Farmers across Japan are increasingly shifting their working hours to the night and early morning as more intense heatwaves make daytime agricultural work increasingly dangerous.
In Nikko, Tochigi Prefecture, flower farmer Motoaki Iijima, 36, now harvests gerberas inside illuminated greenhouses after dark to avoid scorching daytime temperatures. He changed his routine three summers ago after a part-time worker suffered heatstroke while picking sunflowers.
Temperatures above 35°C have become increasingly common in the region, while conditions inside greenhouses can climb beyond 40°C. Iijima now carries out much of his outdoor work overnight, stopping when the morning heat becomes too intense.
“We’ve gradually become nocturnal. It’s about protecting our bodies, and ultimately, our lives,” he said.
The shift is not limited to flower growers. Farmers across the world, including those in Vietnam and Spain, are also moving work to cooler hours as extreme heat becomes more frequent and severe.
Japan faces particular challenges because around 70% of its farmers are aged 65 or older, making the workforce especially vulnerable to heat stress. High humidity can further increase the risks associated with extreme temperatures.
The impact has already been reflected in the country’s agricultural sector. A record 59 agricultural workers died from extreme heat in 2024, more than twice the number recorded in 2021.
A survey by the Japan Weather Association last year also found that about 60% of farmers in their 20s to 50s had either experienced heatstroke themselves or knew someone who had. Nearly 60% said they had adjusted their working hours to earlier or later periods of the day.
At Iijima’s farm, workers now begin their shifts up to two hours earlier. Among them is 68-year-old Miyoko Asada, who arrives shortly after sunrise to harvest asters before temperatures rise beyond safer working conditions.
“We’ve got to race against the clock,” Asada said while working alongside other employees in the field.
Extreme heat is also threatening Japan’s livestock farmers. Poultry farmer Tetsuya Usuba, 48, still remembers losing more than 500 laying hens during a three-day heatwave six years ago.
He has since introduced a nighttime routine at his poultry farm, where lights automatically switch on at 2.30am, encouraging his 4,400 hens to eat before temperatures become too oppressive.
Usuba has also installed additional fans, sprays water onto the roofs of his barns and adds citric acid to the birds’ drinking water. Despite these measures, he lost another 130 chickens when temperatures suddenly climbed above 35°C last month.
“Summer has become a new threat to producers like us, something as scary as an outbreak of avian influenza,” he said.
The Japanese government has also introduced measures to address the growing threat. New workplace regulations introduced last year require employers to establish procedures for reporting heatstroke cases and responding to emergencies.
Japan is also promoting smart farming technologies, including drones and robots, to reduce workers’ exposure to extreme heat.
However, many farmers continue to rely heavily on manual labour. At Iijima’s farm, workers race to check flowers for signs of wilting and prepare them for delivery before the morning heat becomes unbearable.
As climate change continues to push temperatures higher, Japan’s farmers are increasingly being forced to rethink not only how they work, but also when they can safely work.
