Sumifs using dates help

Hi Forum,

I dont understand why my formula isnt working, its really simple im missing something.

Here is what im trying to do ...My rain gage recorded many times per day making many entries, and i need to sum them up so they just use one row for each day with summed up amount rained.



I have my spreadsheet attached, please help.

Column K is where the accumulated rain for each day should be placed, or the sumif formula that is supposed to be working..