Please use this link to access this publication. Abstract Background Prevalence of cannabis use has been increasing among select subgroups in the US; however, trend analyses typically examine prevalence of use across years. We sought to determine whether there is seasonal variation in use. Methods We conducted a secondary analysis of the National Survey on Drug Use and Health, a repeated cross-sectional survey of nationally representative probability samples of noninstitutionalized populations age ≥12 in the US. Quarterly trends in any past-month cannabis use were estimated using data from 2015–2019 (N = 282,768). Results Prevalence of past-month cannabis use increased significantly from 2015 to 2019 from...