Weather follows patterns -- repeating trends that we can observe and learn from. The temperature usually rises during the day and falls at night. Certain months tend to be warmer or colder, wetter or drier. Some places are usually sunny while others get more rain. By tracking weather over time, we can notice these patterns and begin to predict what kind of weather is coming.
Keep a class weather journal for at least a month, recording temperature, sky conditions, and precipitation daily. At the end of the month, look for patterns: which days were warmest? Was there a stretch of rainy days followed by sunny days? Graph the temperatures to make patterns visible. Compare your data with another month or another city.
If you have been watching the weather for a while, you have probably started to notice some things that happen again and again. The morning is usually cooler than the afternoon. Cloudy skies often come before rain. Some weeks have several sunny days in a row, while other weeks bring day after day of gray skies and rain. These repeating trends are called weather patterns.
The simplest pattern is the daily temperature cycle. Every day, the temperature goes up after sunrise as the sun warms the ground, reaches its highest point in the mid-afternoon, and then goes down after sunset as the Earth cools. This pattern happens every single day, even though the exact temperatures are different. On a cloudy day, the high temperature might be lower than on a sunny day -- but the up-then-down pattern still holds.
Patterns also show up over weeks and months. If you live in a place with seasons, you will notice temperatures gradually warming from winter to summer and cooling from summer to winter. You might notice that your area gets more rain in certain months or that thunderstorms happen mostly in the afternoons during summer. These are all patterns that repeat year after year, even though no two years are exactly the same.
Recognizing patterns is how people first learned to predict weather. Farmers noticed that certain cloud shapes often meant rain was coming. Sailors learned that a red sky at sunset often meant fair weather the next day. Today, weather scientists use computers and precise measurements, but the basic idea is the same: look at what the weather is doing now, compare it to patterns you have seen before, and make an educated guess about what is coming next.