Averaging cells in one column based on date of another column in Excel 2010

I have searched high and low on the internet and still can't find a solution to what seems to be a simple issue so I am here hoping someone will enlighten me.

I have a table(not pivot) in Excel 2010 and I need a formula that will calculate the average of a group of cells in column B based on the date in column A and display it in column C but only on the first line of the date(s). Columns A and B are static. Only column C needs a formula.

Thanks in advance for any ideas.

Here is what I want the table to look like when calculated:

https://stackoverflow.com/questions/67310109/averaging-cells-in-one-column-based-on-date-of-another-column-in-excel-2010 April 29, 2021 at 10:06AM