Hi, I'm Lisa the Director of Learning at the Space Centre.
With the return of the rain in what some call “Junuary” it doesn’t seem much like we are coming up to the first official day of summer (in the northern hemisphere). But this week we celebrate the summer solstice and the first official day of summer (yeah!).
The summer solstice, the longest day of the year, occurs around June 21 (between June 20 and 22 in the northern hemisphere). In Vancouver in 2020, the solstice happens on June 20 at 2:43 pm. As we get closer to the summer solstice you might notice that the days are getting longer, and the temperatures are getting warmer. On June 20 we will have 16 hours and 14 minutes of daylight (sunrise at 5:06 am and sunset at 9:21 pm). The day might feel even longer because of twilight, the time where the Sun is below Earth’s horizon, but its light is still visible. (If you are curious about twilight and the different kinds of twilight have a look at this web page.
So why do we have warmer weather and longer days in the summer? It is a common misconception that it is warmer in the summer because Earth is closer to the Sun, but this isn’t the case. The reason for our seasons is because Earth is ‘tilted’. Imagine the north pole sticking out of the top of our planet – it doesn’t stick straight up, but on an angle – a 23.4 degree angle. In our summer, Earth’s axis is tilted towards the Sun and the Sun’s rays hit our part of Earth more directly, so it is warmer, and our days are longer. Just how long do summer days get in the summer? Have a look at these locations and compare the length of day for the summer solstice, June 20:
June 20, 2020 – Summer Solstice
| Location | Sunrise | Sunset | Length of day |
| Quito, Ecuador 0° N latitude | 6:12 am | 6:19 pm | 12 hours, 7 minutes |
| Vancouver, BC 49° N latitude | 5:06 am | 9:21 pm | 16 hours, 14 minutes |
| Prince George, BC 54° N | 4:38 am | 9:46 pm | 17 hours, 7 minutes |
| Tuktoyaktuk, NWT 69° N | Visible all day | Visible all day | 24 hours |
Earth isn’t the only planet in our solar system with a tilted axis. Have a look at this image of the planets. How do you think the tilt might affect the length of each planet’s seasons?
Image credit: NASA
As we pass the summer solstice unfortunately our days will start to get shorter but hopefully they will be warmer. We’ve organised this week’s playlists to help you understand the often-misunderstood reasons for the seasons.
| Time | Activity |
|---|---|
| 10mins. | Read this article about why Earth has seasons. |
| 10mins. | Watch this short video about Earth’s seasons. |
| 20mins. | Do this simple experiment to demonstrate how the angle of the Sun’s light affects the temperature on Earth. |
| 30mins. | How might Earth look different from space in different seasons? Explore the images taken from satellites orbiting Earth. Find examples of the four different seasons. |
10mins.
| The tilt of Earth is what causes seasons. Watch this short video about Uranus’ tilt. Do some research to find out about seasons on other planets. |
| Time | Activity |
|---|---|
| 10mins. | Watch this short video about Earth’s seasons. |
| 30mins. | How might Earth look different from space in different seasons? Explore the images taken from satellites orbiting Earth. Find examples of the four different seasons. |
| 30mins. | It is often said that the north has 24 hours of daylight in the summer and 24 hours of darkness in the winter. Do a little investigation to find out how long in the summer and winter this is true. Use the sunlight calculator on timeanddate.com and find places in the world that have 24 hours of sunlight. |
| 30mins. | There are 4 times each year (spring and fall equinox, and summer and winter solstice) where you can figure out your latitude with little more than a protractor, a watch, some wood and very little math (just like the early explorers did). Read this article and give it a try. Ask yourself: What would you need to do at other times of year to measure your latitude? |
30mins.
| Read this article on how a planet’s tilt and its distance from the Sun affects seasons on other planets. |