Chimonanthus praecox is an economically important ornamental plant species native to China. It is known for its winter-season flowering times and strong fragrances. Floral fragrances vary with different circadian rhythms. Despite many studies examining the circadian-rhythm-based changes in floral fragrance, limited information is available about the floral fragrance of C. praecox with circadian rhythms. In this study, headspace solid-phase microextraction gas chromatography—mass spectrometry was used to identify the floral scent compounds in var. grandiflorus and var. intermedius from Yunnan, China. In total, 69 volatile compounds, which were largely acids, alcohols, esters, aromatic compounds, terpenes, aldehydes, and ketones, were identified and the most predominant compounds were alcohols. Compounds m-xylene, p-xylene, 2-norbornanemethanol, o-xylene, cyclohepta-1,3,5-triene, germacrene D, ethylbenzene and 3,4-dimethoxycinnamic acid contributed to the floral scent of C. praecox. While var. grandiflorus and var. intermedius flowers contained about the same number of floral scent compounds (53 and 52, respectively), their compositions varied greatly. Furthermore, hierarchical cluster analysis based on the main compounds in var. grandiflorus and var. intermedius with different circadian rhythms indicated that opened flowers had similar compounds while unopened flowers had different ones. In addition, the amounts and contents of floral scent compounds between the two C. praecox varieties were affected differently by temperature, humidity and light intensity. Our findings will contribute to the exploration of the biosynthesis and emission mechanisms of floral scent compounds in C. praecox.