April Showers

We all know the phrase "April showers bring May flowers", but how do April showers compare to other months? Of the 35 major climate sites, only Bridgeport, CT calls April its wettest month (based on 1981-2010 normals). “July showers” may be a more accurate phrase as it is normally the wettest month at 17 of the major climate sites.

Based on 1981-2010 normals, the wettest months for each of the 35 major climate sites compared to normal April precipitation.

If we look at the all-time wettest month on record at each of the major climate sites (based on each site’s period of record), none of them were April. August was the all-time wettest month at 18 sites, though.

Based on each site’s period of record, the all-time wettest month on record.

Even if we look at all-time wettest days on record, April only appears twice (Beckley, WV, and LaGuardia Airport, NY). August leads with 12 sites having their all-time wettest day during that month.

Based on each site’s period of record, the all-time wettest day on record.

Why do July and August top the lists so often? One reason is convective showers and thunderstorms, which can dump heavy rain in a short period of time and occur frequently in these months. Tropical cyclones (and their remnants) also contribute.

Radar estimated rain totals from Hurricane Irene, which contributed to August 2011 being the all-time wettest month on record at six sites. Credit: NOAA.