While at Lowes Home Improvement the other day I noticed a notepad made of special paper that can be used for pen or pencil in wet conditions.There was a display at the checkout counter.
I still have an all weather pad from John Disley in the UK and have used it from time to time.
I never start a measurement in the rain but have gotten caught more than once. When it starts raining I put my paper notepad away where it will stay dry and use this type of special paper pad.
It works well, doesn't smear and pencil can be erased if needed.
This pad is about 6 in tall, 3 in wide and the pages are graph lined. Cost was around 2 bucks and well worth it if you have ever tried to make sense of blurred ink or pencil tearing paper in the rain.
It is called WeatherMax All-Weather notepad from Hillman Group Cincinnati, OH