Step-by-step explanation:
I could not find the passage that is missing in your question so I cannot tell you the appropriate answer but I will try to help you in some sort of way.
When writer are using weather condition is usually has to do something with the tone or future events in the text. For example, If the weather is moody or it starts to rain all of the sudden, then it brings to the text mysterious mode because readers are knowing that something will happen and they are waiting to find out what is it.
In other examples we are having sunny, snowy, windy weather conditions and more. Usually, when in the text we can see sunny weather then it is giving us kind or benign tone in the text so because of it we are assuming that some good event will happen in the future.