Major Heat: intense sun, farmers labor in fields
Major Heat (dashu), the twelfth of the twenty-four solar terms and the sixth and final solar term of summer. Falling on July 22-24 each year when the sun reaches 120° of ecliptic longitude, Major Heat marks when many regions enter the hottest period of the entire year. Summer damp-heat becomes prominent and severe convection occurs frequently, requiring balanced attention to both heat prevention/cooling and flood prevention/drainage.
China's southeastern coast frequently experiences typhoon activity, requiring close monitoring of typhoon tracks and their wind and rain impacts. Jiangnan and South China regions suffer from high temperatures and oppressive humidity with afternoon thunderstorms common; North China and the eastern portion of the Northwest see alternating high temperatures and severe convection. Both cities and rural areas must strengthen waterlogging prevention and drainage, and ensure power supply and disaster prevention safeguards.
First Aspect - Decayed Grass Becomes Fireflies: Decomposed grass transforms into fireflies; summer nights shimmer with the glow of countless firefly lights.
Second Aspect - Soil Moist, Oppressive Heat: Soil moisture combined with rising heat creates steamy, oppressive conditions—the "sultry heat" (溽暑) of legend.
Third Aspect - Heavy Rains Fall in Time: Severe convection and torrential downpours occur in succession; guard against thunderstorms, strong winds, and sudden intense precipitation.
Rest: Sleep late and rise early with midday rest; avoid intense midday sun and high-temperature work; maintain room ventilation and cooling, and if necessary, use air conditioning to eliminate dampness.
Diet: Emphasize light, easily digestible foods that clear heat, generate fluids, fortify the spleen, and eliminate dampness. Favor winter melon, bitter melon, lotus root, mung bean soup, lotus leaf congee, Job's tears, and seasonal fruits and melons; minimize spicy, fried, overly sweet, and cold beverages.
Exercise: In early morning or evening, engage in gentle aerobic activity such as walking, tai chi, and swimming, maintaining mild perspiration and paying attention to hydration and electrolyte balance to prevent heat stroke.
Emotions: Summer damp-heat can easily cause irritability and fatigue; emphasize clearing the heart and calming the spirit through quiet sitting and breathing exercises, enjoying brief nature outings and viewing lotus flowers to soothe the heart.
Major Heat Lamb: In some regions, eating lamb during the dog days is a tradition for health supplementation and dampness elimination, symbolizing vigor and safe passage through the heat.
Dog Days Tea for Cooling: Drinking green tea or herbal cooling tea, sour plum juice, and grass jelly drinks to clear summer heat and generate fluids.
Airing Books and Paintings: A folk tradition involves drying books, paintings, texts, and clothing to prevent moisture and mold.
Viewing Lotus and Harvesting Roots: Enjoying lotus flowers in ponds, harvesting and tasting fresh lotus root—symbols of coolness, elegance, and seeking auspicious blessings and protection.
Major Heat follows Minor Heat and precedes the Beginning of Autumn. Its key characteristics are peak summer heat and intense damp-heat interaction, with severe convection and typhoon season coinciding—requiring balanced attention to heat prevention and disaster mitigation.
Astronomical Significance: At Major Heat, the sun reaches 120° of ecliptic longitude. Although daylight is slightly shorter than at Summer Solstice, ground heat accumulation reaches its peak and human heat stress is highest.
Agricultural Guidance: In southern regions, focus on water and fertilizer management during rice panicle emergence and flowering, pest control, and prevention of high-temperature heat damage and heavy rain waterlogging; in northern areas, monitor corn and soybean for drought and flooding, and in protected agriculture, strengthen ventilation and cooling while reinforcing structures against wind.
