Tokyo Weather Guide: Navigating the July Heat and Haze

The Seasonal Transition: From Tsuyu to Mid-Summer

In July, Tokyo undergoes a dramatic atmospheric shift. The first half of the month is typically defined by the tail end of Tsuyu (the "plum rain" season). During this period, the sky is often a persistent, soft gray, and the air is heavy with moisture. You won't often see dramatic thunderstorms; instead, expect a steady, relentless drizzle that can last for hours, keeping the city in a damp, humid embrace.

By mid-to-late July, the rainy front usually retreats, and the Japanese Meteorological Agency officially declares the end of the rainy season. This transition is abrupt and intense. The clouds break, and the city is hit by the full force of the Pacific High—a high-pressure system that brings bright, blazing sunshine and a sharp spike in temperature. This late-July period is when the "real" Japanese summer begins, marked by the iconic sound of cicadas (semi) buzzing in every park.

Daily Rhythms and the "Urban Heat Island"

Tokyo’s climate behaves with a predictable, sweltering rhythm in July.

• Mornings: Even at sunrise (around 4:30 AM), the air is rarely "crisp." Humidity levels often peak in the early hours, making the air feel thick before the sun even climbs.
• Afternoons: Between 11:00 AM and 3:00 PM, the heat becomes most intense. Tokyo’s status as a massive concrete metropolis creates a significant Urban Heat Island effect. The asphalt and skyscrapers absorb solar radiation throughout the day, radiating heat back into the streets. In the city center, temperatures can feel 2–3°C hotter than in the greener suburbs.
• Evenings: Do not expect a significant "cool down" after sunset. The retained heat in the buildings prevents the temperature from dropping sharply. Evenings are often "tropical nights" (nettaiya), where temperatures stay above 25°C (77°F), accompanied by high humidity that makes strolls through the neon-lit districts of Shinjuku or Shibuya feel electric but steamy.

Local Weather Phenomena

• Yudachi (Evening Showers): A classic July phenomenon is the yudachi—sudden, torrential late-afternoon downpours. These aren't the steady rains of Tsuyu, but short, violent bursts of rain caused by rising heat. While they provide a momentary drop in temperature, the resulting evaporation often makes the air feel even more "sauna-like" immediately after.
• The Sea Breeze: Areas closer to Tokyo Bay, such as Odaiba or Toyosu, may experience a slight afternoon sea breeze. While this provides some air movement, the humidity coming off the water means it offers little in the way of actual cooling.

Sensory Experience: The Humidity Impact

In Tokyo, the numbers on the thermometer are secondary to the dew point. With relative humidity often hovering around 80%, the body’s ability to cool itself via perspiration is significantly hindered. The heat doesn't just feel "hot"; it feels "heavy" and "sticky." Locals describe this feeling as mushi-atsui (humid-hot/steamy).

To adapt, you will notice locals carrying small electric hand fans or traditional sensu, and using tenugui (thin cotton towels) to constantly dabbing away beads of moisture. The transition between the oppressive outdoor heat and the aggressive, ice-cold air conditioning found in department stores and subways is a constant sensory feature of traveling through the city in July.