Keep an extra layer in your bag even when the morning feels mild

Chinook winds can warm a winter day quickly and the cold can come straight back. I have no clean statistic on how often that happens, so I rely on my own record. The day I left my coat at home in Kensington because the morning felt mild, the afternoon proved me wrong. Now an extra layer lives in my bag all winter, folded small. Check the forecast if you like, but bring the layer.