We are independent & ad-supported. We may earn a commission for purchases made through our links.

Advertiser Disclosure

Our website is an independent, advertising-supported platform. We provide our content free of charge to our readers, and to keep it that way, we rely on revenue generated through advertisements and affiliate partnerships. This means that when you click on certain links on our site and make a purchase, we may earn a commission. Learn more.

How We Make Money

We sustain our operations through affiliate commissions and advertising. If you click on an affiliate link and make a purchase, we may receive a commission from the merchant at no additional cost to you. We also display advertisements on our website, which help generate revenue to support our work and keep our content free for readers. Our editorial team operates independently from our advertising and affiliate partnerships to ensure that our content remains unbiased and focused on providing you with the best information and recommendations based on thorough research and honest evaluations. To remain transparent, we’ve provided a list of our current affiliate partners here.

What is Nautical Twilight?

Mary McMahon
By
Updated May 21, 2024
Our promise to you
All The Science is dedicated to creating trustworthy, high-quality content that always prioritizes transparency, integrity, and inclusivity above all else. Our ensure that our content creation and review process includes rigorous fact-checking, evidence-based, and continual updates to ensure accuracy and reliability.

Our Promise to you

Founded in 2002, our company has been a trusted resource for readers seeking informative and engaging content. Our dedication to quality remains unwavering—and will never change. We follow a strict editorial policy, ensuring that our content is authored by highly qualified professionals and edited by subject matter experts. This guarantees that everything we publish is objective, accurate, and trustworthy.

Over the years, we've refined our approach to cover a wide range of topics, providing readers with reliable and practical advice to enhance their knowledge and skills. That's why millions of readers turn to us each year. Join us in celebrating the joy of learning, guided by standards you can trust.

Editorial Standards

At All The Science, we are committed to creating content that you can trust. Our editorial process is designed to ensure that every piece of content we publish is accurate, reliable, and informative.

Our team of experienced writers and editors follows a strict set of guidelines to ensure the highest quality content. We conduct thorough research, fact-check all information, and rely on credible sources to back up our claims. Our content is reviewed by subject matter experts to ensure accuracy and clarity.

We believe in transparency and maintain editorial independence from our advertisers. Our team does not receive direct compensation from advertisers, allowing us to create unbiased content that prioritizes your interests.

Nautical twilight is a period in the morning and evening when the sun is between six and 12 degrees below the horizon. Some visible light is present, but not enough to conduct detailed activities without the use of artificial light, and the horizon tends to be somewhat indistinct during this period. People refer to this time of day as “nautical twilight” to reference the fact that sailors often took navigational observations during this time, since the visibility was ideal.

While many people think of twilight as a time roughly between when it is not totally dark and when it is clearly light outside, this period of the day is actually broken into several distinct categories. Civil twilight occurs when the sun is less than six degrees below the horizon, allowing people to see things clearly, although the sun is obviously on the way up or down. Next comes nautical twilight, followed by astronomical twilight between 12 and 18 degrees, and when the sun is more than 18 degrees below the horizon, it is considered night.

In the morning, people may refer to nautical twilight as “first light,” the period when light first begins to be visible and the sky slowly starts to flush with color as the sun comes up. Haze and other obstructions to visibility tend to be low during this period, although cloud cover and fog can interfere with the perception of first light. People usually need headlights to drive and artificial light to work outdoors during nautical twilight.

At night, nautical twilight is sometimes called “nightfall,” referencing the fact that the sky is rapidly starting to darken, and it is soon going to be so dark that artificial light will be a necessity. Visibility can be tricky during this time, as people may think that it is lighter than it really is, and they may therefore refrain from using headlights and other aids to visibility, which can result in accidents.

The length of time spent in twilight varies, depending on where in the world one is, and what time of year it is. Twilight tends to be the longest in the poles, and the shortest around the equator; in Alaska, for example, twilight can last several hours during some periods of the year, while in parts of Africa, light levels go from full daylight to night in 20 minutes. Specific information about twilight times and length is usually provided in sunrise-sunset charts issued by organizations which provide weather information.

All The Science is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.
Mary McMahon
By Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a All The Science researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

Discussion Comments

By highlighter — On Nov 02, 2010

@ PelesTears- There actually is a movie shot in a town in Alaska where the sun sets, leaving twilight to blanket the town for a month. The movie is called 30 days of night, and it is actually a good movie as far as vampires are concerned. These are not the types of vampires that sparkle in the sunlight...oh no, these are the superhuman creatures that kill at will to suck blood. Basically, a group of vampires enters this town as twilight falls over the residents and go on a month long killing spree. If you are into horror movies, you should check this one out.

By PelesTears — On Nov 02, 2010

I have heard that places in Alaska and the Arctic region are in perpetual twilight for certain times of the year. I have also heard that these same places have months of perpetual daylight on opposite times of year. This would be such an amazing experience. I would like to take a trip to one of these towns and stay for a week during the month of darkness. You would think that this would make a great setting for a vampire movie since the creatures supposedly dislike sunlight.

By Alchemy — On Nov 02, 2010

What an interesting article. I have never thought about the length of twilight, but now that I have read this article, I have noticed the difference. I used to live in Vermont, and there was a place I would go to watch the sunset. It was a tall point that you had to hike about a quarter mile too, but once you were there, you could see the entire river valley about 500 feet below. It was the perfect location for watching the sunrise. A group of friends and I would come here after a long night of partying, or in the mornings while we were on camping trips in the area. The sunrises at this area would last about an hour and the change from dark to light was very gradual.

I now live in Phoenix, and I occasionally drive to South Mountain for sunrise. The sunrises are noticeably shorter, but equally as serene. I often see coyotes and roadrunners making their way out of their den to forage for the day.

Mary McMahon

Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a...

Learn more
All The Science, in your inbox

Our latest articles, guides, and more, delivered daily.

All The Science, in your inbox

Our latest articles, guides, and more, delivered daily.