Weather vs. Climate: What Is the Difference?

Weather and climate are both a part of atmospheric science, but they address different timescales. Weather is the state, or condition, of the atmosphere at a specific point in time (it’s raining today), whereas climate is how the atmosphere generally behaves over longer periods of time (four or more inches of rain is common during the month of March). 

Despite their differences, weather and climate are often mentioned as a pair. So much so, in fact, that 35% of Americans believe the two mean pretty much the same thing, according to a study in the journal Risk Analysis that explores people's perceptions of global climate change.

Let's take a closer look at weather and climate: how they relate to each other, how they differ, and why that difference matters.

What Is Weather?

Weather tells us how the atmosphere is behaving at this very minute, and also how it will behave in the near future — in the upcoming hours, days, and weeks. It is event, location, and time specific.

A number of components make up weather, including moisture, cloud cover, wind speed and direction, air temperature, and air pressure, to name a few. 

Another trait of weather is it changes often. This is because warm fronts, cold fronts, high pressure, low pressure, and other weather systems continually come and go, temporarily altering the atmosphere within a region as they pass through it.

How Weather Is Studied

To study the weather happening outside their door, meteorologists make direct or “in situ” observations using instruments such as thermometers and rain gauges. Every day, over 210 million weather observations are processed in the United States.

To “see” what’s happening across a state, region, or in the next day or so, meteorologists use remote sensing instruments, like weather radar and satellites, which let them gather data from far-off distances. 

When it comes to studying weather that may be several days away, or may not have even developed yet, scientists use weather models — simulations of possible weather scenarios that could take shape based on the weather conditions that currently exist.

At the national level, the National Oceanic and Atmospheric Administration (NOAA) is the agency responsible for monitoring and predicting changes in weather and climate. Within NOAA, its National Weather Service arm provides the public with forecasts and warnings concerning weather in the United States, its territories, and its surrounding bodies of water.

On a global scale, the World Meteorological Organization, which is a United Nations body, leads the international weather, climate, and hydrology (how water impacts Earth’s surface) community. It oversees tasks such as selecting hurricane names, and certifying new weather-related world records.

What Is Climate?

Climate is how the atmosphere habitually behaves, based on observed weather conditions over spans of time such as months, seasons, and years. 

The same components that make up weather also make up climate, except climate looks at averages of these conditions over decades or longer. Long-term weather patterns (for example, El Niño and La Niña) and extreme weather events (a new record hot temperature) also fall under the climate umbrella.

Climate Types

Every location on earth has a climate type — a label that expresses the average weather conditions usually experienced throughout the year. For example, if a region sees high temperatures year-round, it might have a tropical climate. If it rarely sees rainfall, it might have a desert climate. According to the Köppen-Geiger climate classification system, 30 unique climate types exist. The five main types are:

• Tropical
• Dry/Arid
• Temperate
• Cold
• Polar

How Climate Is Studied

In a way, climatologists can be thought of as weather historians. And like actual historians who study ancient times by excavating artifacts, climate scientists gain clues about Earth’s past climates by collecting samples from trees, coral reefs, and ice sheets that record those organisms’ growing conditions. For example, tree rings from the Prometheus tree, one of the oldest-known organisms to man, offer snapshots of rainy, dry, and even wildfire conditions from nearly 5,000 years ago.

Climatologists study present climates by looking at monthly and annual weather observations for trends which might suggest a departure from normal. Like meteorologists, they too depend on model simulations when investigating possible future climate scenarios; scenarios that could result if the rate of greenhouse gas emissions between now and 2100 lowers, stabilizes, or remains at present levels. 

NOAA also leads the monitoring and prediction of climate at the national level. Its Climate Prediction Center issues climate outlooks (forecasts of future weather conditions relative to what's normal for their region), and also monitors and forecasts the onset, strength, and duration of climate patterns including El Niño, the Madden-Julian Oscillation, and others. NOAA’s National Centers for Environmental Information houses more than 37 petabytes of weather and climate data. It also issues State of the Climate reports — monthly and yearly summaries that recap climate-related occurrences on both a global and national scale. 

How Do Weather and Climate Relate?

While weather and climate differ, and it’s important to understand those differences, it’s just as essential to understand how the two are intertwined.  

To illustrate their relationship, consider the expression: You can’t see the forest for the trees. Think of weather as the trees, or the fine details which often distract from the big picture, which is the climate, or forest in our analogy. 

In other words, individual weather observations amass over weeks, months, years, and decades to shape a location’s climate. In turn, climate, which can cool or warm as a result of natural drivers (such as changes in the Sun’s energy output) and human drivers (such as higher emissions of heat-trapping greenhouse gases) can also influence weather in a top-down manner. One example of this is global warming. Our 2.2-degree-F-hotter atmosphere is already triggering a rise in extreme weather events, like hurricanes, heat waves, droughts, and floods.

Here's something else that's important to keep in mind about the weather-climate relationship: Not every hot day is attributable to global warming, and not every cold day counts as evidence that there is no climate crisis. Having a solid understanding of climate (and weather) is key to not making assumptions such as these.