So far, the 2018-2019 rainfall season has been pretty dry, with only 0.21” having fallen in downtown San Francisco. But it is far from the driest, with 26, out of 169 previous July 1st to October 31st totals having lesser amounts.
Looking at the 47 seasons that ranged from 0.00” to 0.42” for teh first 4 months of the rainfall season: 25 (53%) ended with less than 80% of normal by June 30th, 15 (32%) ended with between 80% and 120% of normal, and 7 (15%) of the seasons finished with more than 120% of normal.
It is interesting to note that both San Francisco’s all-time driest and wettest seasons began dry. The driest was 1850-1851 with a July to October total of 0.33” and a final seasonal total of just 7.42”. Conversely, 1861-1862, after having only 0.02” through October, finished with a fantastic (except for the flooding) record season of 49.27”.
List of the 48 driest beginnings to the SF rainfall season:
