Average monthly temperatures, 1949-1988

SUMMARY:
       The raleigh.temp data set has 480 rows  and  3  columns.
       Each  year  has  12 rows of data, one for each month.  The
       measurement is likely to be the  average  of  the  average
       daily  temperature,  where the average daily temperature =
       (daily high+daily low)/2.

DATA DESCRIPTION:
       This data frame contains the following columns:
temp:     = (daily high+daily low)/2.
month:
year: