What Is La Nina? How the Cool Pacific Phase Drives U.S. Weather
What is the weather phenomenon known as La Niña, how is it different from El Nino, and what does it mean for our weather? Find out!
Quick Reference
- What it is: a band of unusually cold sea-surface water along the equatorial Pacific. La Nina is the cool counterpart to El Nino. Both are phases of the El Nino Southern Oscillation (ENSO).
- How often: La Nina events occur every 3 to 5 years, typically lasting 9 to 12 months. They often (but not always) follow on the heels of an El Nino.
- U.S. winter signature: colder and snowier than average across the Northeast, Upper Midwest, and Pacific Northwest. Drier than average across the Southwest, Gulf Coast, and Florida.
- Atlantic hurricane impact: the season runs more active. The atmospheric pattern reduces wind shear over the tropical Atlantic, allowing more storms to form and intensify.
- Most recent La Nina: the long “triple-dip” La Nina ran from autumn 2020 through March 2023, the only triple-year La Nina on the modern record. The current cycle (April 2026) is in ENSO-neutral conditions transitioning toward El Nino, not La Nina.
La Nina is the colder, less-discussed half of the El Nino Southern Oscillation cycle. Where El Nino warms the equatorial Pacific and shifts U.S. weather patterns into “wet south, mild north,” La Nina cools the same waters and pulls the country’s weather pattern in the opposite direction: colder and snowier in the north, drier and warmer in the south, with a much more active Atlantic hurricane season layered on top. Here is what La Nina is, how it shapes the U.S. weather year, what the past several events have produced, and how the current ENSO cycle (April 2026, in transition) is shifting away from La Nina rather than toward it.
What La Nina Actually Is
La Nina is a sustained cooling of sea-surface temperatures across the central and eastern equatorial Pacific Ocean. The same Nino 3.4 box that NOAA uses to track El Nino (5 degrees North to 5 degrees South latitude, 170 to 120 degrees West longitude) is the area watched for La Nina. When the Nino 3.4 sea-surface temperature runs more than 0.5 degrees C below the long-term average for three consecutive months, NOAA declares La Nina conditions. When that cool anomaly persists for five overlapping three-month periods, it is officially classified as a La Nina event.
The cooler-than-normal water comes from intensified easterly trade winds. In a La Nina, the trade winds blow harder than usual, which pushes warm surface water westward more aggressively and pulls colder deep water up to the surface along the eastern Pacific. The cold upwelling is stronger, the western Pacific warm pool is more concentrated, and the contrast between the two ends of the equatorial ocean is sharper. That contrast drives the global atmospheric reorganization that produces La Nina’s downstream weather effects.
Where the Name Comes From
“La Nina” is Spanish for “the little girl,” chosen as the deliberate counterpart to “El Nino” (“the little boy” or “the Christ Child”). The name was adopted in the late 20th century as climate scientists formalized the back-and-forth pattern of equatorial Pacific warming and cooling. Originally, the cold phase was called by various less-poetic terms (anti-El Nino, El Viejo, “non-El Nino”), but La Nina won out by the 1980s as the symmetry with El Nino became the dominant framing.
The full ENSO label (El Nino Southern Oscillation) treats the warm and cool phases as two sides of a single oscillating system. The “Southern Oscillation” half refers to the back-and-forth in atmospheric pressure between Indonesia and Tahiti that drives the surface temperature anomalies. La Nina, in this framing, is the phase when Indonesian pressure runs low and Tahitian pressure runs high; El Nino is when the pattern reverses.
A Normal Year vs. a La Nina Year
Compared with a typical (ENSO-neutral) year, a La Nina year features:
- Stronger easterly trade winds, pushing warm water westward more aggressively.
- Cold-water upwelling along the eastern Pacific (Peruvian coast) running stronger than usual.
- More concentrated heavy rainfall over the western Pacific (Indonesia, the Philippines, northern Australia).
- A polar jet stream that shifts north and intensifies over the Pacific Northwest, delivering more frequent and stronger Pacific storms to the region.
- Reduced upper-level wind shear over the tropical Atlantic, allowing hurricanes to organize and intensify more easily.
- A weaker subtropical jet stream over the southern U.S., reducing winter storm activity across the Southeast and Gulf Coast.
The combined effect is a U.S. weather pattern that “intensifies the usual.” Areas that are normally cold and snowy in winter (Upper Midwest, Pacific Northwest, Northeast) get colder and snowier. Areas that are normally dry in winter (Southwest, southern Plains, Florida) get drier. The pattern produces some of the country’s most punishing winter conditions in the north and some of its worst drought conditions in the south, often in the same season.
La Nina’s U.S. Regional Impact
The La Nina pattern is mirror-image symmetric with the El Nino pattern across most of the U.S. The regional signal during a moderate-to-strong La Nina:
- Pacific Northwest (Washington, Oregon, Idaho, western Montana): wetter and cooler than average. Mountain snowpack runs above normal. Strong ski seasons. Risk of flooding when warm spells melt the snowpack quickly.
- California: drier than average, especially central and southern California. Reservoir levels run below average. Wildfire risk in the following summer is often elevated.
- Southwest (Arizona, New Mexico, southern Nevada, west Texas): drier than average. Drought conditions deepen. Multi-year La Ninas have produced some of the worst Southwestern droughts on record.
- Central Plains and Upper Midwest: colder than average, with above-normal snowfall in the Dakotas, Minnesota, Wisconsin. Increased frequency of Alberta Clipper events.
- Southeast (Florida, Georgia, Alabama, the Carolinas): warmer and drier than average. Reduced winter storm activity. Drought risk during the dry winter months.
- Northeast and New England: colder than average. Snow accumulation often runs above normal, especially across upstate New York, Vermont, New Hampshire, Maine. Increased frequency of polar vortex disruptions.
- Tornado Alley (Plains and Mid-South): spring tornado season is often more active during La Nina years, with the strongest tornadoes (EF3+) occurring more frequently.
- Atlantic hurricane season: notably more active than average. Reduced upper-level wind shear allows storms to intensify and persist longer.
For the season-by-season impact on your region, the Farmers’ Almanac long-range forecast incorporates the ENSO state into its zone-by-zone outlook. For the contrasting El Nino pattern, see our what is El Nino piece. For the official NOAA reference and current Nino 3.4 readings, see the NOAA Climate.gov La Nina explainer.
Why La Nina Boosts Atlantic Hurricane Activity
La Nina years consistently produce more active Atlantic hurricane seasons than ENSO-neutral or El Nino years. The mechanism: La Nina conditions reduce the upper-level westerly wind that flows across the tropical Atlantic during summer and fall. That weaker upper wind reduces vertical wind shear (the difference in wind speed between the surface and 30,000+ feet) that can disrupt forming storms. With less shear, hurricanes can organize their circulation more cleanly and intensify more rapidly.
The 2020 hurricane season (during the early phase of the 2020-2023 triple-dip La Nina) produced 30 named storms, the most active Atlantic season on record. The 2010 La Nina season produced 19 named storms and 12 hurricanes, also among the most active on record. Conversely, the strong 2015-2016 El Nino produced one of the quietest hurricane seasons in recent memory at 11 named storms and 4 hurricanes. La Nina years are reliably the years to watch the tropical Atlantic closely. For the upcoming hurricane name list and what to expect from each year, see our hurricane names reference.
A History of Recent La Nina Events
Notable La Nina events over the past several decades:
- 1973-1976: the longest recorded La Nina on the modern instrumental record, lasting nearly three years. Produced major U.S. drought and contributed to global famine and flooding events.
- 1988-1989: a moderate-to-strong event that produced the Midwestern drought of 1988 (one of the worst in U.S. history) and contributed to a notably active 1989 hurricane season including Hurricane Hugo.
- 1998-2001: a long multi-year La Nina that followed the strong 1997-1998 El Nino. Produced the active 1999 and 2000 hurricane seasons, including Hurricane Floyd.
- 2007-2008: a moderate event producing notably active 2007 and 2008 hurricane seasons, including Hurricane Gustav.
- 2010-2012: a moderate-to-strong event including the active 2010 hurricane season and the historic 2011 Joplin tornado spring.
- 2020-2023 (the “triple-dip” La Nina): the only three-consecutive-winter La Nina on the modern record. Spanned the 2020-2021, 2021-2022, and 2022-2023 winters and concluded in March 2023. Produced the historic 2020 Atlantic hurricane season (30 named storms), severe Western U.S. drought, and a sequence of three colder-than-average Northeastern winters.
Multi-year La Ninas like the 1973-1976 and 2020-2023 events are unusual but not unprecedented. They tend to produce cumulative effects (deepening drought, reservoir depletion, multi-season cold) that single-year La Ninas do not.
Where the Current Cycle Stands (April 2026)
The U.S. is not currently in a La Nina. The 2020-2023 triple-dip La Nina ended in March 2023. The 2023-2025 El Nino followed and concluded in April 2025. The current state, as of mid-April 2026, is ENSO-neutral, with a slow warming trend pointing toward an El Nino emergence in late spring or early summer 2026 rather than a return to La Nina.
For the Pacific Northwest and Northeast in particular, this means the 2025-2026 winter just concluded ran milder than the previous three La Nina winters, and the upcoming 2026-2027 winter is currently expected to lean warmer if the projected El Nino arrives on schedule. The next La Nina in the rotation will likely arrive sometime in 2027 or 2028 once the developing El Nino runs its course; ENSO oscillation lookups suggest a moderate-to-strong La Nina by 2028 is among the more likely outcomes, but predicting that far ahead with confidence is beyond current model capability.
La Nina Impacts Beyond U.S. Weather
La Nina affects more than U.S. winter forecasts. The cooling of the equatorial Pacific reorganizes weather patterns globally:
- Australia: wetter than normal across most of the country. La Nina years often produce major flooding in Queensland, New South Wales, and Victoria. The 2010-2011 floods were among the worst in Australian history, occurring during a strong La Nina.
- Southeast Asia and Indonesia: wetter than normal. Flooding is common during strong La Nina events.
- South America: drier than normal across much of Argentina, Uruguay, and southern Brazil, where La Nina droughts can damage soybean and corn crops. Wetter than normal in northern Brazil and parts of Colombia and Venezuela.
- East Africa: drier than normal across much of Kenya, Somalia, and southern Ethiopia, often producing severe drought during multi-year La Nina events.
- Indian monsoon: usually stronger than normal, with above-average rainfall across India and Pakistan.
- Pacific fisheries: the Peruvian anchovy fishery, which suffers during El Nino, often thrives during La Nina because the cold-water upwelling that sustains it runs stronger than normal.
The global cascade is one reason La Nina has measurable economic impacts in tens of billions of dollars annually, comparable to El Nino in scale though distributed differently across regions.
How to Use the La Nina Forecast
For practical planning, the La Nina state is one of the strongest seasonal forecast inputs available. The signal is most useful for:
- Heating fuel planning: a La Nina winter typically runs colder in the northern U.S. than an ENSO-neutral or El Nino winter. Stocking heating fuel earlier and topping off reserves makes sense.
- Hurricane prep: a La Nina hurricane season runs more active. Coastal residents in the Atlantic and Gulf basins should review evacuation plans and supply kits earlier than usual.
- Water resources: a La Nina winter delivers above-normal precipitation to the Pacific Northwest and below-normal to California and the Southwest. Western farmers and water utilities adjust accordingly.
- Travel and recreation: Pacific Northwest and Northeastern ski resorts often have stronger seasons during La Nina; California ski resorts run drier.
- Agriculture: southern Plains and Southeastern farmers face elevated drought risk during La Nina winters and springs; Plains and Midwest farmers face the opposite.
Used as one input alongside the long-range forecast and other seasonal signals, La Nina is one of the most actionable seasonal-forecast variables. The Farmers’ Almanac long-range forecast incorporates the ENSO state every season; the next published outlook for the 2026-2027 winter will reflect the developing El Nino rather than a continued La Nina pattern, and the regional impact will read as the mirror image of the past three winters in many zones.
La Nina is not a sweet little girl, despite the name. It is the colder, drier, more storm-prone half of the ENSO cycle, and when it dominates, the country’s weather gets sharper at both ends: more snow in the north, more drought in the south, and more hurricanes in the Atlantic. The current cycle is moving past it. The next one will be along soon enough.
Frequently Asked Questions
Are we in a La Nina now?
No. As of April 2026, the equatorial Pacific is in ENSO-neutral conditions, transitioning toward El Nino. The most recent La Nina (the 2020-2023 triple-dip) ended in March 2023. The 2023-2025 El Nino followed and ended in April 2025.
How is La Nina different from El Nino?
La Nina cools the equatorial Pacific; El Nino warms it. The U.S. winter impacts are roughly opposite: La Nina brings colder, snowier winters to the north and drier conditions to the south, while El Nino brings the opposite pattern. La Nina also makes Atlantic hurricane seasons more active; El Nino makes them quieter.
How long does La Nina last?
9 to 12 months is typical, but multi-year La Ninas occur. The 1973-1976 event lasted nearly three years, and the 2020-2023 “triple-dip” La Nina spanned three consecutive winters.
When will the next La Nina happen?
Probably 2027 or 2028 at the earliest, after the developing El Nino runs its course. The ENSO cycle does not run on a fixed schedule, so confident predictions for events more than a year ahead are not possible with current models.
Does La Nina cause hurricanes?
Not directly, but La Nina conditions make the Atlantic hurricane season more active by reducing upper-level wind shear over the tropical Atlantic. The 2020 La Nina-influenced season produced a record 30 named storms.
How does La Nina affect winter weather in the Northeast?
Colder and snowier than average. Snow accumulation in upstate New York, Vermont, New Hampshire, and Maine often runs above normal. The polar vortex is more likely to disrupt and send Arctic air south during La Nina winters.
What was the longest La Nina on record?
The 1973-1976 event, which lasted nearly three years. The 2020-2023 “triple-dip” La Nina was the only three-consecutive-winter La Nina on the modern record, although individual cool periods within it dipped to neutral conditions briefly between winters.
This article was published by the Staff at FarmersAlmanac.com. Any questions? Contact us at questions@farmersalmananac.com.
- Farmers' Almanac Staff
- Farmers' Almanac Staff
- Farmers' Almanac Staff
- Farmers' Almanac Staff
is la nina bad or good or neither is el nino bad or good or neither
USAclimatereporter – Both El Nino and La Nina can have positive effects in some areas and negative in others, depending on what kind of weather you want. They’re just different.
El Ninos tend to force the jet stream south, making the south much cooler and wetter than normal, meaning the north US and Canada is warmer. So what was so unusual about the la nina last winter? I thought they forced the cold air farther north (the opposite of el nino) shouldnt La Ninas cause us to have warm winters anyway? 2000 was our warmest winter on record and that was a La Nina year! Im confused
Even if you believe God created the earth and the rest of the universe, I believe, He/She probably has better things to do than worry about our weather. Don’t you think
that was probably all set into motion at the same time as he created our universe? We are so egotistical. Give thanks to God if you believe him, but don’t expect him to have time for the problems that you haved created for yourself. That’s why he gave us “free choice” as the Bible teaches.
Out here in the midwest we had horrible droughts. NOTHING grew! Unless it was in the melon family. Was this drought a result of El Nino or La Nina? What will next summer hold?
The Bible says God controls the rains and wind and everything weatherwise, so we are all just playing a guessing game. Yes, God is in control.
just want to say love the farmers almanac
OK SO THE WEATHER PREDICTORS THINK THAT THEY UNDERSTAND THE WEATHER AND CAN PREDICT IT , WRONG YOU ARE 97% RIGHT 3% OF THE TIME !! MY GUESS IS WE WATCH THE ANIMALS AND THEY WILL TELL YOU WHEN THE WEATHER IS GOING TO CHANGE , AFTER ALL THE SPEND 100% OF THERE TIME OUT IN THE OPEN THINK ABOUT IT!!!!
Well, all this subject (article and comments) are a kind of treason on Farmer’s Almanac, for sure! During decades the weather was no mistery to its editors in the US as in Brazil, were I live, there was a Folhinha Mariana that by unknown methods was a sure guide about the rains and dry seasons.
Today each time we know more (about any subject), we learn that actually we need to know much more. So we – at the end – know less.
I remember a Mark Twain quote about the weather that is each day more actual:
“Everybody talks about the weather but nobody does anything about…”
I think the people from a long time ago had it figured out. We cannot figure out El Nino and La Nina, with all of our sophisticated computers and incredible computer modeling. Those old timers didn’t have all the computer stuff to figure it out. They were settled in the fact that it was El Nino! The Christ! In other words, God is in control of the weather. He designed it. And, some things that God does we will never be able to figure out, simply because we are not as smart as He is.
Does this have anything to do with the 2012 prophecy predicted by the Mayan civilisation?
Fergi, No, Southern Oscillation has nothing to do with the Mayan calendar. We’ve known about it for more than 150 years, and it’s likely been happening for much, much longer than that. It’s just part of nature, like anything else.