What does the blue circle in A Rainy World mean?

Blue indicates precipitation. According to the weather forecast, official website shows. From blue to green, yellow, orange, red, crimson and purple, it shows that the precipitation is getting bigger and bigger. One raindrop on the left has less precipitation, while the three raindrops on the right have more precipitation. The red color near the right end indicates heavy rain or rainstorm. So the blue circle on the rain world map represents precipitation.