Cold Northerly Winds Return Wednesday Night, Then a Sharp Warm-Up Over the Three-Day Weekend

Overview: Mild Wednesday Afternoon, Colder Air Arrives Tonight

Japan is seeing comparatively higher temperatures on Wednesday afternoon, but the pattern is expected to change quickly. From Wednesday night onward, northerly winds are forecast to turn noticeably colder. This shift will be felt widely, including on the Pacific side where the chill is expected to become more apparent later in the evening.

Along the Sea of Japan side, precipitation is expected to increase, with more locations seeing snow or rain. In mountainous areas in particular, there is a risk that snowfall could temporarily intensify. The forecast also highlights the need for caution as conditions evolve from mild daytime weather into a colder, more wintry setup overnight.

Sea of Japan Side: More Snow and Rain, With Localized Hazards

On Wednesday afternoon, the number of places experiencing snow or rain is expected to increase on the Sea of Japan side. Conditions may become more active from Hokuriku into late Wednesday night, where there is a risk of thunderstorms and sudden, hazardous weather.

Specifically, Hokuriku is expected to require attention through late night for:

• Lightning
• Sudden gusts
• Hail

These hazards can occur even when temperatures are not extremely low, and they can make travel and outdoor activities more difficult. People in affected areas may want to keep an eye on changing conditions, particularly as precipitation and wind increase.

North Japan: Strong Winds, Blowing Snow, and Increasing Mountain Snowpack

As winds strengthen, parts of northern Japan are expected to see blizzard-like conditions. The forecast notes that some areas may experience blowing snow, and that snowfall accumulation could increase from Wednesday night into Thursday morning, especially in mountainous regions.

This combination of strengthening winds and accumulating snow can reduce visibility and make conditions more severe than snowfall alone. In areas prone to drifting or sudden whiteout conditions, even short trips can become challenging as the weather turns more wintry.

Pacific Side: The Cold Becomes More Noticeable Late Wednesday

While the Sea of Japan side contends with increasing precipitation, the Pacific side is also expected to feel the change. The forecast indicates that the later it gets on Wednesday night, the more the coldness of the wind will be felt. Even in places not seeing snow, this wind shift can make the air feel significantly colder compared with the relatively mild conditions earlier in the day.

For many communities, the most noticeable change may be the contrast between Wednesday afternoon and late evening: a milder daytime period followed by a sharp return to winter-like chill after dark.

Thursday: Snow Area Narrows, But Cold Conditions Persist Nationwide

By Thursday afternoon, the area affected by snow along the Sea of Japan side is expected to shrink. However, the overall temperature pattern remains on the cold side across the country. Even on the Pacific side from the Kanto region westward, morning and evening cold is expected to be significant enough that winter precautions remain necessary.

This means that even if precipitation becomes less widespread, the cold itself will continue to shape daily conditions. Commuters and anyone spending time outdoors may need to plan for a winter-like feel during the early and late parts of the day.

Dry Air on the Pacific Side: Fire Safety Concerns, Especially in Kanto

The forecast also points to very dry air on the Pacific side. Kanto, in particular, is expected to be extremely dry. Dry conditions can increase the risk of fires spreading more easily, so extra care is advised when handling flames or heat sources.

Even when skies are clear, dryness can be an important part of the weather story. With cold air and low humidity, small ignition sources can become more dangerous, so caution is encouraged in daily routines that involve fire.

Cold Through Friday Morning, Then a Daytime Recovery Begins

The colder-than-usual conditions are expected to continue through Friday morning, with a notable chill in many areas. After that, a gradual daytime recovery is anticipated. The forecast suggests that even in northern Japan and Hokuriku, temperatures will begin to rise during the day on Friday.

This sets the stage for a larger shift heading into the upcoming three-day weekend. The key feature of the forecast is not only the cold spell itself, but the size of the temperature swing that follows shortly afterward.

Three-Day Weekend: Temperatures Rise Quickly Across Japan

During the three-day weekend, many places are expected to see a sharp increase in temperatures. The forecast indicates that on Saturday, eastern and western Japan are likely to exceed 15°C. On Sunday, temperatures are expected to rise further across a wide area.

By Monday (the holiday), some parts of Kanto, including Tokyo, may approach around 20°C. This marks a significant warm-up compared with the winter cold expected through Friday morning, and it underscores how quickly conditions can change over just a few days.

Health and Daily Life: Preparing for Large Temperature Swings

A rapid transition from cold to warm can be physically demanding. The forecast specifically warns about the burden that sharp temperature changes can place on the body. This can be relevant for anyone adjusting clothing, heating use, and activity levels across the week.

Practical planning may involve dressing in layers and being mindful that mornings and evenings can still feel colder even as daytime temperatures climb. The overall message is that the weather will not be stable: it will move from relatively mild, to sharply colder, and then to noticeably warmer again during the holiday period.

Heavy-Snow Regions: Avalanche and Falling Snow Risks Increase With Warming

In areas with substantial snow cover, the warming trend over the three-day weekend brings additional concerns. The forecast highlights the need for increased caution regarding avalanches and falling snow as temperatures rise.

When temperatures climb quickly, snow conditions can change in ways that make slopes and snow-covered structures more hazardous. The forecast emphasizes that regions with heavy accumulated snow should remain especially vigilant as the weekend warm-up progresses.

Monday (Holiday): Stronger Winds in Northern Japan and Potentially Rough Weather

While much of the three-day weekend is expected to be warmer, the forecast notes a separate concern for Monday in northern Japan: winds are expected to strengthen. With stronger winds, the weather may become rough, and attention is advised for changing conditions.

This means that even as temperatures rise in many areas, wind-driven impacts could still affect plans in the north. The overall outlook for the holiday period is therefore a mix of spring-like warmth in some regions and more unsettled, windier conditions in others.

Key Points to Watch

• Wednesday afternoon is relatively mild nationwide, but colder northerly winds are expected from Wednesday night.
• Snow or rain is expected to increase along the Sea of Japan side; mountain areas may see temporarily stronger snowfall.
• Hokuriku faces a risk of lightning, sudden gusts, and hail through late Wednesday night.
• Northern Japan may see blizzard-like conditions as winds strengthen; mountain snowfall accumulation could increase into Thursday morning.
• By Thursday afternoon, the snow area is expected to narrow, but temperatures remain low nationwide; morning and evening cold persists even on the Pacific side.
• Dry air is expected on the Pacific side, especially in Kanto, raising fire safety concerns.
• The cold continues through Friday morning, but daytime temperatures begin to rise afterward.
• Over the three-day weekend, temperatures rise quickly: Saturday above 15°C in eastern and western Japan, warmer still on Sunday, and near 20°C in parts of Kanto on Monday.
• In heavy-snow areas, warming increases the risk of avalanches and falling snow.
• On Monday, winds strengthen in northern Japan, bringing a risk of rough weather.

Outlook

The forecast for the coming days is defined by change: a turn toward colder northerly winds from Wednesday night, lingering winter cold through Friday morning, and then a rapid warm-up across much of the country during the three-day weekend. Along the way, localized hazards—such as thunderstorms in Hokuriku, blowing snow in the north, and very dry air in Kanto—add additional factors to consider.

For those making plans, the most important theme is variability. Conditions may shift quickly not only from day to day, but also within the same day, especially between daytime warmth and nighttime chill. In snow-covered regions, the warming trend brings its own set of risks, making continued caution necessary even as temperatures climb.