Where I live in the D.C. area, we have had an all-time record for rainfall this year - over 66 inches and counting, where the average is 43 inches. I have had to measure in some wet weather over the past few months. I found a handy little case for my notepad, draft map, sheet protectors, and pens:
I attached a small metal wire basket to my handlebars, into which I place this case. I hold it in an upright position with a couple of cable ties attached to the basket. I place my draft map in a clear sheet protector and clip it onto the outside of the case. The calculator seems to have worked OK in wet conditions so far. I carry a spare inside the case. This has been a big help.
