Japan weather patterns (overview)
This is a broad overview based on long-term climate patterns and general meteorology. It varies a lot year to year and is separate from this site’s place-by-date statistics. It is not a substitute for forecasts or warnings.
Japan stretches north–south with mountains and surrounding seas, so clear/cloudy/rain tendencies and seasonal rhythms differ by region. Treat the sections below as orientation for travel and daily life—not precise predictions.
By the numbers (representative sites, last 24 years)
From 2002-01-01 through 2025-12-31 (24 full calendar years), we count one “representative weather” label per local day at each representative site below, then show regional totals and a national stack.
The national stack sums day-votes from nine macro regions: eight regions use one site each; Kyushu & Okinawa uses two sites (Fukuoka and Naha), for ten site-streams in total. This is not JMA published statistics—it is based on reanalysis gridded data interpolated to each point.
For each calendar day, we classify each hour at Asia/Tokyo (hours 0–23) with rules version 1.0.0 (same rain/clear/cloudy thresholds as this site’s place-by-date tool), then take the modal category as the day’s label (ties: clear → cloudy → rain). Days without a full set of 24 hourly samples are excluded.
Across that stacked total, valid day-votes summed to 87,660: clear 20,536 (23.4%), cloudy 52,510 (59.9%), rain 14,614 (16.7%).
By region (totals at each representative site)
| Region | Representative site(s) | Clear | Cloudy | Rain | Total votes | Days skipped |
|---|---|---|---|---|---|---|
| Hokkaido | Sapporo | 1,141 (13.0%) | 6,207 (70.8%) | 1,418 (16.2%) | 8,766 | 0 |
| Tohoku | Sendai | 1,523 (17.4%) | 5,848 (66.7%) | 1,395 (15.9%) | 8,766 | 0 |
| Kanto | Tokyo (near Chiyoda) | 2,658 (30.3%) | 4,914 (56.1%) | 1,194 (13.6%) | 8,766 | 0 |
| Hokuriku | Kanazawa | 1,420 (16.2%) | 4,624 (52.7%) | 2,722 (31.1%) | 8,766 | 0 |
| Chubu | Nagoya | 2,999 (34.2%) | 4,603 (52.5%) | 1,164 (13.3%) | 8,766 | 0 |
| Kinki | Osaka (Kita Ward) | 2,528 (28.8%) | 5,168 (59.0%) | 1,070 (12.2%) | 8,766 | 0 |
| Chugoku | Hiroshima | 2,096 (23.9%) | 5,411 (61.7%) | 1,259 (14.4%) | 8,766 | 0 |
| Shikoku | Takamatsu | 2,492 (28.4%) | 5,067 (57.8%) | 1,207 (13.8%) | 8,766 | 0 |
| Kyushu & Okinawa | Fukuoka (Hakata) + Naha | 3,679 (21.0%) | 10,668 (60.8%) | 3,185 (18.2%) | 17,532 | 0 |
Source & definition: Open-Meteo Historical Archive (reanalysis; interpolation varies by location). Same clear/cloudy/rain thresholds as this site. (JSON snapshot date: 2026-04-12)
Clear, cloudy, and rainy tendencies
On the Pacific side, rainy spells often build around the rainy season (roughly June–July) and autumn rain (September–October), while midsummer can see more settled sunshine under subtropical highs. The Sea of Japan side tends toward more cloud, snow, or rain in winter.
When sunshine is most common depends on the region, but stable highs in autumn or right after the rainy season can bring longer fine-weather spells—though typhoons can change the picture quickly.
Seasonal flow (broad strokes)
Spring often brings frequent frontal passages; the mei-yu front advances north into early summer. Summers are hot and humid, with a higher risk of localized thunderstorms.
Autumn can swing between typhoon or autumn-front heavy rain and long stretches of crisp clear skies. Winter monsoon flow and snow-bearing clouds make precipitation (often snow) more common on the Sea of Japan side.
Thunderstorms and typhoons
Thunderstorms are most associated with warm, humid summer air over inland and foothill areas, but spring lows can also be a concern. Think “more common in summer” as a rule of thumb.
Typhoons most often approach or make landfall from July through October. When they interact with autumn fronts, rainfall can become extreme. Okinawa and the Amami area typically face a longer, earlier typhoon season.
Regional notes (very rough)
Hokkaido
Winter brings many cloudy or snowy days, with more precipitation toward the Sea of Japan side. The rainy season is less sharply defined than on Honshu; summers can feel milder overall, though cool summers or heavy-rain years still occur.
Tohoku
The Sea of Japan coast sees heavy winter snow; the Pacific side can still get clearer spells but feels seasonal winds. June brings mei-yu; autumn can add typhoon or frontal rain.
Kanto
Two rainy peaks—mei-yu and autumn fronts—frame hot, often sunny summers and comparatively dry, clear winter spells. Typhoon landfalls vary by year, but combined autumn systems need attention.
Hokuriku
High annual precipitation on the Sea of Japan side: winter snow clouds, and mei-yu fronts that stall for long wet spells. Summer sunshine also varies locally.
Chubu
Sea-of-Japan (Hokuriku-like) and Pacific (Tokai-like) characters diverge; mountain areas include heavy snow belts. Mei-yu, typhoons, and winter snow shift which months feel sunniest by subregion.
Kinki
After the rainy season, heat and thunderstorms pick up; autumn brings typhoon and autumn-front rain. Winter splits between mild Seto Inland–style areas and snowier northern Sea-of-Japan exposure.
Chugoku
San’in faces Japan-Sea winter snow/rain and a wet mei-yu; San’yo leans Pacific-influenced with summer sun and typhoon exposure in places.
Shikoku
Pacific highs and typhoons matter; mei-yu and summer–autumn rain are key. Inland vs coast changes how temperature and rainfall feel.
Kyushu & Okinawa
Kyushu tends to enter and exit the rainy season earlier; typhoon risk runs long from summer into autumn. Okinawa is subtropical with a different rainy-season framing and frequent typhoon approaches.