How to Fill Missing Rainfall Data

**jonny777** · 06-09-2022, 03:10 PM

hey every one in this group i need help on how to fill a missing rainfall data using the RF filling methods and to select the best method for the fill

**AliGW** · 06-12-2022, 01:27 AM

Welcome to the forum.

There are instructions at the top of the page explaining how to attach your sample workbook.

A good sample workbook has just 10-20 rows of representative data that has been desensitised. It also has expected results mocked up, relevant cells highlighted and a few explanatory notes.

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**curiouscat408** · 06-12-2022, 10:03 AM

Not really an Excel question. And the correct answer might depend on the available data, the number of missing data points, and the size of those gaps.

The Excel answer might depend on how automated you want the solution to be.

Generally, the simplest approach (but necessarily the most accurate) is to do a linear interpolation between adjacent available data points.

For example, if you have data in E1 and E5 with corresponding dates in D1 and D5, enter the missing dates in D2:D4 and enter formulas of the following form into E2:E4 (E2 for example):

=FORECAST(D2, CHOOSE({1,2}, $E$1, $E$5), CHOOSE({1,2}, $D$1, $D$5))

Normally, the FORECAST function (and similar functions like TREND and LINEST) interpolates an approximate linear regression line when there are multiple data points.

But it does an exact interpolation of the actual line when there are only two data points.