how accurate is 7 day forecast

We all rely on the weather channel to plan our week sometimes, but just how accurate is 7 day forecast?

In this article, you’ll learn the basics of weather forecasting and the accuracies of short, mid-range, and long-range forecasts.

The National Weather Service forecast is accurate about 80 percent of the time: a 7-day forecast can forecast the weather with 80 percent accuracy. On the other hand, a 5-day forecast has an accuracy of 90 percent. However, a 10-day—or longer—forecast is only right about half the time.

The Basics of Weather Forecasting

Forecasting the weather is a complex process that relies on collecting and analyzing all available data about current atmospheric conditions.

There are various models of atmospheric processes applied to make predictions about what the atmosphere will be like at some time in the future.

Advantages of 7-Day Weather Forecasting

advantages of forecast

1. Reliable Weather Information

Weather forecasting is a technology used to predict the weather. It is one of the most critical uses of technology.

With this technology, people have reliably predicted 7-day weather forecasts and measure rainfall or precipitation over a while.

2. Predict Structure of Storms

Meteorologists have widely used a seven-day weather forecast to help determine the structure of a storm.

The information is used to construct profiles of storm activity and place mitigation measures in place.

3. Planning in Research Fields

In meteorology and other scientific research fields, where scientists study how weather systems form and interact, weather information can help experts predict an area’s climate, assisting people to plan.

4. Preparation, Profiling and Provision of Services

A 7-day weather forecast provides people and government institutions with knowledge about the weather in their area so they can plan outdoor activities and schedule outdoor maintenance with confidence.

It also provides them with information about whether a hailstorm is coming so they can protect their populations and property from damage.

Disadvantages of 7-Day Weather Forecasting

disadvantages of forecast

1. Difficulty Forecasting Fog and Wind

Short to midrange weather forecasts do not accurately predict whether fog will occur.

Forecasters have a hard time detecting the presence of moisture from ground-based weather stations.

They can predict the probability that condensation will form but not where or when it may occur.

They are able to use remote sensing for wind detection, but they cannot pinpoint its source without additional information.

2. Intense Datasets

One of the reasons why the question of how accurate is 7 day forecast is in meteorological circles is just the sheer amount of data that has to be processed.

Providing any weather information is generally not easy and requires expertise to analyze the data involved.

A large amount of data associated with the weather forecasts must be examined before any decision can be made.

This process takes time, and information provided by seven-day forecasts is often not real-time, as such information can take up to 24 hours to collect.

How Accurate Is A 7 Day Forecast For Temperature?

accuracy of 7 days forecast

With an accuracy of between 75 and 90 percent, the temperature is critical data set for the weather forecast.

However, climatologists and meteorologists make the best use of technology to give us usable weather information.

Most weather forecasting websites, stations, and experts have an 80% accuracy of a 7-day forecast.

Here are other datasets that are crucial for a 7-day weather forecast:

  • Humidity Data
  • Wind Data
  • Precipitation
  • Atmospheric Pressure

They’ll then use their findings to forecast weather with mathematical models of atmospheric processes.

Note: Climatologists can predict tomorrow's weather to a great degree of certainty if they are given seven or five days' notice.

They can give you a rough idea even if they don’t know which day of the week it will be. The longer the duration, the lower the accuracy drops.

Reliability of Weather Forecasts by Duration

reliability 7 days forecast


Nowcasting is a method of weather forecasting that uses data from several sources, including NEXRAD radar, lightning detectors, and satellites.

All these are used to predict the current weather and forecast the next six hours of conditions. The forecast is often updated each hour.

Short Range Weather Forecasts

Short-range forecasts, which cover times from nowcasting to the next 24-hour forecast and the next two days, are usually 80% accurate.

This accuracy is great when you need a weather report for planning purposes. Note that different weather houses may have different forecasts depending on your location.

It may even be that some sources are using other parameters to forecast weather. 

Medium-Range Weather Forecasts

In the 5-day weather forecast, there is a medium-range forecast for what will happen in the next few days, and dramatic shifts in the weather are standard from one day to the next.

So, the weather forecast for 3 to 10 days ahead can change drastically.

Note: The subsequent few days' weather forecasts provide a general picture of what will happen in that region on a day-by-day basis.

Also, it tries to identify how different parts of the area will differ from each other.

Long Range Weather Forecast

Forecasting the weather beyond ten days is very difficult because the atmosphere is continuously turbulence.

Suppose forecasters cannot predict the weather for the next 15 days with great accuracy.

In that case, they can usually only offer predictions for general trends in our area, such as whether it will generally be warmer, cooler, wetter, or drier than average conditions over the next few weeks.

For example, a forecast of sunny skies for Friday and Saturday night suggests dry roads on Saturday morning.

However, if a storm blows through in the night and it rains on Thursday evening instead of Friday evening, there might be standing water on Saturday morning, making driving dangerous.

Extreme Weather Conditions

Tropical cyclones, hurricanes, typhoons, and tornadoes cause unseasonable weather to occur.

Tropical storms, for example, are followed on a global scale and are often the source of essential updates for local weather forecasts.

A tropical cyclone is an organized system that develops over warm waters and has sustained winds reaching 74 miles per hour or more (i.e. hurricane, typhoon).

How Weather Forecasts are Made

how weather forecast made

After understanding the numbers on how accurate is a 7 day forecast let’s now delve into the various tools and technologies used by forecasters to predict weather patterns over a 7 day period.

Geostationary Satellites

Operated by the National Oceanic and Atmospheric Administration (NOAA), the GOES-R series of satellites has been in production since 2006, orbiting 22,000 miles above the Earth’s surface.

Because they orbit at the same rate that the Earth rotates, allowing them to focus on one spot for most of their time in orbit, the satellites provide near-continuous images over a wide area.

This will enable NOAA to monitor severe weather such as hurricanes as they develop.

Note: Forecasters observe storms, winds and clouds, and their development into a hurricane or typhoons.

They can also gauge where and when extreme weather events will strike.

Deep Space Satellite

The Deep Space Climate Observatory, known as DSCOVR, is a satellite operated by NOAA.

It orbits one million miles from Earth and monitors space weather, solar energy absorption by Earth, ozone and aerosol content in order to forecast air quality.

It also makes observations of Earth’s rotation rate and its effect on the length of day.

Polar Orbiting Satellites

Satellites in the Joint Polar Satellite System orbit Earth at approximately 500 miles.

They travel around the planet from pole to pole, completing two orbits every day.

Because they orbit when the Earth is rotating underneath them—from west to east—they can observe every part of the globe twice in 24 hours.

The satellites regularly monitor terrestrial weather patterns and atmospheric conditions, allowing meteorologists to forecast weather conditions 1–7 days in advance accurately.

Read Next: Does Arizona Get Tornadoes?

Final Thought

Of course, technological advances have helped meteorologists predict the weather more accurately.

However, just like the economy, the weather is always changing, and it is difficult to determine what will happen in the future.

This is especially true with long-range forecasts.

The valid answer to how accurate is 7 day forecast is that it is impossible to pinpoint any future weather conditions a week and beyond.