To divide by 100, how about
send_windSpeed = send_windSpeed / 100;
You said you're getting integers. So, in your code
send_windSpeed = thingSpeakRead(readChannelID, 'ReadKey', readAPIKey);
send_windSpeed = send_windSpeed/100;
is send_windSpeed integer or floating point after the first line of code where you call thingSpeakRead()? The second line should not change it from floating point to integer.
To multiply by 100, you simply use * instead of /, like this:
send_windSpeed = send_windSpeed * 100;
Please reply as a comment to this (my) answer, not as a brand new answer to your original question.