There are 365 days in a year and 24 hours in a day. This makes for 8,760 hours in a year. Multiply that into minutes and it brings us to 525,600 minutes. And each one of those minutes brings us different weather.

No day is identical to another when it comes to the forecast or observed conditions. Yes, they can be similar, but it’s very difficult for it to be identical.

Why? Because there are many factors that go into a day’s weather. For examples, temperature, dew point, wind, cloud cover, sunshine, cloudy, humidity, rain, was it sunny to start the day, was it cloudy, was it a warm night, was it a clear night… the list goes on and on.

And each one of these factors change every day, if not every hour or minute.

So why does weather change?

First, the weather is the state or condition of the atmosphere at any given time.

There are different air masses spread out throughout the world and when these air masses move, they mix. And this creates the changes.

If a high and low pressure move and mix then the wind speeds change and so could the wind directions.

If a low pressure system is moving towards a high pressure, you can generally expect cloudier conditions. This may also bring in cooler air and precipitation.

If it were the exact opposite, a high pressure moving towards a low pressure, then you can generally expect clearing skies, warming temperatures, and lighter winds.

This is a general rule of thumb, just because it doesn’t always work this way. Sometimes the changes aren’t drastic at all and it just depends on the strength of the systems or the changing air masses. If they were both strong, you’ll see a noticeable difference/change in weather conditions. If both air masses are weak then it could be a slight difference over a long period of time.

Of course, each circumstance is different.

Different moving air masses are the main reason why weather changes, but there are also others factors. Astronomical factors.

It can also depend on the length of daylight and season.

If you’re in the winter months, in the northern hemisphere, then you can expect shorter and colder days. This will not allow for the atmosphere to warm up as fast. Now, change over to the summer months. The days are a lot longer and this provides more time for day time heating and this can warm up the atmosphere and thunderstorms can develop.

These are just a few examples as to how everything weatherwise can change at any moment. It can be by season, month, day, hour, and minute. After all, with how tornadoes form, like we learned in a recent blog post, you need a change in air masses and a tornado can develop almost instantly.