1999 Total Eclipse: Plot of Light Levels at Carn Brea, Cornwall

You'll see that:-

• Cloudy skies or no, light levels stay more or less unchanged until a few minutes before totality, when things happen fast and there is a large decrease in light for the duration.
  
  
• Totality is a completely different experience to near totality. Even a few miles from the path of the moon's shadow you will not experience the drop in light level and all the effects of a total eclipse. It follows that if you are interested in the experience of an eclipse and can move, it's well worth it ...

Thanks to Angus Gregson who provided this data.

Link to Narrative

All before you, in this world, is smoke and shadows.