It’s the coldest time of the year in the northern hemisphere, and time to think a bit about how that happens and what it means to us. Of course, it mostly means it’s going to be cold!  But it also means things for our biology and for the way the earth turns. Literally.  

As a biologist, I learned that we humans (and almost all other creatures and plants) are synchronized to at least the daily light and dark cycles. This has produced circadian rhythms in you and me, which gives us a great advantage. It keeps us awake and alert during the daytime hours, and asleep during the dark hours. It’s an advantage, of course, because thinking about humans before we had artificial lighting, you’re at a distinct disadvantage wandering around at night. Lots of other creatures can see much better than you can; you can see the things you might run into – trees, rocks, bigger carnivores – or fall off of – cliffs, etc. Being a day-active human definitely has its perks.

Puppy sleeping under blankets

Winter complicates things for night and day – the days get shorter and the nights longer. This is because the earth is a very reliable spinning top, but it’s tilted 23.5 degrees. In the northern hemisphere, the winter tilt away from the sun means we spend less time bathing in the sun’s light, which means we can’t really warm up the land very well. Without that warmer land, the air around us never heats up much and… well, it’s time to break out the extra blankets and some hot chocolate.

The shortest day of the year isn’t when we have the coldest temps – our shortest day is the solstice in December, and the temps hit their average low in January, about a month later. Why? Turns out the heat that’s stored in the ground and water and air takes some time to circulate, and the temperatures “lag” about a month behind the day length. Same thing in summer – the longest day is in June, but the highest average temps are in July. It’s kinda like how you need to wait for the things you put in the oven or the fridge to “get hot” or “get cold.” It takes a while.

Two cool things that also happen around this time of year:

  1. You can use high-intensity lights in the morning and evening to ward off “seasonal affective disorder” which some people get if not enough bright light enters their eyes. This artificially extends your “daytime” in the winter and makes some parts of your brain think it’s closer to summer, and;
  2. The people around the Arctic Circle will see the sun pop above the horizon at noon in early February – and they haven’t seen it since some time in October. If you want to see what this is like, you can go to and use their online planetarium – set the clock to late January / early February and the location to “Utqiagvik (formerly known as Barrow) Alaska.” Play with the time controls to see when residents get their last and first glimpses of the sun. Spending a winter there is on my bucket list, so I can see the return of the sun to the sky. Here in Southern New England, my winter joy awaits next month with the local maple sap starts running. See you then!



As Associate Director / Programming & Instruction, John Pellino oversees Outreach, Saturday, Vacation and Summer programs for TMSC, Computers and Technology for TMSC and TMA, and TalcottOnline. John first attended Talcott as a 6th grader from nearby Simsbury. With a degree in Biology (BA, St. Anselm College, 1980) and graduate coursework in Educational Technology and Educational Psychology. Mr. Pellino joined TMSC full time as a Research Assistant and has, since then, also served as Research Associate, Instructor, Assistant Director and Associate Director. Projects at Talcott have included Project TEMPO (student health education), External Research for Apple Advanced Technology Group, The Jason Project, NSF Urban Network, The GLOBE Program, Coordinator and Coach for FIRST Robotics, FIRST LEGO League, and Trinity College Firefighting Robotics, as well as design and implementation of Connecticut’s first science teacher network.