Sparklers are great to add some fun to your wedding and of course a great photo opportunity!
Sparklers can be quite seasonal anyway but I would recommend the best time of year for capturing sparkler shots are when the evenings are drawing in between late September to April.
Obviously you can do them any time of year and whenever your wedding is, but if you are wanting your photographer to capture these images for you, I would say autumn/winter due to light.
In the summer months your going to need to wait until around 10pm for it to be dark enough, most photographers coverage typically ends around first dance time, so this would mean more hours to add to your coverage.
Another thing to factor in as by 10pm onwards your guests may have enjoyed a few drinks so it may prove a little bit harder to do (and safety!) so I find earlier is always better.
