Mombasa’s nights are getting hotter — and the city’s residents are feeling it. A new feature explores how rising nighttime temperatures, revealed in the COP30 study, are affecting families in informal settlements, where poorly ventilated homes and limited access to cooling make sleep a daily struggle. Experts and local organisations warn that urgent action is needed to protect health and build resilience against this silent, 24-hour climate threat.
November 13, 2025—The air inside Mariam Salim’s one-room house in Bangladesh slums in Jomvu, Mombasa, feels thick and breathless. A single candle flickers on a wooden stool, throwing shadows on the corrugated walls. Her three children toss restlessly on a shared mattress, sweat glistening on their faces. It is past midnight, but the heat clings to their skin like a heavy blanket.
“Even at night, the house burns,” Mariam murmurs, waving a plastic fan over her youngest child. “We open the door, but it’s like the wind is tired too.”
Across Mombasa’s informal settlements—from Likoni to Kisauni—residents are learning that the nights are no longer a time to rest. Once cooled by the ocean breeze, the coastal city is now enduring nights that feel as hot as the day — a silent symptom of a planet in distress.
Life Inside the Heat
By 10 p.m., the streets of Likoni are quiet, but inside the tin-roofed homes, the heat refuses to relent. In one narrow alley, 12-year-old Juma Hassan lies on a thin mat, turning from side to side, sweat soaking his school uniform. His mother, Aisha, fans him with a small cardboard square, but the effort barely moves the heavy, humid air.
“We open the windows, we pray for wind, but nothing helps,” Aisha says. “Even the ocean breeze doesn’t reach inside our home. Some nights, we barely sleep.”
Just a few kilometres away in Shika Adabu, Likoni Sub-county, Meali Mohammed faces the same long, sleepless nights. She spends hours fanning her two children, aged three and five, with a piece of khanga. “They sweat until their clothes are wet,” she says. “Even after school, when they’ve eaten, the heat is too much.”
The children have developed rashes all over their bodies — a constant reminder of the worsening heat. Her husband, Mohammed Mwachibanda, says they avoid using fans at night, fearing the cold air could make the children sick. “So we just endure it,” he says. “We leave the windows open, but we’re careful — insecurity here in Likoni has also become a worry.”
Across Kisauni and Bangladesh, similar scenes unfold. Children toss and turn, elders gasp for cool air, and small traders who worked under the sun all day retreat to homes that feel like ovens. Many cannot afford fans or air conditioners, and most homes are built with thin tin sheets that trap heat long after sunset.
Local leaders say the crisis is intensifying quietly. “People are suffering silently,” says Hamisi Juma, a community organiser in Likoni. “We see children with feverish nights, mothers unable to rest, and older adults struggling with exhaustion. But the wider public doesn’t see this — it happens when the city sleeps.”
A new study released at the COP30 Local Leaders Forum in Rio de Janeiro warns that Mombasa is among African cities where nighttime temperatures are rising sharply under both humid and dry tropical conditions. Scientists say the shrinking gap between daytime highs and nighttime lows is making heat waves deadlier and robbing millions of their only hours of relief.
What the Science Says
While Mombasa residents sweat through the night, climate scientists are sounding the alarm. A global analysis by Climate Resilience for All, titled “Extreme Heat and the Shrinking Diurnal Range,” examined 100 major cities over the past 30 years. The findings are stark: 83% of cities are experiencing sustained increases in nighttime temperatures, and Mombasa is among those feeling the squeeze of these “hot nights.”
Experts describe this as a shrinking diurnal range — the narrowing gap between daytime highs and nighttime lows. “It’s no longer just the sun that threatens health; the danger now persists through the night,” says Dr. Fatuma Mwangi, climatologist at the Technical University of Mombasa. “When the body doesn’t cool down after a hot day, the risk of heat exhaustion, dehydration, and cardiovascular stress rises significantly.”
Environmentalists say poor urban planning is making things worse. Khamisa Maalim Zajjah, Coast Regional Director at Maji na Ufanisi, a sanitation and environmental NGO, warns that Mombasa’s skyline is slowly choking the city’s natural airflow from the Indian Ocean.
“Mombasa will face tough times if development continues without planning,” she says. “Tall buildings have blocked the air spaces that once carried the ocean breeze across the city.”
Zajjah cites recent findings from the Intergovernmental Panel on Climate Change (IPCC) confirming that ocean tides are rising — putting Mombasa at risk of both extreme heat and flooding. She notes that the county continues to approve skyscrapers of up to 15 floors, despite environmental warnings to limit structures to four storeys.
[Environmentalist and Maji na Ufanisi, a sanitation and environmental NGO, Coast Regional Director Khamisa Maalim Zajjah. She warns that Mombasa’s skyline is slowly choking the city’s natural airflow from the Indian Ocean while poor urban planning worsens the situation. Photo/Ahmed Omar/November, 13, 2025].
“The perennial heat will only be solved through proper planning, transparency, and the involvement of all stakeholders,” she adds.
Health and Safety Concerns
The danger of Mombasa’s hot nights goes beyond discomfort — it’s becoming a public health emergency.
“When people cannot cool down at night, their bodies fail to recover from daytime exposure,” explains Dr. Joseph Mwamburi, a public health officer at Mombasa County. “We see more dehydration, heat exhaustion, and cardiovascular issues, especially among children and the elderly.”
Local clinics report spikes in emergency visits during prolonged heat periods. Many cases involve dizziness, fainting, or fatigue — signs of accumulated heat stress.
The Kenya Red Cross notes that most heat-related illnesses in informal settlements go unreported. “Many residents simply endure the nights without seeking medical help,” says Grace Odhiambo, a Red Cross community coordinator. “Poor ventilation, overcrowding, and lack of healthcare access make nighttime heat a silent threat.”
Women, often responsible for late-night chores and childcare, face an even greater burden. “Extreme heat doesn’t just affect health — it changes daily life,” Odhiambo adds. “It’s a gendered crisis as much as it’s an environmental one.”
What Can Be Done
While the situation is alarming, experts and local officials insist it is not hopeless.
Emilly Achieng Okello, Mombasa’s Water, Environment, Energy and Natural Resources CECM, acknowledges that the city is under mounting pressure. “Mombasa is facing a lot of heat,” she says. “Being an island surrounded by the Indian Ocean — with dense human activity — we expect temperatures to keep climbing.”
Okello says the county is implementing its Climate Change Action Plan (2023–2050) to address heat, flooding, and urban resilience. “We’re restoring green spaces, planting trees along major streets, and involving locals in adaptation efforts,” she notes. “Last year we had a scare — cyclones and flooding. Mombasa is no longer preparing for a distant future. We are reacting to climate shocks already at our doorstep.”
[Mombasa’s Water, Environment, Energy and Natural Resources CECM, Emilly Achieng Okello joins Mombasa resident in planting trees. She acknowledges that the city is under mounting pressure facing a lot of heat. Photo/Ahmed Omar/November, 13, 2025].
Community-based interventions also show promise: reflective roofing, shaded compounds, improved ventilation, and tree planting campaigns are providing small but vital relief.
As Dr. Fatuma Mwangi emphasizes, “Even simple measures — lighter roofing materials, better ventilation, and green corridors — can bring real change if done collectively.”
The COP30 study serves as a stark reminder: climate change is not only about rising seas or daytime heatwaves — it’s also about the oppressive nights that silently threaten lives. For Mombasa’s informal settlements, every night without relief is a call for urgent, human-centered action.
