Product review (5 stars): Extech 445815 is quick to adjust and accurate
I just purchased the Extech 445815 and took the meter outside after opening it.  Weather channel has us at 48F 22% humidity and dew point at 11F.  Within a minute or two, the extech showed temp at 47.1F 24% humidity and dew point at 11F.  I bought an Accu-rite 39 dollar model from local store a week earlier and stuck the outdoor sensor next to the base unit and they could not agree on temperature by 5 degrees so I took it back and got the extech.  Nice display.