CPU temperature is not something that is exposed through the standard MS SNMP agent. There is no standard way of reading the temperature, it's different on every motherboard. Therefor, it's not something the OS can provide.
You can load extensions to the SNMP agent that makes more values available, some free, some not. For example see here: http://www.wtcs.org/informant/products.htm
. There you can find the free 'SNMP Informant - MBM Agent' that makes the values MBM collects (MotherBoard Monitor, yet another free tool) available through SNMP. Including CPU temperature.