IMD considers cold wave conditions using a station's minimum temperature and its departure from normal. The starting threshold is 10°C or below in the plains and 0°C or below in hilly regions, followed by the applicable cold wave test. For plains stations, an actual minimum of 4°C or below is one cold wave criterion, and 2°C or below is a severe cold wave criterion.
This seasonal guide, checked on 4 November 2026, explains the terminology in the India Meteorological Department's cold wave FAQs. A chilly morning or a falling temperature alone does not establish an official declaration. The published criteria also consider departures from normal, geographical setting and persistence across stations.
| Test | Published threshold |
|---|---|
| Initial minimum temperature threshold | 10°C or below in plains; 0°C or below in hills |
| Cold wave by departure | 4.5°C to 6.4°C below normal |
| Severe cold wave by departure | More than 6.4°C below normal in the current bulletin legend |
| Cold wave by actual minimum, plains | 4°C or below |
| Severe cold wave by actual minimum, plains | 2°C or below |
What does IMD mean by departure from normal?
Departure compares a recorded temperature with the normal for that location and period. It is different from the change since yesterday. A temperature can fall sharply over a day yet remain close to normal. Conversely, a fairly small daily change can leave a station substantially colder than its usual seasonal conditions.
For a hypothetical plains example, a minimum of 8°C against a normal of 13°C is 5°C below normal. It meets the initial temperature threshold and falls within the cold wave departure band. This is an illustration of the arithmetic, not an observation for any city on 4 November. The actual classification remains IMD's responsibility.
The department's FAQ adds a persistence requirement for declaring a cold wave: the criteria should be met at at least two stations in a meteorological subdivision for at least two consecutive days, with declaration on the second day. One screenshot from one neighbourhood cannot establish that regional requirement. A station observation and an area warning answer different questions.
Cold wave and cold day: what is the difference?
A cold wave is assessed using minimum temperature. A cold day concerns the departure of maximum temperature, while also meeting the initial minimum temperature condition. IMD lists a maximum temperature departure of 4.5°C to 6.4°C below normal for a cold day, and more than 6.4°C below normal for a severe cold day.
That distinction helps explain why a place can have an unusually cold afternoon without its lowest temperature falling to the severe cold wave threshold. Maximum and minimum readings describe separate parts of the daily temperature cycle. Read the actual term in the bulletin rather than substituting a general description such as bitter cold.
Coastal stations have another published condition. A cold wave may be described when the minimum temperature is 15°C or below and its departure is at least 4.5°C below normal. Applying only the 4°C plains figure to every Indian location would therefore miss part of IMD's framework. The location and the type of test must be read together.
What does the 4 November 2026 bulletin show?
The Delhi daily bulletin issued at 20:45 IST on 4 November 2026 records Safdarjung's minimum as 16.1°C in its observation table ending at 17:30 IST. Its departure from normal is positive 0.8°C. That particular observation does not meet the plains cold wave temperature threshold described above.
This is a dated example of reading the table, not a declaration about all of India or an assessment of every Delhi neighbourhood. The same bulletin separates actual temperature, departure and change over 24 hours into different columns. Checking the column heading prevents a daily fall being mistaken for a below normal departure.
How to check a cold wave warning for your area
Use the official Cold Wave Guidance page, which links daily impact based bulletins, an extended outlook, monthly and seasonal outlooks, and an interactive temperature map. Begin with the issue date and the valid date. A seasonal outlook describes a different period from a daily warning and should not be used as a forecast for a particular morning.
The FAQ explains that IMD provides colour coded warning information and a map covering the next five days. Match the named area with the place where you will actually be. Recheck the latest bulletin before an early departure or outdoor activity, particularly if the original information came from an old message or cropped map.
Wind can increase the impact of cold exposure through wind chill, which IMD discusses separately from the thermometer reading. Its preparedness advice includes keeping winter clothing ready, using multiple layers, staying dry and taking particular care of children and older people. Serious discomfort or symptoms after cold exposure require medical attention. These precautions do not replace local instructions during a warning.
Related local reporting includes a past Uttar Pradesh low visibility report, an earlier Varanasi cold weather report, and the NTES train running status guide. Earlier local reports should be read with their original dates; they are not today's warnings.
