This page shows the best observability of Pluto over the next few years. The graph will show the time of culmination (highest altitude) unless this would be during daylight, in which case the height shown is at dusk or dawn. Hover over a point to see the time and date. Pluto is quite hard to calculate, so these data may be a bit off.
Note: the data are for a central UK location. To adjust for your location see advice here.