Hi,

This is my first time working with precipitation data. I received a dataset with 15 minute data and a daily dataset. I need them both to be 24 hour data.

See two examples:
Example 1: Current setup is TWO columns, one date and one column of 15 minute values

date precipitation 15 minute (cm)
9/21/2012 20:00 0
9/21/2012 20:15 0
9/21/2012 20:30 0
9/21/2012 20:45 0
9/21/2012 21:00 0
9/21/2012 21:15 0
9/21/2012 21:30 0
9/21/2012 21:45 0
9/21/2012 22:00 0
9/21/2012 22:15 0
9/21/2012 22:30 0
9/21/2012 22:45 0
9/21/2012 23:00 0
9/21/2012 23:15 0
9/21/2012 23:30 0
9/21/2012 23:45 0
9/22/2012 0:00 0
9/22/2012 0:15 0
9/22/2012 0:30 0
9/22/2012 0:45 0
9/22/2012 1:00 0
9/22/2012 1:15 0
9/22/2012 1:30 0
9/22/2012 1:45 0
9/22/2012 2:00 0
9/22/2012 2:15 0
9/22/2012 2:30 0
9/22/2012 2:45 0
9/22/2012 3:00 0
9/22/2012 3:15 0
9/22/2012 3:30 0
9/22/2012 3:45 0
9/22/2012 4:00 0
9/22/2012 4:15 0
9/22/2012 4:30 0
9/22/2012 4:45 0
9/22/2012 5:00 0
9/22/2012 5:15 0
9/22/2012 5:30 0
9/22/2012 5:45 0
9/22/2012 6:00 0
9/22/2012 6:15 0
9/22/2012 6:30 0
9/22/2012 6:45 0
9/22/2012 7:00 0
9/22/2012 7:15 0
9/22/2012 7:30 0
9/22/2012 7:45 0
9/22/2012 8:00 0
9/22/2012 8:15 0
9/22/2012 8:30 0
9/22/2012 8:45 0
9/22/2012 9:00 0
9/22/2012 9:15 0
9/22/2012 9:30 0
9/22/2012 9:45 0
9/22/2012 10:00 0
9/22/2012 10:15 0
9/22/2012 10:30 0
9/22/2012 10:45 0
9/22/2012 11:00 0
9/22/2012 11:15 0
9/22/2012 11:30 0
9/22/2012 11:45 0
9/22/2012 12:00 0
9/22/2012 12:15 0
9/22/2012 12:30 0
9/22/2012 12:45 0
9/22/2012 13:00 0
9/22/2012 13:15 0
9/22/2012 13:30 0
9/22/2012 13:45 0
9/22/2012 14:00 0
9/22/2012 14:15 0
9/22/2012 14:30 0
9/22/2012 14:45 0
9/22/2012 15:00 0
9/22/2012 15:15 0
9/22/2012 15:30 0
9/22/2012 15:45 0
9/22/2012 16:00 0
9/22/2012 16:15 0
9/22/2012 16:30 0
9/22/2012 16:45 0
9/22/2012 17:00 0
9/22/2012 17:15 0
9/22/2012 17:30 0
9/22/2012 17:45 0
9/22/2012 18:00 0
9/22/2012 18:15 0
9/22/2012 18:30 0
9/22/2012 18:45 0
9/22/2012 19:00 0
9/22/2012 19:15 0
9/22/2012 19:30 0
9/22/2012 19:45 0
9/22/2012 20:00 0
9/22/2012 20:15 0
9/22/2012 20:30 0
9/22/2012 20:45 0
9/22/2012 21:00 0
9/22/2012 21:15 0
9/22/2012 21:30 0
9/22/2012 21:45 0
9/22/2012 22:00 0
9/22/2012 22:15 0
9/22/2012 22:30 0
9/22/2012 22:45 0
9/22/2012 23:00 0
9/22/2012 23:15 0
9/22/2012 23:30 0
9/22/2012 23:45 0

Example 2: This is how I need the above dataset to look. Two columns but DAILY (24 hours) not 15 minute data.
date precipitation 24 hour (cm)
9/21/2012 0
9/22/2012 0.01
9/23/2012 0
9/24/2012 0
9/25/2012 0
9/26/2012 0
9/27/2012 0
9/28/2012 0.8
9/29/2012 0.48


Can anyone help with an excel formula to convert 15 minute data (example 1) to daily data (example 2)? If possible please give a little information on how the equation works as I prefer to understand why things work since my formulas kept failing. I would prefer not to do it manually as I have 700 days to do.

Thank you!