Explained: IMD's colour-coded alerts and what they mean for you

IMD's system uses green, yellow, orange, and red codes to warn citizens about rain, thunderstorms, and severe weather, helping them plan accordingly

The India Meteorological Department (IMD) has forecast active weather conditions across northwest India, including thunderstorms, gusty winds, hailstorms, and isolated heavy rainfall between May 27 and June 1. A red alert has also been issued for Mumbai and three other districts after the city saw over 200 mm of rain today.

 

What are IMD’s colour-coded weather alerts?

 

The IMD uses a colour-coded system—green, yellow, orange, and red—to warn citizens about the severity of upcoming weather. This system helps people prepare and plan ahead for rain, thunderstorms, and other hazards.

 

When are alerts issued?

 

Alerts are issued for various adverse weather events such as rainfall, snowfall, thunderstorms, squalls, hailstorms, dust storms, as well as heatwaves and cold waves. The system is designed to inform the public and minimise disruptions and risks.

 

 

These alerts cover a forecast period of up to five days and are based on the likelihood and impact of the weather event.

 

How are rainfall alerts categorised?

 

For rainfall, alerts are based on the volume of rain expected over a 24-hour period:

 

Green alert: Light rain (less than 64 mm)

 

Yellow alert: 64.5–115.5 mm of rain

 

Orange alert: 115.6–204.4 mm of rain

 

Red alert: Extremely heavy rain exceeding 204.5 mm

 

For thunderstorms, wind speed is the key factor, while for fog and dust storms, visibility and wind speeds are crucial.

 

What do the colour codes signify?

 

Green – No advisory

Weather is generally safe with no action needed.

 

Yellow – Be aware

Potentially adverse weather that could cause minor disruptions; stay updated.

 

Orange – Be prepared

Severe weather likely to affect transport and power; take preparatory measures.

 

Red – Take action

Extremely severe weather that could threaten life and majorly disrupt daily life; immediate safety measures are essential.

 

Where to check IMD weather updates?

 

Readers can stay updated through Business Standard’s daily weather reports and forecasts on businessstandard.com. The IMD also releases an ‘All India Weather Forecast Bulletin’ on its official website.

 

IMD’s weather forecast for northwest India

 

Scattered to fairly widespread light to moderate rainfall is expected across Jammu & Kashmir, Ladakh, Himachal Pradesh, Uttarakhand, Punjab, Haryana, Uttar Pradesh, and Rajasthan this week, accompanied by thunderstorms, lightning, and gusty winds reaching speeds of 40–50 km/h.

 

Himachal Pradesh may see thunderstorms with wind speeds of 50–60 km/h, gusting up to 70 km/h on May 27, 28, 30, and 31, with isolated hailstorms on May 27 and 28.

 

Uttarakhand is likely to experience isolated heavy rainfall from May 28 to 30, while Himachal Pradesh may receive similar heavy downpours on May 30 and 31.

 

Residents in these regions are advised to stay alert and follow safety advisories issued by local authorities.