Collect average from a range depending on dates

QWeelon can you describe how it worked I am facing difficulty to follow the SergeiBaklan function since my date column range depend on the available hourly records and i want to have average of wind over the day
this is my part of my data
Date                Wind(m/sec)
10/1/2010 0:00 3.61
10/1/2010 1:00 3.61
10/1/2010 2:00 1.56
10/1/2010 8:00 2.58
10/1/2010 9:00 3.08
10/1/2010 10:00 5.67
10/1/2010 11:00 2.06
10/1/2010 12:00 2.06
10/1/2010 14:00 4.64
10/1/2010 15:00 1.56
10/1/2010 17:00 4.11
10/1/2010 20:00 3.08
10/1/2010 23:00 3.61
10/2/2010 5:00 2.58
10/2/2010 8:00 2.58
10/2/2010 9:00 3.08
10/2/2010 10:00 3.08
10/2/2010 11:00 3.61
10/2/2010 12:00 1.56
10/2/2010 13:00 2.06
10/2/2010 14:00 1.03
10/2/2010 18:00 1.56
10/2/2010 20:00 1.56
10/2/2010 21:00 2.58
10/2/2010 22:00 3.08
10/3/2010 2:00 3.08
10/3/2010 6:00 2.58
10/3/2010 7:00 2.06
10/3/2010 8:00 2.58
10/3/2010 9:00 4.64
10/3/2010 10:00 5.67
10/3/2010 11:00 5.14
10/3/2010 12:00 4.64
10/3/2010 13:00 5.14
10/3/2010 14:00 1.56
10/3/2010 15:00 4.64
10/3/2010 16:00 2.58
10/3/2010 17:00 2.58
10/3/2010 18:00 3.08
10/3/2010 19:00 3.08
10/3/2010 20:00 3.08
10/3/2010 21:00 4.11
10/3/2010 22:00 3.61
10/4/2010 4:00 3.08
10/4/2010 5:00 2.58
10/4/2010 6:00 2.58
10/4/2010 7:00 3.61
10/4/2010 8:00 2.58
10/4/2010 9:00 3.61
10/4/2010 12:00 6.17
10/4/2010 13:00 1.56
10/4/2010 15:00 6.17
10/4/2010 16:00 6.17
10/4/2010 17:00 5.67
10/4/2010 19:00 3.08
10/4/2010 20:00 4.11
10/4/2010 22:00 3.08
10/5/2010 2:00 5.67
10/5/2010 5:00 4.64
10/5/2010 6:00 6.17
10/5/2010 7:00 6.69
10/5/2010 8:00 9.78
10/5/2010 9:00 8.75
10/5/2010 10:00 10.28
10/5/2010 13:00 6.17
10/5/2010 14:00 6.17
10/5/2010 15:00 5.14
10/5/2010 16:00 3.61
10/5/2010 17:00 5.67
10/5/2010 19:00 3.08
10/5/2010 22:00 3.61
10/5/2010 23:00 3.08