Exterior lighting is pretty spectacular. It allows us to get out and about safely after dark and brings highstreets and town centres to life once the sun sets.

But too much of it (or the right amount in the wrong places) and it’ll disturb the natural environment and cause light pollution, which has contributed to a 9.6% rise in sky brightness between 2011 and 2022 — bad news for anyone that cares about protecting the world around us and its inhabitants.

Thankfully, there are plenty of initiatives encouraging people to do their bit to stop this from worsening — and one of them is International Dark Sky Week, which is taking place from 15 to 22 April 2023!

This seven-day event is dedicated to safeguarding the night sky (a cause worth supporting, in our humble opinion). Anyone is welcome (and encouraged) to join in, so we’re here to tell you all about it — and how councils and authorities can use its principles long after the event ends…


International Dark Sky Week began 20 years ago with a student named Jennifer Barlow. Hoping to ensure the moon and stars can continue providing scientists, philosophers, artists and writers with inspiration, she set out to create a movement that prevented light pollution from interfering with anyone’s ability to see the night sky.

Two decades later, International Dark Sky Week is a global phenomenon where people unite every year to raise awareness of the dangers of the excessive and improper use of exterior lighting. The event focuses on animal welfare and human health and well-being, and it’s not hard to see why…

By messing with ambient light levels that usually change with the seasons, exterior lighting can disrupt animals’ biological clocks. For birds, this can mean relocating at the wrong time or veering off course, resulting in them missing ideal climate conditions, as well as opportunities to mate and forage. Birds can also collide with brightly lit objects, causing fatal crashes and population declines that wreck food chains.

Excessive blue light levels from poor exterior lighting schemes can also negatively impact our own body clocks, keeping us awake at night. Without proper sleep, the likelihood of suffering from illnesses such as depression, diabetes and obesity rises.

Essentially, dark skies are not only nice to look at — we need them to survive.

Whilst homeowners participating in International Dark Sky Week might make small changes to help, like turning porch lights off when they’re not needed, individual efforts won’t cut it if we’re to save the night sky from light pollution.

Instead, we need entire communities to make the change to sky-friendly lighting — and we’re looking at you, councils and authorities, to take things one step further by upgrading exterior lighting schemes in our towns and cities. 


There’s an endless list of ways councils and authorities can limit light pollution in exterior lighting schemes on a large scale.

Sometimes, it’s simply a case of improving pre-existing schemes. For example, retrofitting old streetlights with LEDs can help reduce light spill and minimise light pollution, as they’re much more precise than traditional bulbs. Plus, you can combine them with adaptive lighting profiles to lower lumen levels and use warm white colour temperature streetlights for minimal disruption.

But if you really want to keep dark skies dark, it’s worth taking a long, hard look at your lighting design and considering whether you should start from scratch. Or being really bold, asking yourself if you need to provide any lighting for the area in the first place!

For instance, if there are more lights than are necessary around public spaces and facilities, you can limit light pollution by making sure they are located where they’re needed most — like near hazards, parking spaces and entrances and exits. Ensure they’re all pointed downwards, do not project light upwards or outwards unnecessarily and you’ll help keep the night sky deep and dark and light the area with fewer lights too.

Although working on a new exterior lighting scheme might be the last thing on your mind with sunny mornings and lighter evenings on the horizon, we’re saying this now for a reason.

Not only will these changes help you save a few bob amidst the current economic situation, but if you put in the hard work this spring, you’ll have an ace lighting scheme ready and waiting for when the longer nights return — AKA when it’s needed most!

You know what they say: the best winter lighting schemes are designed in the summer (or something like that).  But shouldn’t be rushed through without considering our dark skies…all year! 

For help designing a sky-friendly exterior limiting scheme, email us at info@dfl-uk.com or call +44 (0)1962 855080. Our lighting impact assessments are a great place to start…