Arduino Operation Specifications

Although the Arduino is designed to be a prototyping board, can it actually be used as the main implementation?

Specifically, what I want to know is:

  • Is there a temperature range of operation?
  • Can the Arduino be kept on for weeks (up to a month, for example) at a time?

Yes to all questions.
Temperature is normal commercial range of 0 to 70C although I would not run it in a hotter environment than 50C