It’s an important question: What do I wear to a protest march in January?

Thousands of women are committed to march in solidarity in Washington DC and around the country – on a January day. Here in MA our march will be in Boston and we can expect similar weather. This article has received a lot of attention because women are creatures of preparation. The author has updated it after receiving even more information from readers.
Thousands are expected to come to Washington DC on January 21st to march on the first day of incoming President Donald Trump’s administration. As someone who lives in the area and attended rallies and inaugurations at this time of year I can tell you it’s going to be cold, you’re going to be on your feet for a long while, and basic necessities like bathrooms and bottled water are few and far between. What’s a woman to wear when sending a message to the government that women’s rights are human rights?
Update: After many questions, I have more details about the march and the content of this piece at the bottom of this post. I have also updated the tips thanks to many of you who have written in.
(get advice about what to wear in the full article on the blog, “Wardrobe Oxygen” here: http://www.wardrobeoxygen.com/2016/12/what-to-wear-to-a-protest-march.html)