  Hot Jupiters have been predicted to have a strong day/night temperature
contrast and a hot spot shifted eastward of the substellar point. This was
confirmed by numerous phase curve observations probing the longitudinal
brightness variation of the atmosphere. Global circulation models, however,
systematically underestimate the phase curve amplitude and overestimate the
shift of its maximum. We use a global circulation model including non-grey
radiative transfer and realistic gas and cloud opacities to systematically
investigate how the atmospheric circulation of hot Jupiters varies with
equilibrium temperature from 1000 to 2200K. We show that the heat transport is
very efficient for cloudless planets cooler than 1600K and becomes less
efficient at higher temperatures. When nightside clouds are present, the
day-to-night heat transport becomes extremely inefficient, leading to a good
match to the observed low nightside temperatures. The constancy of this low
temperature is, however, due to the strong dependence of the radiative
timescale with temperature. We further show that nightside clouds increase the
phase curve amplitude and decreases the phase curve offset at the same time.
This change is very sensitive to the cloud chemical composition and particle
size, meaning that the diversity in observed phase curves can be explained by a
diversity of nightside cloud properties. Finally, we show that phase curve
parameters do not necessarily track the day/night contrast nor the shift of the
hot spot on isobars, and propose solutions to to recover the true hot-spot
shift and day/night contrast.
