That apparently depends on the butterflies. There has been some dialogue on Twitter that has revolved around an old belief that if the first butterfly seen in a year is yellow, then it will be a good summer, if it is white it will be a quiet summer and if it is brown or orange it will be a terrible summer.
I am not sure where this piece of wisdom has come from. There are four butterflies that overwinter as adults; Brimstones, Commas, Small Tortoiseshells and Peacocks. Therefore if you should see Brimstones first then the summer will be good, see one of the others and we are doomed to a watery summer, see a white butterfly and, I can only assume they mean an Orange Tip as they are the first white-coloured butterflies that are about, then it will be quiet.
I wondered if the reason for this was that Brimstones tend to overwinter outside and therefore if they are in a place that catches the sun then the air will warm up around them (they often shelter under dark coloured ivy) and they might be tempted outside if it is a particularly warm sunny day. However, the Small Tort and Peacocks tend to overwinter in old buildings and sheds and are therefore less likely to experience sudden changes in temperatures and probably wouldn’t notice an occasional sunny day. However, this doesn’t take into account the fact that Commas also spend the winter in the undergrowth so they should be out with the Brimstones. Maybe Commas need the weather to be a bit warmer, or maybe they are much less noticeable than a bright yellow butterfly catching the sun as it flits past so they tend to be overlooked. If the Orange Tips are out first then it must be April and hasn’t been particularly warm or cold so far and possibly a bit damp as they tend to spend the winter as pupae and then emerge to patrol damp verges and ditches to look for a mate.
Unfortunately I haven’t been keeping track of which butterfly I have been noticing first for the last few years – in Northamptonshire the Peacock has beaten the Brimstone for the last couple of years, but I wonder if that is because some have been overwintering in heated buildings and have come out in January. For those that are interested my first butterfly this year was a Brimstone seen on 7th March, with Peacocks and Small Torts turning up a couple of days later along with a lot more Brimstones. So, maybe it will be a Butterfly Summer after all (fingers crossed).