It marks the start of each hemisphere’s winter season. The winter solstice marks the official beginning of astronomical winter (as opposed to meteorological winter, which starts about three weeks prior to the solstice). The winter solstice occurs once a year in each hemisphere: once in the Northern Hemisphere (in December) and once in the Southern Hemisphere (in June). *Due to time zone differences, this solstice will technically occur on the next day in some regions. It only gets brighter from here! Winter Solstice Dates Year Think of it this way: Although the winter solstice means the start of winter, it also means the return of more sunlight. Thankfully, after we reach the winter solstice, the days begin to once again grow longer and longer until we reach the summer solstice-the first day of summer and the longest day of the year. (For the Southern Hemisphere, the winter solstice occurs on June 20 or 21.) The winter solstice is the day with the fewest hours of sunlight in the whole year, making it the “shortest day” of the year. The first day of winter in the Northern Hemisphere is marked by the winter solstice, which occurs on Tuesday, December 21, 2021, at 10:59 A.M. EST.įor the northern half of Earth (the Northern Hemisphere), the winter solstice occurs annually on December 21 or 22. A view of one plot in the artificial rainfall experiment at Boyd Deep Canyon Desert Research Center.Advertisement When Is the First Day of Winter?
How to help plants in drought-stricken statesĪ new UC Riverside study shows it's not how much extra water you give your plants, but when you give it that counts. This is especially true near Palm Springs, where the research team created artificial rainfall to examine the effects on plants over the course of two years. This region has both winter and summer growing seasons, both of which are increasingly impacted by drought and, occasionally, extreme rain events. Normally, some desert wildflowers and grasses begin growing in December, and are dead by June. A second community of plants sprouts in July and flowers in August. These include the wildflowers that make for an extremely popular tourist attraction in “super bloom” years. “If we see an increase or decrease in summer rains, or winter rains, how does that affect the ecosystem?” “We wanted to understand whether one season is more sensitive to climate change than another,” said Marko Spasojevic, UCR plant ecologist and lead study author.
The team observed that in summer, plants grow more when given extra water, in addition to any natural rainfall. However, the same was not true in winter. “Essentially, adding water in summer gets us more bang for our buck,” Spasojevic said. Their findings are described in a paper published in the University of California journal Elementa. Over the course of the study, the team observed 24 plots of land at the Boyd Deep Canyon Desert Research Center, in the Palm Desert area. Some of the plots got whatever rain naturally fell. Others were covered and allowed to receive rain only in one season. A third group of plots received additional collected rainwater. While adding water in summer resulted in higher plant biomass, it generally did not increase the diversity of plants that grew, the researchers noted. Decreasing rainfall, in contrast, had negative effects on plants across both summer and winter, but may lead to some increased growth in the following off-seasons. Implications of the work extend beyond learning when additional water resources might be applied simply to help plants grow. Whole communities of animals depend on these plants.