What Xbee should I buy?

I need the help of someone more experienced with Xbee, I don’t want to take advantage of your kindness but I’m a bit lost.

I want to develop a small project with digi xbee mesh nodes (15 aprox), the idea is to create a WSN network whom must bee able to measure the temperature with high accuracy (± 0.1ºC).
I have been testing with the mesh development kit and all seems to work well but some doubts have been arised about the best module to solve certain problems.

The type of node that I’ve choosen is xbee s2c, and these are my conclusions.

  • Distance range is more than enough
  • Power consumption is good.

Things that are not so good and perhaps someone could share your experience.

  • There aren’t analog temp sensors with that level of accuracy…I’m thinking in use thermistors (I suposse that If If would like to use digital sensor I should use an intermediate micro, arduino class or similar)
  • The synchronization of the data sending is not good enough…over the time, nodes go out of sync.

What is the device that could best fit the project?
Thanks in advanced.