Biking 6:05:00  152.88 km (25.1 kph) +394m
The plan for today was to repeat my Niagara trip of August 8. The skies were clear, the moon was full, and my weekend was free of plans. Unfortunately, the low temperature forecast for the trip was 4 C, and even as I was setting out, it was 5-6 C in Toronto.
I prepared in the usual way: clothing was SLS shirt, quarter tights, and a windbreaker in reserve; about 5000 calories with 3 Kit Kats, 4 granola bars, 180g of goldfish, 200g of M&Ms, a sandwich, and the usual 3.75 L of gatorade. I carried two innertubes and my usual mechanical kit.
Immediately upon setting out, I felt cold. I resolved to go for an hour to give myself a chance to warm up. Getting low on my aerobars helped my stay warm by reducing my exposure to the wind. I felt ok physically for the first hour, but when I stopped in Oakville at 1:29/41 km, I immediately started shivering. Given that completing this trip basically tested my limits of endurance, I figured that the energy drain from being cold would put the expedition in serious jeopardy. While my core was generally warm enough, my extremities were quite cold. I couldn't seem to keep my calves warm, and my lower legs were cramping when I planted my foot at traffic lights.
Anyway, after my fueling stop, I resolved to cut my trip by about half. I picked Burlington as my turnaround point, but as I hit Burlington, I decided to add a circuit of Hamilton Harbour. This was fine, but the temperature continued to fall, and I was quite cold at my second break at 4:09/110 km despite putting on my jacket at 80 mins. The rest of the trip home was a bit of a struggle, but my return was inevitable. The sun started to come up at about 5:00 into the trip, but I was unable to really push, as I apparently had already drained my available energy reserves.
The lesson here is pretty clear: nighttime starts are difficult when the temperature drops below 10-12 C. A 7 am start today might have been feasible, though the more limited daylight makes 12h expeditions questionable.