What qualifies as a heat wave, MET explains

High temperature / FILE

The Kenya Meteorological Department (KMD) has outlined what qualifies as a heat wave in the Kenyan context, as rising temperatures increasingly pose health risks in urban areas.

According to KMD-backed research, a heat wave is defined as a period of three or more consecutive days of extremely high daytime temperatures that exceed locally set thresholds and are linked to adverse health outcomes.

The thresholds are informed by long-term temperature records and health data from major towns, showing a clear relationship between extreme heat and increased hospital visits, admissions and deaths.

Under the proposed heat-health alert system, a heat wave would be declared when some conditions are met.

In Nairobi, a heat wave is triggered when daily maximum temperatures reach 32°C or higher for at least three consecutive days.

In Kisumu, the threshold is 37°C or higher over the same period. In Mombasa, sustained daily maximum temperatures of 36°C or higher for three or more days qualify as a heat wave.

KMD says the differing thresholds reflect local climate conditions and how residents in various regions respond to extreme heat.

Coastal and lakeside cities typically experience higher baseline temperatures, while Nairobi’s cooler climate means lower extremes can still have serious health impacts.

When these thresholds are exceeded, authorities can activate heat-health action plans, including public advisories, emergency response measures and targeted interventions to protect vulnerable groups, such as young children, older persons and people with underlying medical conditions.

The results show positive associations between high temperatures and hospital admissions across the three cities. 

On January 26, Kenya Meteorological Department (KMD) dismissed a heat wave alert circulating on social media, saying it did not originate from the agency.

KMD noted that the high temperatures currently being experienced across parts of the country are normal for the January–March period.

In a statement, the department urged Kenyans to ignore the information on the heat wave alert being passed across on social media.

“KMD would like to clarify that the heat wave alert currently circulating on social media is not an official communication from KMD. We are aware of the message and urge members of the public to ignore it,” the department said .

“As shown in KMD temperature climatology, January, February, and March are typically the hottest months in Kenya, and the warmer-than-average temperatures currently being experienced are normal for this period and consistent with the forecast."

KMD said it will continue monitoring conditions and issue advisories when necessary through its official channels, urging the public not to share unverified weather information.