# astronomical seasons start
astro<-c("spring"="20-Mar-2015",
         "summer"="25-Jun-2015",
         "fall"="23-Sep-2015",
         "winter"="22-Dec-2015")

# meteorological seasons start
meteo<-c("spring"="March 1, 15",
         "summer"="June 1, 15",
         "fall"="September 1, 15",
         "winter"="December 1, 15")