I have to say home depot. I went to walmart and the people had no idea what I was talking about when I said digital thermometer/hydrometer called an acurite. The lady sent me to like a hardware/plumbing section. Then I looked in the outdoor section and couldnt find it.

Home depot took me like less then a minute to find (right out side in the outdoor section, right next to the door) and it was like $15 or something.

It has, Temp, Humidity, Probe temp.
Its set with a temp and clock but you can take off the clock and put on the probe temp and humidity instead. It uses batterys too.