None of the 46 areas assessed were found to be making "good" progress in adapting to climate change. Only three had "good" plans and policies in place for the future.
These are mostly unchanged from the CCC's last report in 2023.
Health is one of the areas that remains most poorly prepared.
The CCC points to the rising number of deaths linked to extreme heat and hospitals themselves being vulnerable to hot weather.
Baroness Brown highlights the case of Guy's and St Thomas', the biggest hospital trust in London, which was hit by a failure to its data centres during the extreme heat of July 2022.
This meant it was unable to operate its appointments system at a time of intense demand, and it had to move to paper appointments.
"We lost thousands of crucial appointments for people for critical tests," she said.
"We're trying to improve the NHS. Unless we take into account that it has to be resilient to the climate, we're going backwards."
Flooding is another challenging area. Plans and policies to ensure places are resilient to river and coastal flooding are found to have worsened since the CCC's previous report.
The ancient town of Tenbury Wells in Worcestershire is a case in point. It's been flooded repeatedly in the last four years, most recently in November 2024.