There isn't a specific type of thermometer used for hydroponics. Digital thermometer can get expensive, though $10 isn't bad at all for a digital one. Though just like with anything electronic it may eventually give false readings. I personally just use a small standard glass fish tank thermometer I got at wal-mart for $1.97. I just tie string around the suction cup and toss it in the reservoir for a couple minutes to check temp.
16% humidity?? Wow, that's extremely low. My weather station won't even register anything below 20%. Like daytonajim00 mentioned most people start
seeds in some kind of seed tray with a clear plastic cover. The plastic cover holds in the humidity. As the water evaporates inside, it creates humidity, and the lid holds it in. So regardless of what the outside humidity is, inside the tray stays around 80% to 90% humidity. But you can use just about any covered container. As long as the top lets the light in. Though you should open it up once in a while so the plants can get fresh oxygen from time to time.