The prospects for a record-breaking early Purple Emperor season have faded, due to indifferent May weather. Moreover, the outlook for the next two weeks isn't hot and dry, though it is better for the Southeast, where the Emperor season invariably begins.
Emperor larvae are currently starting to pupate (a few may have already done so in Sussex, Surrey and Kent), but the pupation and pupal processes this year are likely to be drawn out by relatively low temperatures and spells of rain.
At this range, we are on for a mid-June start in Sussex and Surrey, though an earlier start remains possible.
Some midsummer species are, though, still on for very early flight seasons, having jumped the gun in early spring (notably White-letter Hairstreak but probably also some of the Browns.
Here's my captive PE larva, 'Mr Tumnus' - only it looks like he's successfully transitioned to 'Miss Tumnus'...
Coming soon: Visiting Knepp in '24