The Digital Thermo Hygrometer from AgroLab is a digital, portable instrument for controlling the temperature and humidity of your room.  
Further includes a sensor that even allows you to measure the temperature of two places simultaneously. The additional sensor can also be used to measure your nutrient solution temperature. 
It has the ability to record in memory the higher and lower temperature-humidity, so you know what's happening in your room while you are away.  
It can be measured in centigrade (°C) and Fahrenheit (°F).

AgroLab Thermo/Hygrometer