How to plot the mean value of each year in one point only ( EACH 1st july ) ?

Hello ,

i have daily temperature data ( 2006 - 2100)

i want to plot the yearly temperature value only in one point which is each 1st july (of each year) how can code that please ?

Thank you !

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Here is my code

%% Temperature Model 85 Rcp
clear all
close all
clc

Temperature85 = xlsread("filename.xlsx","Rcp85", "B3:B34700" ); %import data
writematrix(Temperature85, 'Temp85.txt');
Temp85= readmatrix("Temp85.txt");
year0_85=2006; % srtarting year
temps85=timetable(Temp85,'RowTimes',datetime(year0_85,1,1:height(Temp85))); % time table for daily temperature data
yearlyavg85 = retime(temps85, 'yearly', 'mean');  % calculate the mean temperature for each year
t85=temps85;
%extract years 
t85.Year = year(temps85.Time,"iso"); 
yearlyavg85.Year = year(yearlyavg85.Time,"iso");
[t85.Year] = ymd(t85.Time);
[yearlyavg85.Year] = ymd(yearlyavg85.Time);
% ymd time , mean temperature for each year
t85 = join(t85,yearlyavg85,'Keys',{'Year'}); 

% GRAPH
figure(1)
plot(t85.Time,t85.Temp85_yearlyavg85,'-r','DisplayName','yearly_Temp_Rcp85'); % plot yearly temperature all over the year
%?????????????
%Plot the mean value of each year in one point 1st july only ??????

Answer 1

[dpb]

Looks like a lot of extra work going on here--without the actual file we can't tell for sure, but one would presume the dates are in column A if the temperature data is column B...

Temperature85 = xlsread("filename.xlsx","Rcp85", "B3:B34700" ); %import data
writematrix(Temperature85, 'Temp85.txt');
Temp85= readmatrix("Temp85.txt");
year0_85=2006; % srtarting year
tT85=readtimetable("filename.xlsx",'Sheet',"Rcp85",'Range','A:B','NumHeaderLines',3,'ReadVariableNames',0);
tYA85=retime(tT85,'yearly','mean');
tYA85.Properties.VariableNames={'Year','AvgTemp'};      % set a known variable name
tYA85.Year=datetime(year(tYA85.Year),7,1);               % set the wanted date in each year - retime uses first
plot(tYA85.Year,tYA85.AvgTemp,'-r','DisplayName','yearly_Temp_Rcp85');

Even if the guess about the file format isn't quite right, it's the general approach -- there's no need for all the intermediate steps; import the data directly however it is written.

The date for the average in the output file from retime is the first date in the time period by default; I don't recall having seen an option to change it. But, it's simple enough to just set a given month,day for the year as above. I just replaced the default time variable; you can add another if want/need both for some reason, of course.