We are independent & ad-supported. We may earn a commission for purchases made through our links.
Advertiser Disclosure
Our website is an independent, advertising-supported platform. We provide our content free of charge to our readers, and to keep it that way, we rely on revenue generated through advertisements and affiliate partnerships. This means that when you click on certain links on our site and make a purchase, we may earn a commission. Learn more.
How We Make Money
We sustain our operations through affiliate commissions and advertising. If you click on an affiliate link and make a purchase, we may receive a commission from the merchant at no additional cost to you. We also display advertisements on our website, which help generate revenue to support our work and keep our content free for readers. Our editorial team operates independently of our advertising and affiliate partnerships to ensure that our content remains unbiased and focused on providing you with the best information and recommendations based on thorough research and honest evaluations. To remain transparent, we’ve provided a list of our current affiliate partners here.

What is an Undercurrent?

Mary McMahon
Updated Jun 04, 2024
Our promise to you
All Things Nature is dedicated to creating trustworthy, high-quality content that always prioritizes transparency, integrity, and inclusivity above all else. Our ensure that our content creation and review process includes rigorous fact-checking, evidence-based, and continual updates to ensure accuracy and reliability.

Our Promise to you

Founded in 2002, our company has been a trusted resource for readers seeking informative and engaging content. Our dedication to quality remains unwavering—and will never change. We follow a strict editorial policy, ensuring that our content is authored by highly qualified professionals and edited by subject matter experts. This guarantees that everything we publish is objective, accurate, and trustworthy.

Over the years, we've refined our approach to cover a wide range of topics, providing readers with reliable and practical advice to enhance their knowledge and skills. That's why millions of readers turn to us each year. Join us in celebrating the joy of learning, guided by standards you can trust.

Editorial Standards

At All Things Nature, we are committed to creating content that you can trust. Our editorial process is designed to ensure that every piece of content we publish is accurate, reliable, and informative.

Our team of experienced writers and editors follows a strict set of guidelines to ensure the highest quality content. We conduct thorough research, fact-check all information, and rely on credible sources to back up our claims. Our content is reviewed by subject-matter experts to ensure accuracy and clarity.

We believe in transparency and maintain editorial independence from our advertisers. Our team does not receive direct compensation from advertisers, allowing us to create unbiased content that prioritizes your interests.

An undercurrent is a type of current which runs below the surface of air or water currents. The direction of an undercurrent is typically opposite that of surface currents, and the strength of the undercurrent varies, depending on the situation and the circumstances. Meteorologists often consider undercurrents when making predictions, and the study of undercurrents is an important part of the field of oceanography as well, since undercurrents play a major role in the water cycle which mixes the world's oceans.

In terms of meteorology, undercurrents can have a dramatic effect on the weather, pulling clouds and storm systems in unexpected directions. Many undercurrents are charted, so meteorologists can account for them when examining weather phenomena, while others may arise spontaneously in response to changing climatic conditions, potentially wreaking havoc. Undercurrents are part of the larger system of air circulation and patterns which creates global weather, and explains why storm systems move in the way that they do, and how the weather of various regions on Earth is created.

In bodies of water, multiple undercurrents can sometimes be found under surface currents. In the open ocean, undercurrents tend to remain very stable, making them easy to study. The largest undercurrent system is that which drives the thermohaline circulation system of the ocean, which brings upwelling lightweight, warm water from the equator to the poles, where it slowly becomes colder and more dense, sinking to the bottom and then flowing back towards the equator, where it will upwell again thousands of years later.

Surface ocean and air currents actually interact with each other; you can look at a chart of ambient air currents mapped over ambient ocean currents for an illustration. By studying the pattern of surface currents in an area, scientists can sometimes make predictions about the undercurrents, also sometimes known as sub-surface currents. These predictions are usually based on a pattern of recorded undercurrents in the region, along with a consideration of the factors that may affect these currents.

Swimmers have to be especially careful of undertows, undercurrents which run in the opposite direction of surface currents. An undertow can sometimes be much stronger than a surface current, and very unexpected. Beaches with known undertows and rip currents usually post signage to warn people to be careful in the water. Some areas have well known undertows; along the coast of North America, for example, a powerful undercurrent runs parallel to the shoreline. This undertow sometimes switches directions, making it hard to recover people and cargo lost close to the shore.

All Things Nature is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.
Mary McMahon
By Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a All Things Nature researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

Discussion Comments
By DylanB — On Jul 26, 2012

@shell4life – The thought of being pulled out to sea by an undercurrent terrifies me! I have always loved swimming in the ocean, but there is a certain amount of fear that goes along with it.

I always respect the signs put out by beach personnel. When the sea is choppy and the winds are high because storms are approaching, they usually put out yellow flags. You can still go in the water when yellow flags are up, but they signify a moderate risk of rip tide, and I don't want to take the chance, so I stay out.

Some days have been so rough that there are two red flags placed on the beach. This means that no one is allowed in the water, because even the best of swimmers is likely to get tugged away by the undertow.

By wavy58 — On Jul 25, 2012

I define undercurrent as an unspoken feeling of anger. I never knew that it was actually related to weather and water, because I had only heard it used when referring to the mentality of a group of people.

I had a terrible boss years ago, and everyone despised him. The undercurrent at the restaurant where we worked was one of resentment, and we all had a feeling that one day, there would be a revolution.

He finally did something to upset us so much that we all quit on the spot. He had a restaurant full of impatient customers and no one to serve them. Our hostile undercurrent had been transferred to them, and the boss actually ran away from his own business!

By healthy4life — On Jul 24, 2012

I've always heard that when cold air and warm air collide, you get severe thunderstorms. I guess that the undercurrents are what pull those air masses together.

I live in tornado alley, so I am always weather alert. I have a storm shelter out front, and my local TV stations all jump on the case when severe weather approaches.

I always watch the weather forecast, and when I see two air masses of drastically different temperatures coming together, I know we will be in for a rough time. The meteorologist can tell by the undercurrent what will likely happen, but I usually pray he is wrong.

By shell4life — On Jul 24, 2012

My great-grandfather was killed by an undercurrent in 1946. He had been swimming off of a peninsula in Florida, and the water was rough that day.

The two men who had been with him had also gotten caught in the undercurrent. They knew to swim parallel to shore until they broke free, but my great-grandfather panicked and tried to swim to shore. He got swept further out, and his body washed up days later a few miles down the beach.

I know that the two men felt horrible about being unable to save him, but they knew that if they attempted to swim out, they would likely die, too. It was a terrible situation for everyone involved.

Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a...

Learn more
All Things Nature, in your inbox

Our latest articles, guides, and more, delivered daily.

All Things Nature, in your inbox

Our latest articles, guides, and more, delivered daily.