Cloud radiative effects (CRE) have well documented impacts on mean climate, and have recently been found to play a key role in climate variability in the tropics. Here we probe the role of CRE in surface temperature variability in the Northern Hemisphere (NH). We compare output from two climate simulations: one in which clouds are coupled to the atmospheric circulation and another in which they are decoupled from the flow. Cloud-circulation coupling leads to widespread increases in NH surface temperature variability, particularly over the oceans and on decadal timescales. Notably, it leads to substantial increases in decadal temperature variability averaged over the North Atlantic and North Pacific basins. The increases derive from the ‘reddening’ of surface temperature variability by cloud shortwave radiative effects. The results have implications for the interpretation of observed decadal variability, and the importance of cloud-circulation coupling for simulations of decadal variability in climate models.