We define the seasons by the location of the Sun against the background “celestial sphere” of stars. However, we experience the seasons by the climate and the more immediate day-to-day weather. Weather is driven by the seasons, but there is a lot of variability. So, just because it is winter does not mean it is too cold to enjoy the night.
Over the year, the Sun’s height above the southern horizon varies considerably. It’s very high in the summer (June 22 – the official beginning of summer) and very low on December 22, the beginning of winter. For a month before and after these dates, the Sun is still very high in the summer sky and low in the winter sky, so why not associate a wider range of months with each season?
Seasonal weather systems have inertia. The weather of the previous season seems to linger into the next. Early March is not spring, and May is not summer. On the other hand, we can have snow and frigid weather in November, which is still autumn. Plants and animals all evolved to have a tolerance or “behavioural plasticity” to accommodate weather variations, and so have we.
I don’t pack up my telescope just because it’s winter. I’ve observed in shorts and T-shirts in mid-December – a very rare but delightful experience – and I was still in Canada, not the Caribbean. So, when a warm spell with a clear sky comes along, I try to get out and enjoy nature’s offering. Observing early winter enables us to view a wide expanse of the celestial sphere. The constellations of the “winter sky” can extend in the evening from the setting of the Summer Triangle in west, the culmination of Orion the Hunter around midnight, to the morning rising of Ophiuchus the Serpent Bearer, another summer constellation. So, the winter night sky is buttressed by arguably parts of the summer sky. Indeed, with December 22 having the longest night of the year, in southern Canada we can observe for over 13 hours, or well over half the sky. Compare this to the first day of summer when we can only observe for 1/3 of this time because the nights are so short.
I don’t expect many people to stay up to fully experience a winter night. I did this in my youth – but only once. The occasion was to observe the Geminid Meteor shower that peaks on the night of December 14. Fortunately, observing only an hour or so will be satisfying because moonlight won’t interfere with seeing the fainter meteors. If you have a warm parka, and a few adventurous friends, this is a good year to see these fast and plentiful meteors radiating from the Constellation Gemini. As usual – the darker the sky, and the less light pollution, the better. Also, while outside taking a late evening walk-about, I encourage you to get in the habit of glancing over to the northern sky. The Sun is approaching a period of high “solar activity” that is known to result in displays of the aurora borealis. Y
You can get a heads-up for any potential displays from www.spaceweather.com.
