Although it's possible to monitor data captured via an Arduino-connected sensor with a PC, directly manipulating it in real time can be an issue if your programming skills are lacking. However an interesting example has been published by Arduino forum member alina who demonstrates how to read the data from a DHT22 temperature/humidity sensor connected to an Arduino via python on a PC. Doing so gives you the framework to understand how python code and capture Arduino serial data, and then work with it to meet your requirements.
If you're looking for a sensor to measure temperature and humidity - check out our HUMID: humidity and temperature sensor module. Designed around the DHT22 sensor, it only requires one digital pin and power - and is easy to use with out Quick Start guide. With a temperature range of -4°C to +125°C with +/-0.5°C accuracy, and humidity at 0-100% with 2-5% accuracy you're ready to measure. For more information and to order, click here.