Source
https://niwa.co.nz/climate-and-weather/climate-data/national-climate-database/climate-station-normals — original source (opens in a new tab; the file is not redistributed)
NIWA — Regional Climate Normals 1991–2020
The national climate-by-region layer for the water + food slices — resolves RT_142
NIWA’s official climate-station normals (1991–2020 means, locations with ≥5 complete years): annual rainfall (30 locations), mean air temperature (31), and ground-frost days (22), per NZ location. Supplies the regional
rainfall_mmcolumn the water slice needs to extend nationally beyond the Tasman pilot, plus the temperature/frost layer for the future food/frost refinement. Official NIWA normals → data_quality: verified.
Summary
Three NIWA climate-station normals tables (1991–2020 means), downloaded from NIWA’s climate pages: mean monthly + annual rainfall (mm), mean monthly + annual air temperature (°C), and mean annual ground-frost days. Each lists 22–31 NZ locations spanning every region. This is the national climate-by-region layer that decision National scope (2026-05-31) and RT_142 call for — extending the pilot’s Nelson/Tasman figures to a per-region table the water (rainfall_mm) and future food/frost layers consume.
Key claims
- claim: "Mean annual rainfall (mm/yr, NIWA 1991–2020 normals) by region (main centre): Northland (Whangārei) 1,289; Auckland 1,119; Waikato (Hamilton) 1,124; Bay of Plenty (Tauranga) 1,202; Gisborne 1,001; Hawke's Bay (Napier) 790; Taranaki (New Plymouth) 1,410; Manawatū-Whanganui (Palmerston North) 984; Wellington 1,319; Tasman/Nelson (Nelson) 976; Marlborough (Blenheim) 639; West Coast (Hokitika) 2,921; Canterbury (Christchurch) 618; Otago (Dunedin) 724; Southland (Invercargill) 1,097; Chatham Islands 837. Driest = Canterbury + Marlborough (~620–640); wettest = West Coast (Hokitika 2,921; Milford Sound 6,545). Pilot Nelson 976 mm is consistent with OT_030."
source_location: "rainfall_1991-2020.xlsx, 'Data' sheet, YEAR column"
- claim: "Mean annual air temperature (°C, NIWA 1991–2020) by main centre: Auckland 15.6, Tauranga 15.1, Gisborne 15.1, Napier 14.7, Hamilton 13.9, New Plymouth 13.8, Palmerston North 13.4, Blenheim 13.2, Wellington 13.1, Nelson 13.1, Chatham Is 12.2, Hokitika 11.9, Christchurch 11.6, Dunedin 11.2, Invercargill 10.1; coldest inland Lake Tekapo 9.0. A ~6.6 °C north–south/altitude gradient (Auckland → Tekapo)."
source_location: "mean-air-temperature_1991-2020.xlsx, 'Data' sheet, YEAR column"
- claim: "Mean annual GROUND-frost days (grass-level frost, far more frequent than air frost; NIWA 1991–2020): low in the warm north — Wellington 3.1, Auckland 4.2, New Plymouth 8.4 — rising sharply inland and south — Napier 18.8, Gisborne 32.1, Hokitika 34.9, Palmerston North 41.4, Hamilton 45.5, Blenheim 47.8, Dunedin 49.8, Invercargill 66.8, Nelson 74.9, Christchurch 84.8, Alexandra 116.6, Queenstown 116.8, Lake Tekapo 158.0. Frost data available for 22 of the 30 locations."
source_location: "ground-frost-days_1991-2020.xlsx, 'Data' sheet, YEAR column"Neobiome Intelligence relevance
Resolves RT_142 — the national climate-by-region layer. Its load-bearing use is the water slice: rainwater = rainfall_mm × runoff (0.8) × roof area, so this populates the regional rainfall_mm column that lets the water SSI run for any NZ region, not just Tasman. The regional spread is large and design-relevant: rainwater-harvest potential varies ~4.7× across regions — a West Coast community (Hokitika 2,921 mm) harvests nearly five times what a Canterbury (Christchurch 618 mm) or Marlborough (Blenheim 639 mm) community does from the same roof, so water SSI in the dry east will be materially lower than the Tasman pilot’s ≈0.66 (Nelson 976 mm). The temperature and ground-frost layers feed the future food/frost refinement (growing-season length, crop selection, and a frost-risk/P90 dry-year companion per the model’s D16 bands) — e.g. the pilot’s Nelson ~75 ground-frost days/yr is a real constraint on year-round outdoor cropping. Pilot figures (Nelson 976 mm, 13.1 °C) corroborate OT_030 (Macara 2016). ⚠ Single-station-per-region is a simplification — within-region rainfall varies enormously (the West Coast vs Canterbury contrast exists within the South Island over ~100 km); for a specific site, a NIWA SolarView/CliFlo point run (RT_099) remains the finer step.
Research targets
Research gaps
- RT_142 (RESOLVED → this page): national per-region rainfall + mean temperature + ground-frost normals now held; populates the water slice’s regional
rainfall_mmand the future food/frost layer.
Connections
Referenced by
Sources (6): LIT_077 · OT_164 · OT_168 · OT_182 · RD_023 · RD_033
Decisions (1): D_002: National scope — all of NZ, no single p…
EDT domains (1): D02: Smart Food Systems & Agriculture
Concepts (1): Self-Sufficiency Calculation Framework