Total precipitation averaged across the 48 contiguous U.S. states from January to July, 1895-2019. Graphic: NOAA / NCEI
Total precipitation averaged across the 48 contiguous U.S. states from January to July, 1895-2019. Graphic: NOAA / NCEI

By Bob Henson
7 August 2019

(Weather Underground) – The Big U.S. Wet of 2018-19 went on cruise control in July, but the year so far managed to hang on as the nation’s wettest calendar year to date in records going back more than a century, NOAA reported on Wednesday. Averaged across the 48 contiguous states, the month of July saw 2.69” of precipitation, which is just below the 20th-century average of 2.78”.

The period from August 2018 to July 2019 came in just shy of the wettest 12-month period on record. Below is the new list of the top-ten wettest 12-month spans in U.S. records going back to 1895. Amazingly, the seven wettest spans among all of the 1495 overlapping year-long spans since January 1895—and eight of the ten wettest—have occurred in the last five years. Even given the fact that a very wet span of a few months will be factored into such listings more than once, this is still remarkable testimony to the power of our warming climate to make extreme rain events even more extreme. […]

Statewide rankings for average precipitation in the U.S. for July 2019, as compared to each July since records began in 1895. Darker shades of green indicate higher rankings for moisture, with 1 denoting the driest month on record and 125 the wettest. Image credit: NOAA / NCEI
Statewide rankings for average precipitation in the U.S. for July 2019, as compared to each July since records began in 1895. Darker shades of green indicate higher rankings for moisture, with 1 denoting the driest month on record and 125 the wettest. Image credit: NOAA / NCEI

How likely is it that 2019 will be our wettest calendar year on record?

Given the head start it already has, 2019 has a reasonable chance of breaking the wettest-calendar-year record of 34.96” from 1973.

—The 20th-century average for August is 2.62”, and if this month comes in right at that amount, then the Jan-Aug total will exceed the record of 24.23” set in 2017.

—The average for September is 2.49”, so if both August and September were to match their 20th-century averages, then the year to date will end up above the record of 26.50” set in 2017. [more]

U.S. Racks Up Wettest Calendar Year to Date