How to calculate th mean/average value for a repetetive time step

I have a daily temperature Data frome 1951 to 2005.

i want to create a loop to calculate the mean value of the temperature each Dt =20 days from 1 Jan 1951 to 31 Dec 2005 and plot it. ( the mean value will be plotted in the middl of Dt).

The main objective is to get a plot like the photo attached.

clear all
    close all
    clc
    % NAME OF THE PROJECT %%
    
    %%%%% PLACE %%%%
    
    %  TEMPERATURE MODEL 3.5 HISTORICAL
    
    Temperature = xlsread("File name", "B3:B12786" ); %import temperature data
    writematrix(Temperature, 'Temp.txt');
    Temp= readmatrix("Temp.txt");

    % create the timetable [DD MM YYYY]
    
    year0=1971; 
    temps=timetable(Temp,'RowTimes',datetime(year0,1,1:height(Temp)));

for i = 1 : length (Temp)
% .... ???

end

My data is then represented like this :

Variable Near-Surface Air Temperature

Datetime Number

Unit Degree Celsius

01-janv-1951 1.0442

02-janv-1951 2.0769

03-janv-1951 9.1496

04-janv-1951 6.8813

.

12-mai-1999 11.3024

13-mai-1999 12.6448

14-mai-1999 13.0754

.

.

Figure source: Climate Impacts Group, based on climate projections used in the IPCC 2013 report.

Answer 1

[Jon]

You should be able to use MATLAB's movmean https://www.mathworks.com/help/matlab/ref/movmean.html for this without any loops