Painting "plein air"

Now the weather is not so hot, I have been doing some watercolour painting in "plein air", meaning outside. You don't have top go far or to exotic locations to find subject matter.  This is just up the road in a neighbours front garden. Next week I may go to O'Hara Mill near Madoc, Ontario. It has a collection of old homesteaders' houses, school house, lumber mill, etc.
Here is a list of materials that you need when painting "on location" with watercolours:

Watercolour Plein Air Painting Checklist:
• Watercolour paintbox or selection of tubes
• At least one brush
• Pencil and eraser
• Four (rustproof) clips or pegs for keeping your paper in place when it's windy
• Paper towel or cloth for wiping brushes on
• Bottle of water
• Cup for washing brushes
• Watercolour paper
• If necessary, an empty bottle for pouring dirty paint water into, for disposable back home.
Tips: • A largish zippered pencil box or toiletry bag is ideal for putting your brushes etc. in.
• Retractable brushes take up minimal space.
• One of those blocks of watercolour paper where the paper is 'stuck down' is ideal because you don't need to stretch it, but you will need something sharp to separate off a sheet once you're done.
• Consider buying a watercolour field set – a small box of paints complete with retractable brush; some even have waterbottles.