What Time Does It Get Dark?
As we head into March (with Spring just on the horizon!) it’s common to ask: what time does it get dark? After so many months living with a small window of sunlight, surely we must be coming out of the darkness? In today’s blog, we’ll talk about why it’s darker in the winter, how long it takes to get dark after sunlight, and when we can expect it to get dark in the coming weeks.
Why is it darker in the winter?
As you may remember from science class, our planet is part of a system that travels around the sun. From this star we receive much needed light and heat. However, Earth is on a titled axis meaning that a portion will be titled towards the sun, while a portion will be titled away from it.
Therefore the Earth receives different amounts of sunlight in different seasons. This results in the Northern hemisphere being titled towards more sunlight, and thus longer days, in the summer. And vice versa in the winter. This is also why it’s colder due to less solar radiation from fewer contact hours.
This works similarly (although at opposite times) for those in the Southern Hemisphere. However, those living on the equator (the middle line that wraps around the sphere) experience days and nights that are mostly equal.
How long does it take to get dark after sunset?
You may notice when watching a sunset that it doesn’t go completely dark right away. Again, this has to do with the spherical shape of our planet. Even if the sun has set on our horizon, it still continues to shine on the atmosphere above the Earth’s surface. This has to do with light interacting with various gas molecules which causes it to scatter.
This phase of the night sky is known as twilight. There are three stages of twilight:
- Civil Twilight. This is when it’s still light enough to see.
- Nautical Twilight. This is when objects appear more as silhouettes. Stars and constellations are now visible in the sky.
- Astronomical Twilight. This is what we would call night. It is truly dark which is the perfect time for viewing space objects.
Experts estimate that it takes around 70 – 100 minutes for our environment to go through these three stages. Meaning that it gets truly dark around an hour and a half after sunset.
Important Dates Coming Up in March
There are some important dates coming up in March that will affect how we determine the time of darkness.
Daylight Savings exists to make the most of natural light. Clocks “go back” for the winter months and “go forward” for the summer months. At 2am on March 14th 2021, we “lose an hour of time” signifying our transition into longer days in the Northern Hemisphere. After this date, the time it gets dark will keep getting later and later.
March Equinox is on the 20th of the month and signals the start of Spring. This is when the sun crosses the celestial equator moving from South to North. It is also the date when the length of day and night is pretty much the same across the world.
So, what time does it get dark?
It appears that this question is a little difficult to answer with the up-coming sunlight transitions that happen in March.
- For the first half of the month, expect sunset to be around 5.45pm with total darkness appearing around 7.15-7.30pm.
- After daylight savings, sunset will be around 6.45pm with darkness settling in around an hour and a half later.
- Once March Equinox has marked the start of Spring, sunset will continue to be pushed further and further into the evening. In fact, some Northern countries may not experience true darkness at all come the summer months.