I never did any internet research on this because well, what better source then the Bethesda forums right? I know the bombs began to fall about two hundred years and eight months before Fallout 3. According to M.A.R.G.R.e.T. in the Whitehouse tram system. But I noticed every single clock on the walls has the hands at 9 and 10. Did the blast cause all the clocks to stop? Every clock is at the same time.

Or this simply the development team not bothering to make working clocks and just gave us this one textured looking clock?

Sorry if this has been discussed before.

I believe it's not exactly explained. Only thing we know is that Great War happened 23 october and had lasted for about 2 hours. As for clocks, it's possible that they were purposefully set that way. Great post-apocalyptic movie "The Road" starts similar (though it's never even explained what caused apocalypse).