you can run a linear regression of the number of home runs hit (1) on a constant and the wind speed (2) and the wind direction (3). However, a strong wind blowing to N has the converse effect from a wind blowing to S. Therefore, you might transform the data to a two variable case:
Change the wind direction in angle phi. Let phi=0 for N, and compute
wind speed to N = (wind speed)*cos(phi)
Now you can compute the Pearson correlation of (i) the windspeed to N and (ii) number of home runs hit. Alternatively you can run a linear regression of (ii) on (i) and a constant to do a test of significance.