In fact, this time period around the vernal or spring equinox—and actually peaking at the equinox—is the time of year when the number of daylight hours is growing the fastest.
But, you might be wondering, why is that? And for that matter, why does the number of daylight hours change at all throughout the year?
To answer that, we need to talk about a bit of basic Solar System astronomy. How does Picture Earth and all of its inhabitants happily spinning like a top around its axis once per day. Now picture that happily spinning top slowly traveling around the Sun once per year.
With a bit of thought and perhaps a model made with a flashlight and ball , you should be able to convince yourself that if the axis around which the Earth spins is perfectly lined up with the axis around which it revolves around the Sun, then every location on the planet will always experience 12 hours of day and 12 hours of night—every day, all year long.
Unless you've actually been living in a cave and thus not able to see the comings and goings of day and night , you'll recognize that this doesn't sound like the Solar System we live in at all—from which we can draw the conclusion that these two axes must not actually be aligned.
Which is, in fact, true—we know that the axis about which the Earth spins is tilted about What does that do? In short, a lot. Why do daylight hours change? More specifically, for our purposes here the most important byproduct of Earth's tilted axis is the fact that the number of hours of daylight changes throughout the year—and exactly how it changes depends on the latitude at which you live.
If you think about it or take a look at that flashlight and ball model you played around with earlier , you'll see that the top half of the Earth is tilted towards the Sun for half the year and away from it for the other half. Parts of the planet tilted towards the Sun receive more than 12 hours of sunshine per day, parts pointed away from it receive less.
As the Earth travels around the Sun throughout the year, the degree to which a part of the planet is tilted towards or away from the Sun changes. And with that change comes a change in the number of daylight hours that part of the Earth receives. Parts of the planet tilted tow ards the Sun receive more than 12 hours of sunshine per day.
As a location goes from winter into summer, the rate of change in the number of daylight hours peaks at the spring equinox—which is why the number of daylight hours is increasing at a maximum rate right now in the northern hemisphere. After the spring equinox, the rate at which daylight increases tapers off until halting at the summer solstice. At that point the number of daylight hours gradually begins to decrease, picking up steam until reaching a peak at the autumnal equinox and then gradually decreasing until once again halting at the winter solstice.
To learn more or opt-out, read our Cookie Policy. On Sunday, March 8, at 2 am, daylight saving time begins. Yet as simple as it seems, there is still a lot of confusion. The first thing to know: Yes, it begins in the spring, just as the increase in daylight hours starts to become noticeable. And it will end on November 1, right before the darkest time of the year.
Daylight saving time in the US started as an energy conservation trick during World War I and became a national standard in the s. The idea is that in the summer months, we shift the number of daylight hours we get into the evening. Be sure to point out this common mistake to friends and acquaintances.
As Joseph Stromberg outlined in an excellent Vox article, the actual electricity conservation from the time change is unclear or nonexistent :. Studies that evaluate the energy impact of DST are mixed. It seems to reduce lighting use and thus electricity consumption slightly but may increase heating and AC use , as well as gas consumption. Arizona has a simple way to deal with daylight saving time: Most of the state ignores it.
Fifty years ago, the state legislature opted to keep the clocks in most of the state in standard time all year. One reason: Arizona summers are very hot, and an earlier sunset gives residents more time to enjoy tolerable temperatures before bed, as AZcentral explains. In the November election, Californians voted in favor of a ballot measure that paves the way for this. The measure, which passed with 60 percent of the vote , simply grants the California Legislature the power to vote to change the clocks permanently.
The federal government would have to approve it; that has uncertain prospects too. In , the Florida government approved the delightfully named Sunshine Protection Act , which seeks to permanently leave Florida in daylight saving time. Essentially, it would mean that Florida will be one hour ahead of the rest of the East Coast during the winter months.
Massachusetts has looked into a similar measure, too. The bill is still waiting on approval from Congress before it can go into effect. Florida Sen. Other states that have approved legislation to enact year-long daylight saving time include Washington , Tennessee , Oregon , Nevada , and Alabama.
Some Maryland legislators are interested, too. But none of the changes can go into effect without approval from the federal government. Learn More. If you've been wishing for a little bit more daylight to spend time outdoors in the sun, you're in luck. While the typical coldest time of winter has just come and gone across Texas, the days have actually been getting longer ever since the winter solstice on December Known as the "shortest day of the year," we see only around 10 hours of daylight on the winter solstice.
And, as our sun continues to gradually climb higher and higher in the sky each day, we will add on a whopping 30 more minutes or so by the end of the month, with the total up to more than 10 and a half hours of daylight on January
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