string html;
//(Some code that reads into a big string)

string delimiter( "<p class="wx-temp">" );
vector<int> temperatures;

size_t pos = html.find_first_of(delimiter);
while( pos != string::npos )
{
    // Skip past the tag (to the temperature)
    pos += delimiter.size();
    if( pos >= html.size() ) break;

    // Extract it (C-style) and chuck it into the vector.
    int temperature = atoi( html.c_str() + pos );
    temperatures.push_back(temperature);

    // If you want to stop after the first 10:
    if( temperatures.size() == 10 ) break;

    // Find the next tag
    pos = html.find_first_of(delimiter, pos);
}