Climate change in Hamilton Kirikiriroa

The climate in our city is already changing, including longer summers, warmer temperatures, extreme rainfall, and drought. Climate modelling shows that for Hamilton Kirikiriroa, we’ll experience:

Our city is getting warmer and projected to get warmer still. To understand what this increase in heat will mean for Hamiltonians and the city, we’ve started exploring the Urban Heat Island (UHI) effect. This is where urban areas experience higher temperatures than surrounding rural areas, particularly at night. It is caused by cities having more dense infrastructure and darker surfaces, such as asphalt and concrete. These dark surfaces soak up heat during the day and release it at night. Human activities like driving, running air conditioning units, and other industrial processes in cities release artificial heat. The UHI effect amplifies increased temperatures and heatwaves brought on by the changing climate.  

An assessment of UHI for Hamilton Kirikiriroa completed in 2025 showed there is an obvious effect in our city. Hotspots identified are the central city, around Waikato Hospital, and the University of Waikato, as these areas have high proportions of buildings and concrete and limited vegetation.  

Urban hotspots were up to 5°C warmer than the coolest parts of the city. We also found that during the summer of 2024–2025, Hamilton Kirikiriroa experienced a notable heatwave, with maximum temperature extremes exceeding 27°C for 15 consecutive days. During this heatwave, on 6 February 2025, areas of the central city and around the hospital reached 40°C. That’s pretty hot! 

We're now working to better understand the UHI effect and improve our heat data. From this, we will include heat reduction approaches and responses to extreme heat events into our planning and policies. 

Find out what we’re responding to climate change