October 23 marks the Double Ninth Festival, coinciding with the solar term "Frost's Descent" in the traditional Chinese calendar. Experts advise that as autumn transitions into winter, colder temperatures and increasingly dry conditions require the public to dress warmly and prioritize disease prevention.
Astronomy educator and Tianjin Astronomical Society council member Zhao Zhiheng explains that around October 23 each year, when the sun reaches 210 degrees of the ecliptic, marks Frost's Descent—the final solar term of autumn and the beginning of the transition from autumn to winter. By this time, the climate grows progressively colder, with nighttime frosts and chilly mornings bringing the first appearance of white frost.
Ancient Chinese divided Frost's Descent into three phases: First phase—wolves display their prey before eating; second phase—plants turn yellow and shed leaves; third phase—hibernating insects all lower their heads. This signifies wolves displaying captured prey before consumption, leaves turning yellow and falling, and hibernating insects ceasing movement and feeding as they enter dormancy.
Li Yanling, Director of the Nutrition Department at Tianjin University of Traditional Chinese Medicine's First Affiliated Hospital, noted that during Frost's Descent, daily temperature fluctuations are significant, with frequent cold fronts causing sudden drops. The public should dress warmly in a timely manner, strengthen their constitution, and prevent colds.
She specifically advised that adding layers should be based on weather changes, but not excessively—the key is to ensure you don't feel cold.As the saying goes: "Prepare for the third and ninth months when going out," and "For comfort, dress and undress frequently." Therefore, keep several autumn garments on hand to adjust layers as needed.
Li Yanling also advised that during the autumn-winter transition, staying warm isn't just for outdoor activities—preventing colds at home is equally important.For instance: wash your face with cold water to strengthen your body's resistance to cold; frequently air out bedding to let ultraviolet rays kill germs; drink plenty of hot water to boost metabolism; and eat more warming foods to generate body heat.
Dew turns white before the cold sets in.
"The dew turns white before it turns cold." If the White Dew solar term signifies the transition from heat to coolness, then Cold Dew marks the shift from coolness to cold, with lower temperatures and colder ground dew nearing frost formation. As described in the "Collected Explanations of the Seventy-Two Solar Terms": "In the ninth month, the dew grows cold and is about to freeze."
The sayings "Crows roost in trees, osmanthus blooms damp, cold dew withers all grasses" contain no exaggeration whatsoever. Rapid cooling is the most defining feature of Cold Dew's weather. When a strong cold front sweeps through, bringing wind and rain, temperatures plummeting by 8–10°C within a short span is quite common. However, since it is still autumn, the duration of wind and rain is typically brief. Once the cold front passes, temperatures will rise again.
Moreover, during Cold Dew, when temperatures drop significantly and autumn rains occur, atmospheric moisture quickly reaches saturation. This often leads to rain-mist mixtures or dense fog after rainfall, particularly common at night.
Cold Dew Without Chill: Sunny Weather This Week
Though Cold Dew has arrived and northern cold fronts gradually dominate the weather stage, forecasts indicate stable conditions for our city this week.with comfortable temperatures.
This week will primarily feature cloudy skies, with even sunny days being scarce. The absence of scorching sun will make the weather feel relatively pleasant. Temperatures will remain relatively stable, with lows between 15-16°C and highs fluctuating between 23-26°C.
However, persistent clear weather has one drawback: it makes it difficult for dust and particulate matter suspended in the air to dissipate.Checking recent air quality readings, while all classified as "Good," the air pollution index values have been increasing. Generally, mornings tend to have poorer air quality, so those with morning exercise routines should exercise caution.
Additionally, despite this week's stable weather and comfortable temperatures, remember the saying: "After the Cold Dew, thin-clothed men are rarely seen." Even with pleasant weather, it's no longer appropriate to dress as lightly as in early autumn.
Business travelers heading to Northeast China this week should take special note: Moderate cold air will bring strong winds, cooling temperatures, and precipitation across northern China from west to east. Temperatures are expected to drop by 4–8°C, with some northern parts of Northeast China seeing declines of 10–12°C.
It's still too early for mountain climbing, so why not try "autumn fishing by the shore"?
The Cold Dew solar term often coincides with the Double Ninth Festival on the ninth day of the ninth lunar month, giving rise to the long-standing custom of mountain climbing. However, due to this year's leap month, the Double Ninth Festival has left its old friend Cold Dew behind and instead joined its new companion, Frost's Descent.
Without the bustle of mountain climbing, why not settle in for some "autumn fishing along the edges"? As Cold Dew approaches, sunlight loses its intensity, struggling to penetrate deep waters. Sunlit shallow areas remain warmer and teem with plankton, drawing fish to congregate—a phenomenon anglers call "autumn fishing along the edges."
After several autumn winds and rains, temperatures drop again. Shallow waters then become cooler than deeper areas, prompting fish to migrate downward. At this point, it's no longer "autumn fishing along the edges," but rather "autumn fishing in the depths."