Use this as a starting map, not a rulebook. Weather and events move; hotel and rail availability move faster.
January–February
London museums and theatre · Glasgow and Manchester food · Edinburgh without Festival crush. See UK in winter.
March–May
Bath, York, Oxford, Cambridge, Brighton · first-time London-plus-one-city trips. UK in spring · 5-day England.
June–July
Long evenings · coast · Highlands if you have time. Book Edinburgh before August. UK in summer.
August
Edinburgh Festival or avoid Scotland's capital · London and Bath busy with holidays · Brighton weekends packed.
September–October
Historic cities shine · rail weeks feel spacious again. UK in autumn · 7-day Britain.
November–December
Christmas markets · lights · short days. Christmas city breaks.