Why is getline not splitting up the the stringstream more than once?

When I'm trying to read data from a file, it is not updating the value of tempString2.

Instead of grabbing and splitting the new line, it just holds the last value of the first data line.

The reason I believe that the second getline is the issue is that the data is being read in, and the loops are running the exact number of times that I need them to.

#include <iostream>
#include <fstream>
#include <string>
#include <sstream>

void PopulateWindLog(int dataIndex, std::string fileName, int const headerVecSize)
{
    std::string tempString;
    std::string tempString2;
    std::stringstream tempStream;

    // open data file
    std::ifstream dataFile(fileName);

    // skip the header line
    std::getline(dataFile, tempString);

    // while there is still data left in the file
  
    while(std::getline(dataFile, tempString))
    {
        tempStream << tempString;
        std::cout << tempString << std::endl;

        for(int i = 0; i < headerVecSize; ++i)
        {
            std::getline(tempStream, tempString2, ',');
            std::cout << tempString2 << std::endl;

            if(i == dataIndex)
            {
                std::cout << tempString2 << " INSIDE IF STATEMENT !!!! " << std::endl;
            }
            
        }
    }
}

This is the dataset that I'm using. For replication, I'm looking for column 'S' (index 10). headerVecSize is 18.

WAST,DP,Dta,Dts,EV,QFE,QFF,QNH,RF,RH,S,SR,ST1,ST2,ST3,ST4,Sx,T
31/03/2016 9:00,14.6,175,17,0,1013.4,1016.9,1017,0,68.2,6,512,22.7,24.1,25.5,26.1,8,20.74
31/03/2016 9:10,14.6,194,22,0.1,1013.4,1016.9,1017,0,67.2,5,565,22.7,24.1,25.5,26.1,8,20.97
31/03/2016 9:20,14.8,198,30,0.1,1013.4,1016.9,1017,0,68.2,5,574,22.7,24,25.5,26.1,8,20.92

This is the output that I'm getting. Output of the built program