Abigail James, UK
Whilst in no way an expert I have noticed within the past 5 years a change in our seasons from being fairly well defined to being out of synch with my memory as a child growing up.
Now we have very hot days in February & March where we can sit outside in our garden for lunch to needing to water heavily (and needing to buy more water butts to collect the little rain we have in the Spring) in April and May this year; not necessarily because it was hot and sunny, but because there was no rainfall of any consequence for weeks.
I also notice flowers coming up early and have a rhododendron in a second flowering as I write this. I don't know if this is unusual, but it's never happened before. Last 'winter' I had snowdrops starting to show in December along with the odd daffodil.