Background: Time in headache disorders is crucial for diagnosis and gives insight into headache pathophysiology., Objective: To summarize published studies which describe timing processes in both attack presentation (onset, duration) and disease characterization (age of onset, evolution over time) in primary headache disorders and link to pathophysiology., Methods: A comprehensive search was conducted through Ovid MEDLINE(R) and PubMed, focusing on English-language articles from 1946 to 2023 to write the review. The International Classification of Headache Disorders, 3rd edition provided the framework for the review of primary headache disorders (migraine, tension-type headache and cluster headache)., Results: Attack presentation : Migraine attacks exhibit significant circadian and infradian rhythms, influenced by hormonal levels, light sensitivity, and hypothalamic activation. Tension-type headache lacks clear chronobiological patterns, with limited understanding of its underlying mechanisms. Cluster headache displays a distinct circannual pattern, with attacks often occurring at night and relevant involvement of the hypothalamus. Disease characterization : Age of onset exhibits the earliest peak in migraine; frequency and typical features of primary headache disorders decrease over time., Conclusion: This comprehensive analysis of time patterns in primary headache disorders underscores their role in phenotyping, understanding and treating primary headache disorders, offering promising avenues for advancing and tailoring headache management., Competing Interests: Declaration of conflicting interestsThe authors declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: A.G.M. reports that within the prior 36 months has received speaker honoraria from TEVA, Lilly and Altermedica.J.C.R reports in the last 36 months he has received honoraria for education presentations for Abbvie, Novartis and Viatris. He has served on medical advisory boards for Pfizer, Viatris and Lilly. His institution has received funding for research grants, clinical trials and projects supported by the International Headache Society, Brain Foundation, Lundbeck, Abbvie, Pfizer and Aeon.F.H., F.J.O., H.G., T.C.S., M.C.D., U.A., H.H., J.M.K., reports no conflict of interests.K.S.L reports personal fees from Teva and Acticor Biotech.E.C. has received received honoraria from Novartis, Chiesi, Lundbeck, Medscape.P.P.R. reports that within the prior 36 months, having received honoraria as a consultant and speaker for: AbbVie, Amgen, Biohaven, Chiesi, Eli Lilly, Lundbeck, Medscape, Novartis, Pfizer and Teva. Her research group has received research grants from Novartis, Teva, AbbVie, EraNET Neuron, RIS3CAT FEDER, AGAUR, ISCIII, International Headache Society; has received funding for clinical trials from Alder, Amgen, Biohaven, Eli Lilly, Lundbeck, Novartis, Teva. She is the Honorary Secretary of the International Headache Society. She is a member of the Clinical Trials Guideline Committee of the International Headache Society. She serves as an associate editor for Cephalalgia, Headache, The Journal of Headache and Pain, Neurologia, and Revista de Neurologia. She is the founder of www.midolordecabeza.org. P.P.R. does not own stocks from any pharmaceutical company.