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Arab News
an hour ago
- Science
- Arab News
Solstice ushers in start of summer 2025 on Saturday
RIYADH: The summer solstice, which marks the season's astronomical beginning, will take place on Saturday, June 21, according to the Jeddah Astronomical Society. The Kingdom will witness the solstice at 5.42 a.m. Makkah time, when the sun will be directly overhead above the Tropic of Cancer, latitude . The skies of the Kingdom and the rest of the Northern Hemisphere will witness the summer solstice Saturday at 5:42 am Makkah time. At this moment, the sun will be directly overhead above the Tropic of Cancer, latitude 23.5 degrees north. This year, the summer will last for 93 days. Majed Abu Zahra, head of the Jeddah Astronomical Society, said: 'On this day, the sun rises from the far northeast and sets in the far northwest. At noon, the shadows of objects are the shortest of the year, and the sun's apparent path takes its highest arc northward, placing it at its highest altitude in the sky during the year, especially in areas north of the equator.' The summer solstice occurs when the sun reaches its apparent northernmost point in the sky. This coincides with the Earth reaching a position in its orbit where its axis is tilted at the maximum angle (23.5 degrees) toward the sun, causing the longest day and shortest night of the year in the Northern Hemisphere. In the Southern Hemisphere, the situation is reversed. Abu Zahra added: 'The summer solstice does not occur on the same day every year, but rather between June 20 and 22, due to the difference between the calendar year (365 days) and the tropical year (365.2422 days), along with the gravitational effects of the moon and planets and the slight fluctuations in the Earth's rotation, which are compensated for by adding a leap day every four years.' He said it was important to differentiate between the astronomical summer and climatic summer. Meteorologists consider summer to extend from June 1 to August 31, while in astronomy, summer begins when the sun reaches its maximum altitude — the day of the summer solstice. Abu Zahra said although this was the longest day of the year in terms of the number of hours of sunlight, it was not necessarily the hottest. This is because the oceans, land and atmosphere take time to absorb and store solar energy, and then release it again. This delay in the perception of heat is known as 'seasonal lag,' so temperatures typically peak in July or August. Ancient Greek scholars, led by Eratosthenes, used their observations on the summer solstice to calculate the Earth's circumference with amazing accuracy using simple geometric principles. After the summer solstice, the sun will appear to move southward again in the sky, and daylight hours will gradually decrease until the autumnal equinox on Sept. 22.
Yahoo
3 hours ago
- Yahoo
Summer solstice 2025 brings changing seasons to Earth on June 20
When you buy through links on our articles, Future and its syndication partners may earn a commission. Summer will officially arrive on Friday in what is known as the Summer Solstice. At 10:42 p.m. EDT on June 20 (0242 GMT on June 21), the sun will reach that point where it is farthest north of the celestial equator. To be more precise, when the solstice occurs the sun will appear to be shining directly overhead for a point on the Tropic of Cancer (latitude 23.5 degrees north) in the western Pacific Ocean, roughly 1,400 statute miles (890 km) to the south of Tokyo, Japan. From mid-northern latitudes, we can never see the sun directly overhead, but (as an example) as seen from Philadelphia at 1:02 p.m. EDT on the day of the summer solstice, the sun will attain its highest point in the sky for this entire year, standing 73 degrees above the southern horizon. To gauge how high that is, your clenched fist held at arm's length measures roughly 10 degrees, so from "The City of Brotherly Love," the sun will appear to climb more than "seven fists" above the southern horizon. And since the sun will appear to describe such a high arc across the sky, the duration of daylight will be at its most extreme, lasting exactly 15 hours. But this doesn't mean that we can stargaze for the 9 hours remaining because we also need to take twilight into consideration. Around the time of the June solstice at latitude 40 degrees north, morning and evening twilight each last just over 2 hours, so the sky is fully dark for only 5 hours. Farther north, twilight lasts even longer. At 45 degrees it lingers for 2.5 hours and at 50 degrees twilight persists through the entire night; the sky never gets completely dark. In contrast, heading south, the duration of twilight is shorter. At latitude 30 degrees it lasts 96 minutes while at the latitude of San Juan it only lingers for 80 minutes. Which is why travelers from the northern U.S. who visit the Caribbean at this time of year are so surprised at how quickly it gets dark after sunset compared to back home. Incidentally, the earliest sunrise and latest sunset do not coincide with the summer solstice. The former occurred on June 14, while the latter does not come until June 27. Most people are probably under the impression that the Earth is closest to the sun in its orbit at this time of year, but actually, it is just the opposite. In fact, on July 3, at 19:55 Universal Time or 3:55 p.m. Eastern daylight time, we'll be at that point in our orbit farthest from the sun (called aphelion); a distance of 94,502,939 miles (152,087,738 km). Conversely, it was back on Jan. 4 that Earth was at perihelion, its closest point to the sun. The difference in distance between these two extremes measures 3,096,946 miles (4,984,051 km) or 3.277 percent, which makes a difference in radiant heat received by the Earth of nearly 7 percent. Thus, for the Northern Hemisphere the difference tends to warm our winters and cool our summers. However, in reality, the preponderance of large landmasses in the Northern Hemisphere works the other way and overall tends to make our winters colder and summers hotter than those of the Southern Hemisphere. After the sun arrives at its solstice point, it will begin to migrate back toward the south and the amount of daylight in the Northern Hemisphere will begin to decrease. Consider this: after Friday, the length of daylight will not begin to increase again until three days before Christmas. But actually, if you think about it, the sun has been taking a high arc across the sky and the length of daylight has been rather substantial since about the middle of May. And the lowering of the sun's path in the sky and the diminishing of the daylight hours in the coming days and weeks will, at least initially, be rather subtle. Aug. 1 is marked on some Christian calendars as Lammas Day, whose name is derived from the Old English "loaf-mass," because it was once observed as a harvest festival and was traditionally considered to be the middle of the summer season. In actuality, however, summer's midpoint — that moment that comes exactly between the summer solstice and the autumnal equinox in 2024 — will not occur until Aug. 6 at 6:30 p.m. EDT. On that day, again, as seen from Philly, the sun will set at 8:08 p.m. with the loss of daylight since June 20 amounting to just 56 minutes. But it is in the second half of summer that the effects of the southward shift of the sun's direct rays start becoming much more noticeable. In fact, when autumn officially arrives on Sept. 22, the sun for Philadelphians will be setting a few minutes before seven in the evening (6:57 p.m.), while the length of daylight will have been reduced by nearly two hours (1 hour 55 minutes to be precise) since Aug. 6. RELATED STORIES: — The summer solstice: What is it and when does it occur? — Midnight sun: What it is and how to see it — 365 days of satellite images show Earth's seasons changing from space (video) When he occasionally played left field during his Hall of Fame career with the Yankees, Yogi Berra would say that he didn't mind the outfield, except that during August and September, as the shadows across the ballfield progressively lengthened, it made it increasingly difficult for him to see a baseball hit in his direction. Yogi might not have been able to explain the science of why the altitude of the sun lowered so perceptibly during the latter half of the summer, but — as only Yogi could do — he was able to sum it all up in a simple Yogism: "It's getting late early out there." Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for Natural History magazine, Sky and Telescope and other publications.
Forbes
5 hours ago
- Science
- Forbes
Summer Solstice 2025: The Exact Time For Every U.S. State
The 2025 solstice — the longest day of the year in the Northern Hemisphere and the shortest in the Southern Hemisphere — will occur at 02:42 UTC on Saturday, June 21. However, in North America, it happens the previous day. People watch the sun rise, as they take part in the Summer Solstice at Stonehenge in Wiltshire, ... More Friday, June 21, 2024. (Andrew Matthews/PA Wire/PA via AP) June's solstice marks the longest day of the year and the beginning of astronomical summer in the Northern Hemisphere. It's not only the longest day but also the point when daylight begins to shorten. The solstice occurs at a specific global time (02:42 UTC on June 21), so its local time varies across U.S. time zones. The 2025 summer solstice occurs at 10:42 p.m. EDT, 9:42 p.m. CDT, 8:42 p.m. MDT, 7:42 p.m. PDT, 6:42 p.m. AKDT and 4:42 p.m. HST on Friday, June 20. At that precise moment, the sun will be directly overhead at the Tropic of Cancer at noon somewhere on Earth. It's the northernmost point of the sun at noon. Solstice is from the Latin solstitium, sol meaning sun and stit being stationary. That's because, as a consequence of the sun reaching its highest in the sky in the Northern Hemisphere, its rise and set points are at their extreme northeast and northwest, respectively. To the observer, the sun appears to rise farther northeast until June's solstice, when it appears to stand still for a few mornings before rising farther east and south. Although Stonehenge is traditionally associated with the solstice (it's aligned with the rising sun on the solstice), there are other ancient monuments with a solstice link. Egypt's Nabta Playa stone circle, the oldest known astronomical site, tracks the solstice, with no shadows cast by its stones at noon on the date of the solstice. According to Astronomy magazine, Nabta Playa was constructed by a cattle-worshiping cult of nomadic people to mark the summer solstice and the arrival of the monsoons. At 7,000 years old, it's older than Stonehenge. The 2025 solstice will occur at 02:42 UTC on Saturday, June 21, 2025. The Tropic of Cancer is a line 23.4 degrees north of the Earth's equator through The Bahamas, Mexico, Egypt, Libya, Niger, Algeria, Mauritania, Mali, Chad, Saudi Arabia, United Arab Emirates, Oman, India, Myanmar, China and Taiwan. It reflects the tilt of the Earth's axis, which explains why the planet has solstices, equinoxes and seasons. The beginning of astronomical seasons is marked by solstices and equinoxes (equinox means equal night when there are 12 hours of daylight and 12 hours of darkness). The spring or vernal equinox occurs between March 19-21, the June solstice June 20 and 22, the September equinox September 21-24 and the December solstice is December 20-23, according to In 2025, they occur on March 20, June 20, Sept. 22 and Dec. 21, respectively.
Washington Post
14 hours ago
- Climate
- Washington Post
What to know about the summer solstice, the longest, brightest day of the year
Summer officially begins Friday, June 20, at 10:41 p.m. Eastern time. That's the precise moment of the summer solstice — making for the longest, brightest day of the year in the Northern Hemisphere. Temperatures are toasty and the humidity is sweltering across much of the Lower 48. There's no denying it's summer. On Friday, Washington, D.C., will enjoy 14 hours and 54 minutes of daylight. Dallas will get 14 hours and 19 minutes, and Seattle will get just shy of 16 hours. Remember — the days will be longest farther north, with the fewest daylight hours in the Southern Hemisphere. There's more annual variation in day length toward the poles, and the most consistency at the equator. The summer solstice has to do with Earth's tilt on its axis. Because of our 23.5-degree tilt, the amount — and intensity — of sunlight any given area receives varies throughout the year. For half the year, the sun's most direct rays shine on the Northern Hemisphere; the other half of the year, the Southern Hemisphere. Since our tilt is 23.5 degrees, that means the sun's direct rays fall between 23.5 degrees north and 23.5 degrees south latitude at all times throughout the year. Those lines represent the Tropics of Cancer and Capricorn. (Technically, the actual latitudes are 23.4394 degrees north and south.) On the June solstice, the sun shines directly on the Tropic of Cancer in the Northern Hemisphere. That means that, poleward of that line, everyone in the Northern Hemisphere is experiencing their longest, brightest day. And if you stand on that line, you'll have no shadow at noon — the sun will be directly over you. After Friday, the sun's most direct rays begin retreating southward again. On the autumnal (fall) equinox, or Monday, Sept. 22, those most intense rays will cross into the Southern Hemisphere. Our days will get shorter and darker until the winter solstice on Dec. 21. Even as the days get shorter, that doesn't mean it will start getting cooler. There's something called seasonal lag that prevents that from happening. The atmosphere has a certain amount of thermal inertia, or resistance to changing temperature. Light hits the ground and is converted to heat, which is dispersed through the atmosphere. The diffusion of that heat takes a while. The lag — or time between greatest amount of sunlight and warmest temperatures — is about a month. That's why July tends to be the hottest month for North America, Europe and Asia. Technically speaking, every place on Earth gets about the same duration of sunlight every year. It would be exactly the same if we were a perfect sphere, but between mountains and Earth's equator, which bulges outward 27 miles, it's a bit imperfect. What varies is the intensity of the daylight. Take the north pole, for example. Even on the summer solstice, the sun is very low in the sky. The sunlight comes at a steep angle and is weak — which is why it's so cold at the poles. Day length changes the most at the poles and changes the least at the equator. At the equator, every day is a little more than 12 hours long. In the Arctic and Antarctic circles, there's at least one day per year with 24 hours of sunlight, and another with 24 hours of darkness. At the mid-latitudes, people experience a couple of hours of variation, but it's not that extreme. In D.C., for instance, the summer solstice has 14 hours and 53 minutes of sunshine. The winter solstice has just 9 hours and 26 minutes.
BBC News
21 hours ago
- Science
- BBC News
Summer solstice 2025: When is it and what does it mean?
For some it marks a celebration at dawn. For others, it is the start of summer and the promise of warmer days to summer solstice is the longest day of the year, meaning the day with the most hours of year, the summer solstice in the Northern Hemisphere falls on Saturday, 21 with parts of the UK already experiencing their first heatwave of the year it's likely to be a warm one. Why does the date change? The solstice always occurs between June 20 and 22, and during a leap year, it typically falls on June exact date shifts slightly each year because the calendar year doesn't perfectly match the time it takes for the Earth to orbit the fact, the Earth takes nearly a quarter of a day longer to complete its orbit each year than our calendar accounts discrepancy is why we add a leap day every four years—to keep the calendar aligned with Earth's orbit Why does the amount of sunlight vary? Our planet does not spin on a perfectly vertical axis — it is tilt causes the amount of sunlight that reaches different regions of Earth to change throughout the year as it orbits the half the year, the northern half of the Earth is tilted toward the Sun. On the summer solstice, the Northern Hemisphere is tilted most directly toward the Sun, and the Sun appears directly overhead at the Tropic of this tilt, we would still experience weather, but not distinct seasons, as the amount of daylight would remain nearly constant throughout the word solstice comes from the Latin words sol (sun) and sistere (to stand still), referring to the apparent pause in the Sun's movement across the sky. How much daylight will there be? Due to the tilt of the Earth, the period of daylight will be longer at higher this time, Norway, Finland, Greenland, Alaska and other polar regions experience 'midnight sun'. And across the Arctic Circle, down to a latitude of 23.5 degrees from the North Pole (matching the tilt of the Earth), the Sun does not set at it may be the longest day but it is not the latest sunset or the earliest sunrise. The earliest sunrises happen before the summer solstice, and the latest sunsets happen after. Check sunrise and sunset times where you are on the BBC Weather app and website. Is this the start of summer? Meteorologically, we are nearly a month into summer. Astronomically, however, the solstice marks the beginning of most people refer to the first day of summer, they mean astronomical summer—the summer contrast, meteorologists define summer in the Northern Hemisphere as beginning on June 1 and ending on August seasons are divided into four three-month periods, which makes it easier to compare seasonal statistics. Will this be the warmest summer solstice on record? Some parts of the UK are already experiencing their first heatwave of the year and forecasters expect temperatures to peak at around 33C on it is unlikely to be the highest temperature experienced on the day of the summer solstice. That record was set in 2017 at Heathrow Airport when 34.5C was while the summer solstice is the day with the most sunlight, the UK's weather becomes hotter later in the summer, when more heat has accumulated in the air and the ground.
