An almanac is a book published annually giving statistical information on various subjects. Underpinned by the theories of CL and SFL, this study adopts both qualitative and quantitative analysis with a contrastive approach to full or sample texts, on the level of lexicogrammar, three metafunctions and genre stratum respectively, to see to what extent Chinese and American local comprehensive almanacs are similar or different in dealing with equivalent information through the same genre. Based upon the empirical data we have collected of local materials and copies of American almanacs, it is found that the genre of almanac, as a kind of reference book, conditions the ideational metafunction in fundamental objectivity, the interpersonal metafunction in objectivity and straightness, and certain lexicogrammatical features in objectivity, detachment, result-orientation, economy and accuracy. Combining the three lines of inquiry, we can see that genre is positioned as an abstract level of analysis coordinating field, tenor and mode (known collectively as register), and register is realized in turn through language (discourse semantics, lexicogrammar, etc). Both show the linguistic features of almanac as detached, result-oriented, economical and accurate. However, due to the linguistic conventions, social and cultural differences, Chinese and American almanacs have rather observable distinctions in generic structure. It is believed that the present study can bridge the gap between linguistics and almanacs, and pave a new way for the development of both CL and SFL, and almanac studies.