	3.57	3.81	4.31	4.79	5.73	6.48	7.61	11.52	20.95
5	2.90	3.78	4.26	4.69	5.06	5.40	6.06	6.67	7.90	8.91	10.47	15.66	27.40
10	3.47	4.57	5.14	5.64	6.03	6.44	7.21	7.85	9.23	10.40	12.25	18.10	31.13
25	4.17	5.56	6.25	6.81	7.23	7.73	8.62	9.28	10.80	12.15	14.36	20.91	35.38
50	4.68	6.28	7.05	7.66	8.10	8.65	9.64	10.30	11.89	13.37	15.86	22.85	38.28
100	5.17	6.98	7.84	8.49	8.93	9.55	10.62	11.28	12.94	14.54	17.29	24.67	41.00
200	5.66	7.68	8.62	9.31	9.76	10.42	11.59	12.23	13.94	15.66	18.68	26.41	43.57
500	6.27	8.56	9.61	10.33	10.78	11.52	12.80	13.39	15.32	17.20	20.58	28.71	46.88
1000	6.76	9.26	10.39	11.15	11.61	12.40	13.77	14.36	16.17	18.15	21.75	30.21	49.14
10,000	8.29	11.48	12.87	13.72	14.17	15.14	16.79	17.26	19.17	21.50	25.93	35.24	56.45

Special thanks to Jim Goodridge for this updated dataset of his original work: J. D. Goodridge, based on Goodridge, J. D. (1982). Rainfall Depth-Duration-Frequency for California, California Department of Water Resources, Sacramento.

A detailed explanation of return period calculations can be found in Goodridge (1982) or Historic Rainstorms in California, A Study in 1000 Year Rainfalls (California Department of Water Resources, August 1997).

W-YR = Water year (i.e., October 1 through September 30), = Return Period

EXAMPLE: A 5 day - 100 Year storm (i.e., 5 consecutive days of rain) with a return period of 100 years would statistically be 8.93 inches.

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