And as everyone who's ever attended a formal occasion in the Irish autumn is already more than aware of, dressing for those transition months is a little trickier than in high summer or deep winter.
So what is one to wear to a September/October occasion that hits the right style notes and also offers a light, airy feel in the event of some sun shine, and a comfortable amount of coverage for a more murky day?
Pretty print dresses are one of the best options for autumn guests - and a midi length will ensure you're free to frolick about holding a drink in one hand and clutch purse in the other in the case of heavy rain.
Jumpsuits are having a moment too, and together with printed pantsuits can offer a chic alternative to the high street dresses favoured by the majority.
If yours isn't the most formal of nuptials, a cute mini shirt dress could do the trick - dress it up with a pretty pillbox hat and structured back and heels and you're sure to stand out from the stylish crowd in the best way possible.