Comment 3 for bug 757195

type in the terminal:
python or python2.6 or python2.7 (depending on which python version you have...)

then in the python shell type:
import gi
and press <ENTER>

you get something like that:

artem@linux-void:~$ python
Python 2.7.1+ (r271:86832, Mar 24 2011, 00:37:39)
[GCC 4.5.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import gi
>>> import gi.repository
>>>

type exit() to quit the shell

if you get something like this:
>>> import this_module_definitely_does_not_exist
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ImportError: No module named this_module_definitely_does_not_exist
>>>

instead of an empty >>> line (right after import gi and gi.repository) — then you have missing module(s) — try to install python2.7-dev

p.s. it's not indicator-weather issue, it's your python :)