The DHT-series of sensors are all for measuring temperature and humidity. The best is the DHT22 and the worst is DHT11 that is nearly obsolete by now and probably only sold as part of large "starter kits".

The DHT11 cannot do negative temperatures, for example, such that its application is fairly limited. Similarly, the DHT11 has a resolution of , which is not too great. The DHT22 does not have such limitations; it can measure negative temperatures and it also has a very small defined error. Fortunately, the price is more or less the same.