I ran the linear regression for DC annual snowfall.  Using 1888 as the starting point, the equation is: Annual snowfall in DC = -0.07 X # of years past 1888 + 22.9 So, on average DC is seeing 0.07" less snow per year since 1888.  The R squared value is 6%, which means that 6% of the variability from year to year is a function of the passing of time.  Another way to look at this number is that 94% of the variability from year to year is random.   Using 1969 as the startin