Wyoming.
In the US there are many states that have no nuclear plants, Colorado, Nevada, New Mexico, Utah, and so on. (I am talking about nuclear power plants, not research facilities). See the NRC website www.nrc.gov for maps and details.
Japan has nuclear power plants but no nuclear weapons
No. As of 2012, there are no nuclear power plants located in the state of Montana.
Yes, Pakistan is a nuclear state, and it is growing its nuclear arsenals day by day.
Nuclear Power can be used in any weather conditions
There is only one nuclear power plant in Vermont, which is the Vermont Yankee plant in Vernon. Vernon is in the southeast corner of the state.
Which country/state is it in?
Yes, both in power generation and weapons.
Australia, New Zealand, and Italy use zero nuclear power
The first Indian nuclear power plant was at Tarapur, Maharashtra state. I don't have any information on who was in charge of it.
Colorado is a state in western USA