My daughter is keeping a weather log, tracking temperature, humidity, rainfall amount, and wind direction each day, as well as the time of observation. We made a remarkably easy weather vane from scrap materials: some non-recyclable plastic packaging material that would have otherwise been garbage, a used drinking straw, and old pencil, and a pin.
We used the plastic sheet instead of the manila file folder - it's weather-proof. We stuck the pencil into a clay pot full of soil so it can easily be moved for mowing the lawn. If the gusting midwestern winds blow it to pieces, we'll revise the design.
She loves being a scientist and going outside to the weather station with her clipboard! It's also good fraction practice, since the thermometer and humidity gauges have tenths and the rain gauge has eighths.