You can change the date & time format in Google Sheets & Excel Online using this guide. Use different date & time formats in spreadsheets.

How to Auto-Format the Date in MS Excel. When you create Microsoft Excel spreadsheets that contain one or more columns of dates, you can make things a bit easier if you pre-format your cells to ...

Excel for the web now supports conditional formatting, and the interface is easier to use than the desktop edition. Susan Harkins shows you how to use it.

Conditional formatting highlights key information in a spreadsheet so it’s easy to see at a glance. This beginner’s guide gets you started using conditional formatting.

The problem is that the minimum bounds are represented by a number, and the dates here are using the Short Date format. Luckily, Excel allows us to easily convert dates into their numerical values.