What Do the Colored Lines and Circles on Typhoon Track Maps Mean?
TyphoonSays·防御问答 · Typhoon knowledge · 更新 at 2026-08-01
Colored Lines: The Typhoon's "Intensity ID"
On real-time typhoon track maps, the winding colored line is not drawn arbitrarily; it intuitively displays the movement trajectory of the typhoon's center and its intensity changes. According to the national standard "Tropical Cyclone Grades" issued by the China Meteorological Administration (CMA), different colors correspond to different wind force levels and destructive potential. Typically, you can identify them as follows:
- Tropical Depression/Tropical Storm: Usually represented by blue or green. At this stage, wind forces are relatively weak, but rainfall may occur.
- Severe Tropical Storm: Typically shown in yellow. Wind forces increase, and you should start paying attention to weather changes.
- Typhoon/Severe Typhoon: Often appears in orange or red, indicating that the maximum wind force near the center has reached Level 12 or above, possessing significant destructive power.
- Super Typhoon: Generally marked in dark red or purple. This is the highest grade of tropical cyclone, with extreme winds and high danger.
This color-gradient line helps you see at a glance whether the typhoon is "intensifying" or "weakening." If the line color changes from light to dark, it means the typhoon's energy is accumulating and the threat is escalating; conversely, it suggests its power may be diminishing.
Probability Circles: The Uncertain "Area of Impact"
Many residents see the large circle at the end of the track and mistakenly believe it represents the exact coverage area or size of the typhoon. This is a common misconception. In meteorology, this circle is known as a "probability circle" or "error circle."
Due to the complex and variable nature of the atmospheric environment, current technology cannot predict the exact position of a typhoon several days in advance with 100% accuracy. Therefore, meteorological experts use numerical models to calculate a statistical probability range. The area within the circle indicates the path where there is a high probability (usually around 70%) that the typhoon's center will pass through.
It is important to note that the larger the circle, the further into the future the prediction is, and the higher the uncertainty. For example, the forecast circle for 24 hours later is usually smaller, while the circle for 72 hours or more into the future will be significantly larger. Furthermore, the actual impact area of a typhoon is often much larger than this circle. Even if your city is outside the circle, you may still encounter strong winds and heavy rain if you are within the typhoon's outer spiral rainbands. Therefore, do not let your guard down just because you are on the edge or outside the circle.
Scientific Defense: From Understanding the Map to Taking Action
Understanding the track map is the first step in disaster prevention, but more importantly, you must take practical action based on warning signals. When the typhoon track points toward your area and the color indicates high intensity, please closely monitor the warning signals issued by local meteorological departments.
Generally, as the typhoon approaches, warning signals escalate from blue and yellow to orange and red. During high-level warnings, it is recommended to take the following measures:
- Reduce Outdoor Activities: Avoid staying near billboards, large trees, or temporary structures.
- Secure Windows and Doors: Check if home windows are secure and clear balconies of clutter to prevent objects from falling.
- Stockpile Supplies: Prepare an adequate amount of drinking water, food, and emergency lighting tools.
Regarding school suspensions and work stoppages, standards may vary by location, so please refer to announcements from local governments. Typically, when a Red Warning is in effect, primary and secondary schools and kindergartens will automatically suspend classes, and some high-risk industries will halt operations. Be sure to obtain the latest instructions through official channels and do not trust rumors. Staying calm and taking scientific precautions is the most powerful weapon against typhoons.
Real-time typhoon tracks can be queried at TyphoonSays (taifengshuo.com)
This article is typhoonsay's original copy content, and the local policy standards are based on the local government's latest release.