Making a simple barometer is an easy way to know if you will have clear or rainy weather, according to an article on the Pipex website. To make a homemade barometer, pour 2 cups of water into a jelly jar. Drop in four to five drops of food coloring, mixing it in well. Insert a glass bottle upside down into the jar, and tape it on securely with masking tape. Place the jar outside. If the colored water is low in the bottle, the weather will be rainy and unpleasant. If the colored water rises higher into the bottle, the weather will be sunny and clear.
Making a rain gauge is a simple way to measure how much rain you are getting in your area of the world. Cut off the top of a 2-liter soda bottle, then insert the top of the bottle upside down inside the bottom of the bottle. Tape the top onto the bottom with masking tape. Using a ruler, measure and mark the side of the bottle in 1/2-inch increments using a permanent marker. Place the rain gauge outside. When it rains, the gauge will fill with water and will allow you to measure how much rain has fallen.
An anemometer measures the speed and direction of wind, according to Pipex. You can make a simplified version of an anemometer using foam cups and straws. Curve a piece of florist wire into a circle. Poke one end of the wire through the bottom of one foam cup, sliding it down to the end of the wire. Repeat this process until you have around 15 foam cups in a circle, all facing the same direction. Twist the ends of the wire together to form a closed circle. Attach three pieces of twine onto the circle, then tie them together in the middle. Attach another piece of twine to the middle of the other three pieces of twine. Hang the device outside by the twine. When wind blows, the anemometer will spin around in the direction of that wind.