South Island solar by town: Where solar works best in the South Island
The short answer
Blenheim tops the South Island for solar yield at about 1,390 kWh per kW a year, followed by Kaikōura, Christchurch and Nelson; Westport sits lowest at about 1,090. So 100 kW of panels makes roughly 109,000 to 139,000 kWh a year, depending on where it sits.
The data
Solar yield by town
| Town | Region | kWh per kW a year | What 100 kW makes a year | June vs December |
|---|---|---|---|---|
| Blenheim | Marlborough | 1,390 | 139,000 kWh | 58% |
| Kaikōura | Canterbury | 1,370 | 137,000 kWh | 52% |
| Christchurch | Canterbury | 1,340 | 134,000 kWh | 50% |
| Nelson | Nelson Tasman | 1,340 | 134,000 kWh | 58% |
| Rangiora | Canterbury | 1,330 | 133,000 kWh | 52% |
| Motueka | Nelson Tasman | 1,320 | 132,000 kWh | 56% |
| Ashburton | Canterbury | 1,300 | 130,000 kWh | 56% |
| Timaru | Canterbury | 1,290 | 129,000 kWh | 49% |
| Oamaru | Coastal Otago | 1,260 | 126,000 kWh | 53% |
| Twizel | Canterbury | 1,250 | 125,000 kWh | 50% |
| Alexandra | Central Otago | 1,230 | 123,000 kWh | 41% |
| Dunedin | Coastal Otago | 1,230 | 123,000 kWh | 44% |
| Wānaka | Central Otago | 1,220 | 122,000 kWh | 40% |
| Cromwell | Central Otago | 1,200 | 120,000 kWh | 38% |
| Balclutha | Coastal Otago | 1,170 | 117,000 kWh | 50% |
| Gore | Southland | 1,140 | 114,000 kWh | 47% |
| Invercargill | Southland | 1,140 | 114,000 kWh | 45% |
| Greymouth | West Coast | 1,130 | 113,000 kWh | 52% |
| Hokitika | West Coast | 1,130 | 113,000 kWh | 52% |
| Queenstown | Central Otago | 1,120 | 112,000 kWh | 28% |
| Westport | West Coast | 1,090 | 109,000 kWh | 54% |
What it tells you
Reading the ranking
Blenheim leads, with Kaikōura, Christchurch and Nelson close behind. Solar yield is not quite the same as sunshine hours: it also depends on how high the sun climbs, cloud through the day and temperature, because panels lose a little output in heat.
Central Otago’s clear, dry summers put Alexandra, Wānaka and Cromwell mid-table. Their December output is among the highest in the table, but June falls to about 40 percent of December, and the ranges around Queenstown cut low winter sun further. That summer peak suits orchards, packhouses and wineries, whose refrigeration peaks at the same time.
Southland and the West Coast sit lowest, about 18 percent and 22 percent below Blenheim. Even so, a farm or factory there that uses most of its power in daylight can out-earn a poorly matched site in the sunniest town: load shape beats latitude, as the payback-by-industry table in commercial solar costs and payback shows. Winter holds up best in Nelson, where June still makes 58 percent of December, and worst in Queenstown, at 28 percent.
In our calculator
The regional figures we model with
| Region | kWh per kW a year | What 100 kW makes a year |
|---|---|---|
| Marlborough | 1,390 | 139,000 kWh |
| Nelson Tasman | 1,330 | 133,000 kWh |
| Canterbury | 1,310 | 131,000 kWh |
| Central Otago | 1,220 | 122,000 kWh |
| Coastal Otago | 1,220 | 122,000 kWh |
| Southland | 1,140 | 114,000 kWh |
| West Coast | 1,120 | 112,000 kWh |
Straight answers
Solar by town: questions
Where is the sunniest place in the South Island for solar?
Of the 21 towns we modelled, Blenheim has the highest solar yield, about 1,390 kWh per kW a year, followed by Kaikōura, Christchurch and Nelson. These are satellite-based yields for panels, not sunshine hours, and we did not model the North Island.
How much does a 100 kW solar system produce in New Zealand?
In the South Island, roughly 109,000 to 139,000 kWh a year depending on the town: about 134,000 kWh in Christchurch and 114,000 in Invercargill, for a north-facing system at the best tilt after a 10 percent allowance for real installs. Shading, roof angle and direction all change it.
Does solar work in Southland?
Yes. Invercargill and Gore make about 1,140 kWh per kW a year, about 18 percent less than Blenheim, and output peaks in the same summer months as dairy and processing loads. What decides the payback is how much of the generation you use on site, not the latitude.
Why does Queenstown make less solar power than Cromwell?
Mostly winter. The ranges around Queenstown cut off low winter sun, so its June output is about 28 percent of December's against 38 percent in Cromwell. In December the two towns make almost the same.
Where does this solar data come from?
PVGIS, the European Commission's free solar tool, using ERA5 climate data. We fetched each town on 2 October 2026 for a north-facing system at the best tilt, then took 10 percent off for real installs. The full table is free to download as CSV.
Know your town. Now model your site.
The calculator applies your region's yield to your own power bill: system size, cost, saving and payback in thirty seconds.