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The astronomical start of Spring, the Vernal Equinox, March 20 at 4:01 am:
Spring officially begins at 4:01 a.m. Central Daylight Time this Thursday. Why such a specific time, you may ask? Because that’s the exact moment the sun’s direct rays align with the equator.
Houston’s Spring Forecast:
If you’re hoping for a seasonable spring in Houston, you might be out of luck.
According to NOAA, temperatures over the next three months are expected to be above average. Just how much warmer? That largely depends on how much rain we get.
So far this year, Houston has fared well, ending winter with above-average rainfall, and most of Southeast Texas is not in a drought. But with recent cold fronts bringing little to no rain, those rainfall deficits could start creeping up.
Spring trends in Houston:
According to Climate Central, spring in Houston has warmed by 4.1°F since 1970. We now see 24 more above-average temperature days each year compared to back then. A warmer spring isn’t just about the heat, it also means a longer allergy season and an increased wildfire risk. And right now, Texas is feeling the effects firsthand!
- Climate Central analyzed 55 years of temperature data and found that meteorological spring (March-May) has warmed across the U.S. from 1970 to 2024.
- The spring season has warmed in 234 (97%) of the 241 U.S. cities analyzed — by 2.4°F on average.
- Unusually warm spring days now happen more often. Four out of every five cities now experience at least one more week of warmer-than-normal spring days than in the 1970s.
- Spring has warmed the most across the southern tier of the country, particularly in the Southwest.
- Spring warming can prolong seasonal allergies, worsen wildfire risk, and limit snow-fed water supplies.
Why we have seasons:
Did you know Earth doesn’t orbit the sun standing straight up? It’s tilted at 23.5°, and it’s because of that we have seasons. Without it, our weather would stay the same year-round.
At the start of spring and fall, the sun’s direct rays shine right over the equator. Fast forward to this summer, on June 20, 2025, the sun’s rays will reach their northernmost point over the Tropic of Cancer.
But here’s where it gets tricky: the exact time the seasons begin is always different. Why? Because Earth’s orbit isn’t a perfect circle; it’s elliptical. That means our planet’s journey around the sun doesn’t sync perfectly with the calendar. For example, winter usually begins on December 21 or 22, but every so often, it can arrive as early as the 20th or as late as the 23rd.
There are some really cool things about the Vernal Equinox:
- It’s the beginning of spring in the northern hemisphere and the beginning of autumn in the southern hemisphere.
- Day and night are roughly equal but not completely. The reason is that sunrise is defined as the moment the sun’s top edge appears over the horizon, and sunset is when the top edge disappears. Because the sun is a disc, not a point, we see sunlight for a few extra minutes before the actual center of the sun crosses the horizon.
- The day and night that is closest to being equal is called the March Equilux: Saturday, March 15, the sun is above the horizon for 11 hours 59 min 12 sec in Houston.
- Sun rises due east and sets due west.
- Sunrise and sunset are the fastest on the vernal equinox.
