Japan’s Winter 2026–27 Forecast: A Record El Niño, a Likely Warmer Winter and Less Snow on the Sea of Japan Coast

The Pacific is running hotter than it ever has. In early October, the Japan Meteorological Agency (JMA) said the El Niño that began this spring had become the strongest since its records began in 1949, and that it will almost certainly last through the winter. JMA’s seasonal forecasts point the same way for Japan: a warmer-than-normal winter is the most likely outcome in most of the country, with less snow than normal favoured along much of the Sea of Japan coast. Here is what the forecasts actually say, what they don’t, and what it could mean if you are planning a winter trip.

Every figure below comes from JMA’s own forecasts and reports. Links are at the end.

The short answer

• A record El Niño

  Sea temperatures in JMA’s El Niño monitoring region were 4.0°C above the reference value in September 2026, beating the previous record of 3.6°C set in December 1997.

• It should last all winter

  JMA puts the chance of a record-strength El Niño continuing into winter at 100%.

• Warmer is the best bet

  For December to February, JMA gives a 60% chance of above-normal temperatures in eastern and western Japan and 70% in Okinawa and Amami. In northern Japan, near normal and above normal are tied at 40%.

• Less snow is favoured

  On the Sea of Japan side of eastern and western Japan, the most likely outcome is less snow than normal (50%). In northern Japan, less or near-normal snow are tied at 40%.

• Greyer on the Pacific side

  JMA expects fewer sunny days than normal on the Pacific side, which includes Tokyo, and above-normal precipitation in eastern Japan’s Pacific side, western Japan and Okinawa.

• Odds, not promises

  These are probabilities. A 60% chance of a warm winter still leaves a real chance of a normal or cold one, and cold snaps can happen in any winter.

What has El Niño got to do with Japan’s winter?

El Niño is a warming of the sea surface in the central and eastern equatorial Pacific. It shifts where the tropics release heat and rain, and that ripples through weather patterns around the world, including over Japan.

JMA tracks it with a monitoring index: the sea surface temperature in a box of the eastern Pacific, compared with the average of the previous 30 years. JMA counts an El Niño when the five-month running mean of that index stays at +0.5°C or more for six months or longer.

This year’s numbers are extraordinary. In its report of October 9, 2026, JMA said the September value was +4.0°C, above the previous high of +3.6°C from December 1997 and the highest in records going back to 1949. The five-month running mean for July was +2.6°C. JMA expects the record-strength El Niño to continue through winter, with 100% probability (JMA, El Niño Outlook, October 9, 2026).

One caution: JMA also said that in September, El Niño’s usual fingerprints were not clearly visible in Japan’s weather, and pointed readers to its latest seasonal forecasts for what comes next. A record in the Pacific does not automatically mean a record anywhere in Japan.

Will winter 2026–27 be warm in Japan?

Probably warmer than normal in most of the country, but not everywhere with the same confidence.

JMA issued its cold-season forecast for December to February on September 18, 2026. When it published the three-month forecast on October 20, it reviewed that outlook against the newest data and said it had not changed (JMA, seasonal forecast, October 20, 2026).

JMA forecasts in three categories, below normal, near normal and above normal, each defined so that it happened in exactly a third of winters from 1991 to 2020. So with no information at all, every outcome would get 33%. Anything well above 33% is a real signal (JMA, the three categories).

December 2026 to February 2027, average temperature. JMA cold-season forecast, issued September 18, 2026, unchanged on October 20, 2026.

In practical terms, Tokyo, Osaka, Kyoto, Hiroshima and Fukuoka all sit in regions where a warm winter is nearly twice as likely as in an average year, and a cold one is rated at just 10%. Sapporo and Sendai are in northern Japan, where JMA sees near normal and warm as equally likely.

What about November, December and January?

The October 20 three-month forecast covers November to January. For the period as a whole, JMA gives above-normal temperatures a 50% chance in northern Japan and 60% in eastern Japan, western Japan, and Okinawa and Amami.

Month by month, the signal is strongest in November:

JMA three-month forecast, issued October 20, 2026.

If you are coming for the late autumn leaves, a warmer-than-normal November matters. Leaves turn when nights get cold, so check the latest colour reports in our koyo guide rather than relying on average dates.

Will there be less snow in Japan this winter?

Less snow than normal is the most likely outcome along much of the Sea of Japan coast, the side of the country that normally gets the heaviest snow.

For December to February, JMA gives:

• Eastern Japan, Sea of Japan side (the Hokuriku region: Niigata, Toyama, Ishikawa and Fukui): 50% chance of less snow than normal, 20% chance of more.
• Western Japan, Sea of Japan side (excluding northern Kyushu): 50% less, 20% more.
• Northern Japan, Sea of Japan side (the Sea of Japan side of Hokkaido and Tohoku, such as Akita and Yamagata): less than normal and near normal are tied at 40%, with 20% for more.

Two things to keep in mind. First, these are regional totals for the whole season. They say nothing about any single storm, and a mild winter can still bring a heavy snowfall on a given week. Second, JMA’s seasonal forecast does not give separate figures for individual mountains or ski areas. If you are booking a ski trip, check each resort’s own snow reports closer to the time.

Will Tokyo have a rainy winter?

It may be greyer than usual. Winter on the Pacific side is normally the sunny half of Japan, but for December to February JMA expects fewer sunny days than normal on the Pacific side of northern, eastern and western Japan.

Precipitation follows the same pattern. JMA gives a 50% chance of above-normal precipitation for December to February on the Pacific side of eastern Japan (which includes Tokyo), across western Japan, and in Okinawa and Amami. On the Pacific side of northern Japan, near normal and above normal are tied at 40%.

On the Sea of Japan side of western Japan, JMA expects more cloudy, rainy or snowy days than normal. In northern and eastern Japan’s Sea of Japan side, it expects the usual run of cloudy, snowy days. Okinawa and Amami are likely to see more cloudy and rainy days than normal.

Is this what usually happens in an El Niño winter?

Partly. JMA has studied Japan’s weather in El Niño winters from 1947/48 to 2020/21, with the long-term warming trend removed from the temperature figures. The statistically meaningful tendencies it found for December to February were (JMA, Japan’s weather in El Niño years):

• Temperature: near normal or warm in western Japan.
• Precipitation: more than normal on the Pacific side of eastern Japan and in Okinawa and Amami.
• Sunshine: less than normal on the Pacific side of western Japan, and near normal or less on the Pacific side of eastern Japan.

The 2026–27 forecast lines up with those patterns: warmer in the west, wetter and greyer on the Pacific side. But El Niño is only one input, and JMA’s forecast is based on its full prediction system, not on El Niño alone. Past El Niño winters were also weaker than this one, so history is a guide, not a template.

How reliable are seasonal forecasts?

They are honest about uncertainty, which is the point. JMA’s guidance explains that a 60% chance of “above normal” means that, if the same forecast were issued 100 times, about 60 of those seasons would turn out warm. It also means about 40 would not (JMA, how to read the probabilities).

JMA checks its own record this way. Its published verification for three-month forecasts from 2020 to 2024 compares the probabilities it issued with how often each outcome actually happened (JMA, forecast accuracy).

So use the forecast to tilt your plans, not to bet on them. Pack for a normal Japanese winter, and treat a mild one as a bonus.

What does this mean for a winter trip to Japan?

• 1

  Still pack for winter

  Warmer than normal is still winter. Bring layers, a warm coat and shoes that cope with wet streets.

• 2

  Expect more wet days on the Pacific side

  Tokyo and much of the Pacific coast may see more rain and fewer clear days than usual. A compact umbrella earns its place.

• 3

  Check snow close to the date

  Less snow is favoured on much of the Sea of Japan coast. For ski trips, follow resort reports and keep flexible plans.

• 4

  Watch the updates

  JMA’s one-month forecast comes out every Thursday at 14:30 JST, and the next three-month forecast is due on Tuesday, November 24 at 14:00 JST.

• 5

  Book busy dates early

  The weather won’t change the calendar. New Year (Shogatsu) is one of the busiest travel times, and many businesses close for a few days, as our peak travel periods guide explains.

FAQ

Will winter 2026–27 be warmer than normal in Japan?

Probably, in most regions. JMA gives a 60% chance of above-normal temperatures from December to February in eastern and western Japan and 70% in Okinawa and Amami. In northern Japan, near normal and above normal are tied at 40%.

How strong is the 2026 El Niño?

It is the strongest on JMA’s records. In September 2026, sea temperatures in JMA’s El Niño monitoring region were 4.0°C above the reference value, beating the previous record of 3.6°C from December 1997. Records go back to 1949.

Will there be less snow in Japan this winter?

Less snow than normal is the most likely outcome on the Sea of Japan side of eastern and western Japan, at 50%. In northern Japan’s Sea of Japan side, less and near-normal snow are tied at 40%. The forecast does not cover individual ski areas.

Will Tokyo be rainy this winter?

JMA expects fewer sunny days than normal on the Pacific side, which includes Tokyo, and gives a 50% chance of above-normal precipitation from December to February on eastern Japan’s Pacific side.

Does El Niño always make Japan’s winter warm?

No. JMA’s statistics show that El Niño winters tend to be near normal or warm in western Japan, with more precipitation on eastern Japan’s Pacific side. It is a tendency, not a rule, and other factors also shape each winter.

When will JMA update the winter forecast?

JMA issues a one-month forecast every Thursday at 14:30 JST. The next three-month forecast, covering December to February, is due on Tuesday, November 24, 2026 at 14:00 JST. The next El Niño update is due on November 10, 2026.

Bottom line

A record El Niño is shaping up in the Pacific, and JMA’s forecasts lean towards a warmer, greyer winter for much of Japan, with less snow favoured along much of the Sea of Japan coast. It is a lean, not a certainty. Pack for winter, keep an eye on the updates, and enjoy it if the mild weather arrives.

Sources and further reading

• Japan Meteorological Agency (JMA) — El Niño Outlook, October 2026 to April 2027 (English) (October 9, 2026: NINO.3 +4.0°C in September, above the previous record of +3.6°C from December 1997; record El Niño to continue through winter, 100%; next update November 10, 2026); El Niño monitoring report No. 409 (Japanese) (October 9, 2026: no clear El Niño features in Japan’s September weather)
• JMA, seasonal forecasts — Three-month and cold-season forecasts for Japan (Japanese) (three-month forecast for November to January issued October 20, 2026; cold-season forecast for December to February issued September 18, 2026 and confirmed unchanged on October 20, 2026); Forecast calendar (Japanese)
• JMA, how seasonal forecasts work (Japanese) — The three categories (normal = middle third of 1991–2020); Reading the probabilities; Forecast regions; Forecast accuracy
• JMA, climate statistics — Japan’s weather in El Niño years (Japanese) (winters 1947/48 to 2020/21)
• The Japanist — Japan’s autumn leaves (koyo) guide; Japan’s 2026 peak travel periods

Method note: All probabilities are JMA’s, as published on October 26, 2026. “Normal” means the middle third of 1991–2020 values for each region and season. Region names follow JMA’s forecast areas; the prefectures listed are examples. Seasonal forecasts describe regional averages and cannot predict the weather on a particular day or at a particular place.