Officially 13.48 inches was recorded at the Boone 1SE weather station, just missing the all time May mark of 14.89 recorded in May 2017.
18 out of 31 days recorded measurable precipitation.
The greatest amount in a 24 hour period at the Boone 1Se reporting station was 3.40 inches between 6am Friday May 18 and 6am Saturday May 19, followed by 2.12 inches between 6am Tuesday May 29 and 7am Wednesday May 30.
The bulk of the rain for the month fell 6 of the last 15 days totaling 10.51 inches.
The all time monthly mark for rain is 18.15 inches, set in July 2013. For more information about rainfall that month see this link and this link. For historical purposes it is worth noting that there are no weather records for year 1948.
For the yearly totals, as of May 31, it is the fourth wettest year at 32.43 inches, trailing 1998 at 39.94, 2017 at 35.17 inches and 2013 at 32.98.
*In keeping track of weather records it’s important to note that records for Boone have been kept by two different official weather stations for precipitation. The reporting station from 1929 to 1980 has some years with incomplete/missing data which could mean much higher totals. As an example 1940, the year of the great flood, yearly totals only show 56.97. 77 days of data are missing for that year. The Boone 1Se reporting station is the current official station and has been recording data since June 1980.*
Observed rainfall in the High Country, North Carolina and the nation for May 2018. Graphics: National Weather Service
Other note-able wettest and warmest months: