2017 kept 955 out of 987 stations sufficiently active (300 daily observations per year) to be included in this analysis. The final tally of stations with 20-yr daily precipitation extremes translated into a total of 17.5% for the year, narrowly beating out 2016, and second only to 2008 in the 117-year record. This strengthens a national upward trend that has kept the seven “wettest” years from 1990 onwards, and five of those during the last decade years, including and unprecedented THREE in a row since 2015 (2008, 2010, 2015, 2016, and 2017). The upward trend since 1901 is highly significant (p=99.99%) and amounts to an increase of 4.5% over a century (all trends computed through 2016).

There were again large regional differences: the Ohio valley recorded a whopping 27.7% (second only to 2008), confirming a highly significant (p=99.99%) annual trend that amounts to about 6%/century; the Midwest came in 19.3% (10th), consistent with its upward trend of 6.2% per century (p=99.99%); the Southeast almost repeated its previous extreme year with 20.0% (10th), slowly increasing the likelihood that its upward trend of +3%/century is significant (p=88%); the South was extreme for the third year in a row (19.0%), continuing its upward trend of +5.6% per century (p=99.99%), and the Northern Rockies ended up with a 9th ranked 15.7% (upward trend of 2.2%/century has now reached p=95%). On the other hand, there was not a single region with exceptionally low counts.