If you need a standalone temperature logger then I recommend the EL005 (datalogger) with an EL001 (temperature converter) and an EL015 (temperature sensor). We sell an EnviroMon starter kit which includes all of this.
The enclosure of the EL005 and EL001 is not IP65 rated so you will have to put them in your own boxes. The interface for the EL005 to the PC is RS323, the interface between the EL005 and EL001 is NOT RS422/485 although it is similar in operation. The EL005 has internal rechargable batteries as well as a DC power suppy.
If you email me your address I can send you some literature.