May 2010 was not the warmest on record, but it did continue the string of above normal temperatures that began in Jan. and included two months - Mar. and Apr., which were the warmest on record. The above normal temperatures caused trees to leaf out and flower early, which led to brown leaves and damaged fruit as the temperatures plunged to 24 degrees on the May 11, with some areas reporting snow.
The average high temperature was 71.8 and the average low temperature was 46.2 degrees, giving us an average of 59.0 degrees - 4.2 degrees above normal and the second warmest on record. The warmest May was in 1991 when the average was 59.5 degrees and the coldest May was in 1997 when the average was 49.6 degrees.
The coldest temperature, of 24 degrees was recorded on May 11 and the warmest temperature of 93 degrees was recorded on May 27. This was the warmest day on record for May. The previous warmest day in May was 90 degrees, recorded three times in 1986, 1992 and 2007. There were 227.5 degree days, bringing the seasonal total to 7266.5.
Rainfall was 3.09 inches - 0.71 inches below normal. Rain fell on 11 days with the greatest amount of 0.95 measured on the 8th. Most of the precipitation fell in the first half of the month leading to very dry conditions at the end of the month. There was some snow in the area on May 10 and 11, but not in Riparius.
The river reached its highest level of 4.56 feet on May 10 and its lowest level of 2.67 feet on May 31. This low level shows how dry it became at the end of the month as the rapidly growing vegetation and the lack of significant rainfall produced very dry conditions.