Even if we try the code below just for a one year(without using getdata function), data does not start from January!
myToken = "dHsFHwpJjKwcKvgEWfcwoUmzbqYrdGCc";
Initial_URL = "https://www.ncei.noaa.gov/cdo-web/api/v2/data?datasetid=GHCND&stationid=GHCND:SPE00119783&startdate=2006-01-01&enddate=2010-12-31&limit=1000&datatypeid=TAVG";
opt = weboptions('KeyName','token','KeyValue',myToken);
Data=webread(Initial_URL,opt);