I’ve kept a part of the overwintering chrysalises in the fridge this year. The other part spent winter in the shadow on our balcony. Unfortunately, today I had to realize that some of the butterflies developed too fast in the fridge. Despite of the stable temperature around 5-7 °C the one and only Green Hairstreak (Callophrys rubi) I had hatched. Way too early. The current outside temperature is around the freezing point, and the forecast does not show any spring weather yet. Also the Orange Tips (Anthocharis cardamines) look like they’re about to hatch.
I’ll move the box with butterfly pupae to the balcony, hoping the butterflies will make it through the coming cold weeks. It’s the only chance. If they hatch too early there won’t be company by other specimen in the wild.
Conclusion: Looks like mainly chrysalises of moths that do well overwintering in the fridge. For eggs of hairstreaks or butterfly chrysalises the risk is high that they will develop too early. Note that the winter in Finland lasts much longer than in other regions.