Atmospheric dynamics is described by a set of partial differential equation yielding an infinite dimensional phase space. However, the actual trajectories followed by the system appear to be constrained to a finite dimensional phase space, i.e. a strange attractor. The dynamical properties of this attractor are difficult to determine due to the complex nature of atmospheric motions. A first step to simplify the problem is to focus on observables which affect – or are linked to phenomena which affect – human welfare and activities, such as sea level pressure, near-surface temperature and precipitation. We make use of recent advances in dynamical systems theory to estimate two instantaneous dynamical properties of the above fields for the Northern Hemisphere: local dimension and persistence. We then use these metrics to characterise the seasonality of the different fields and their interplay. We further analyse the large-scale anomaly patterns corresponding to phase-space extremes – namely timesteps at which the fields display extremes in their instantaneous dynamical properties. The analysis is based on the NCEP/NCAR reanalysis data, over the period 1948–2013. The results show that: (i) despite the high dimensionality of atmospheric dynamics, the Northern Hemisphere sea level pressure and temperature fields can on average be described by roughly twenty degrees of freedom; (ii) the precipitation field has a higher dimensionality; (iii) the seasonal forcing modulates the variability of the dynamical indicators and affects the occurrence of phase-space extremes. We further identify a number of robust correlations between the dynamical properties of the different variables.