When to go
Best time
Night, Midnight+
All months of the year are suitable to photograph St Paul's Cathedral from the Roof Terrace at One New Change.
I prefer the summer months because the weather will be nicer, but during winter, you won't have to wait as long for the sun to set and there will be less people.
I would visit on a weekday after 10pm. Around dinner time, the terrace can get quite busy and it only clears up later in the night.
Field tips
There will most likely be bouncers and a queue for the bar and restaurant at night. A good tip I have is to speak directly to the bouncers and let them know you're a tourist (if you're visiting from elsewhere) and they'll let you skip the queue to take your photos.
If you're visiting when the temperatures are lower, don't forget to bring a coat. It can get quite windy up on the Roof Terrace!
Since this is a night shot, you'll need a fast lens to shoot handheld or a tripod if you want to use a long exposure for maximum image quality.
Make sure to keep St Paul's centered in the frame to emulate a sense of symmetry.
I think it looks best to position your model to the right to balance out the railings on the left hand side of the image.
Current weather
Do nearby
One New Change is a great place to eat and shop.
If you're looking for additional photography locations, the alleyway from where you walked to get to the rooftop is a classic location for symmetrical reflections.
I highly recommend going inside St Paul's Cathedral. It has an entrance fee, but it's well worth it to see the interior of the historic structure. You can climb all the way up the dome to a viewing balcony at the top, too!
Millennium Bridge, another one of London's iconic landmarks, is only a few minutes walk south of St Paul's.