If you are using new ribbon interface you can go to the Formulas tab Calculation group click on Calculation Options and from the drop-down menu select Automatic. Tomorrow the formula will automatically update to tomorrows date. When the manual calculation mode is enabled you will need to press F9 on your keyboard to force formulas to recalculate.
The NOW function updates to the latest date and time whenever Excel recalculates the worksheet.
To make your formulas automatically update go to Excel Options Formulas Workbook calculation and set the calculation to Automatic. To update Excel spreadsheets with data from another spreadsheet just follow the points given below which will be applicable for the Excel version 2019 2016 2013 2010 2007. On the Excel ribbon go to the Formulas tab Calculation group click the Calculation Options button and select one of the following options. SERIES Sheet1DateSheet1Temperature1 The chart will update automatically each day.