Purpose To assess the relationship between fractures of the upper limb and the time dimension. Materials and methods A study was conducted of 16,736 patients admitted to Castile-Leon hospitals with a fracture of their upper limb between 1999 and 2004. The following analyses were performed to investigate the existence of rhythm: an univariate analysis performed together with a logistic regression, a rhythmometric study with spectral analysis (Fourier transform) and cosinor method. Results Patients’ mean age was 45.1 ± 25.7 years, with 57.9% of males. The fracture was sustained in an urban milieu in 62.8% of cases and as a result of a road accident in 21.7%. Surgery was performed in 63.1% of cases, with a mortality rate of 1.6%. Mean hospitalization time was 7.21 days. Logistic regression showed a lower risk for older females, in the urban setting. Spectral analysis: dominant period of 365 days. Cosinor analysis: significant rhythm (acrophase: 13/8 and batiphase: 31/12). All subgroups except for deceased patients and those over 84 years showed rhythm (acrophases: 19/7 to 8/9). Conclusions This group of fractures, as well as the majority of subgroups, shows rhythm with acrophases in the summer. Traffic and non-traffic have similar rhythms. The data from the chronobiological study can be applied to clinical practice by planning resources with time-based criteria.