This is an even year, which means many transpac crossings in small boats from the US West Coast to Hawaii, sailing and rowing. We have the Victoria to Maui yacht race and the Pacific Cup yacht race and the Great Pacific Rowing Race. One issue on this summertime route is the chance of encountering a tropical storm or hurricane, together referred to as tropical cyclones (TC). The statistics for all TC in the central Pacific of HI are found at the Central Pacific Hurricane Center (CPHC), and shown in Figure 1. Data at that link ended in 2013, but we can find latest data at another link at CPHC, and I have used that data to extend the data in Figure 1.
We see a total of 212 events over a period of 47 years, which is an average of 4.5 systems per year. That is consistent with data in Bowditch, as well as updated versions of that we have in our new textbook Modern Marine Weather, 3rd ed. The CPHC includes tropical depressions in their TC counts, so a couple of these each year may not have made it to tropical storm. In 2015, for example, 2 of the 16 are depressions, not storms.
“Per year” is the same as “per season,” as these are pretty much limited to the period July, Aug, Sept, as shown in Figure 2, keeping in mind we try to avoid this crossing in later months due to increasing likelihood of bad weather from other sources.