Charlotte Bronte creates many different moods throughout the story of Jane Eyre. Primarily, it is in her descriptions of setting and characters that mood is created.
From the very beginning of the story, when Jane is locked in the Red Room at Gateshead, Bronte's descriptions contribute to an overall somber mood - though here the mood is meant to be ominous and foreboding. For example, Bronte writes that Jane became "cold as a stone" and that she believes she saw a ghost - "I thought the swift-darting beam was a herald of some doing vision from another world" (page 19, 21). Jane's being physically and emotionally uncomfortable lends itself to the created mood.
Jane's time at Lowood is also peppered with dismal descriptions that create a somber mood. For instance, the girls who live there look plain and sickly - their uniforms "suited them ill, and gave an air of oddity even to the prettiest" (page 56). The setting is similarly dim - "all was wintry blight and brown decay" (page 58). The lack of colour and abundance of description about the disciplinary measures at Lowood provide a depressing mood for this section of the story.