Good news – summer is on its way! At 10:47 Monday morning we passed through the winter solstice. The dreaded shortest day of the year. It's all clear sailing from here to summer when we can shuck the parka, and stow the snow shovel. In the meantime, we have a bit of darkness to get through.

Perhaps more than anything else, the current festive season is about light, or the lack of it. That Judaism, Christianity and others mark major celebrations at this time of year is not coincidental. As largely northern hemispheric cultures, the lack of light around the winter solstice has played an important role in the annual cycle of life.

Was Jesus really born on December 25? The exact date of his birth is much debated, with many believing it to be unknown. The holiday celebrating his birth is rich with the symbols of light, from Christmas trees to Bethlehem's star and makes Isaiah's prophetic metaphor most fitting: "The people who have walked in darkness have seen a great light". Bringing light into the world at the time of the greatest darkness only makes sense.

Jewish people mark the eight days of Hanukkah (the festival of lights) at roughly the same time. Successive candles are lit daily on the menorah marking the length of a miraculous lamp's persistance almost 2400 years ago, as the Jewish people reclaimed Jerusalem's temple from foreign occupation. Hindu's festival of light, Diwali, falls a bit earlier, on the new moon of the Hindu month of Kartik (October/November) but is still based on a similar premise: lighting up the darkness.

Virtually every northern culture has marked the solstice and celebrated the coming return of the sun. On the Scottish Orkney Islands, ancient Celts built the Maes Howe, a burial crypt that looks much like a stone igloo. The central room is dimly lit by indirect light seeping through the waist-high entrance way. But at sunset on the winter solstice, for a few minutes on that one day a year, the sun shines directly down the entrance and floods the crypt with light. Clearly, this day was an important one for these people.

Light is a powerful symbol because without it life as we know it on earth would cease. Virtually all life is based on converting the sun's energy into forms that allows organisms to grow and reproduce. We can bend it, refract it, reflect it and split it into various wavelengths that give us colour. We capture it in solar cells and transform its power into electricity. In a world of uncertainties, light offers us a reassuring constant (299,792,458 metres per second to be exact).

The other holiday we are celebrating is the New Year, marked by the western calendar each January. But why now? The beginning of a new school year each September would seem to be a fitting time to start a calendar. It would certainly simplify many aspects of life. At least in the northern hemisphere. Spring is also a season ripe with symbols of regeneration and renewal that could easily mark the new year. Shouldn't that be the turning point? Government fiscal years end at the same time on March 31.

I suggest that January 1, just after the winter solstice is the fitting time to start anew. Here in the northern hemisphere, our year follows the sun through a cycle of darkness to light and back again. The promise of the sun's return offers a metaphor for the renewal of hope that is represented in the new year.

Summer is coming – that is the message of winter solstice – but enjoy the darkness and winter while it is here. Get out, celebrate light and the season. May it be a merry one for all.

One way to celebrate light in winter is under a full moon, which can "give the luster of mid-day to objects below." The moon is full December 31st. It also happens to be a "blue moon" (second full moon in the same month) and that doesn't happen again until August, 2012.