Great Expectations Forecast: Monday—rainy and dark. Tuesday—rainy and windy. Wednesday—rainy and rainy. Thursday—stormy. Friday—misty (thick fog warning). Saturday—heavy mist with light showers. Sunday—windy. Want it in Dickens's own words?
It was wretched weather; stormy and wet, stormy and wet; and mud, mud, mud, deep in all the streets. (39.4)
You get the point. We rarely see the sun, and when we do, we don't quite know what to do with ourselves. What's more, whenever there happens to be severe weather, something always happens. For example, the night Magwitch arrives on Pip's doorstep, there's a HUGE storm outside that only gets worse in the morning. When Pip first meets the convict in the graveyard, the mists are so thick that Pip can barely see his hands. It seems to us that weather is very closely tied to plot, and that it has something to do with big moments in Pip's life.