GreenlyFrost dates and when to plant in the Bay of Plenty
New Zealand
In the Bay of Plenty the last spring frost comes between 18 August (Tauranga) and 10 September (Rotorua) — the median of 2016–2025 in 2 cities. The first autumn frost comes around 26 May. That leaves about 258 days without frost. Tomato: plant out into open ground from 25 October in every city.
Frost dates by city in the Bay of Plenty
| City | Last spring frost | First autumn frost | Frost-free days | Climate zone | Tomato: window |
|---|---|---|---|---|---|
| Tauranga | 18 August | none in ten years | — | Frost without a regular season | from 25 October |
| Rotorua | 10 September | 26 May | 258 | 210–269 frost-free days | 26 November – 3 February |
Median of 2016–2025 for the 25 km grid cell of the city: the last day at or below 0 °C in spring and the first in autumn (ERA5 reanalysis via Open-Meteo). In a cold year a frost can come a week or two later — Greenly warns 48 hours ahead.
When to plant in the Bay of Plenty: windows by crop
The earliest start and the latest end among the cities here, each with its city; every city’s own window is on its page. Each window starts on the Greenly calendar date and ends on the last day that still leaves the crop’s days to harvest (from its card) before the average first autumn frost, plus six weeks of picking for crops harvested over weeks (tomatoes, peppers, aubergines, cucumbers, courgettes, pumpkins, watermelons, beans) — our rule; earlier in the window is safer.
| Crop | Planting out or sowing |
|---|---|
| Tomato | from 25 October (Tauranga) |
| Cucumber, Bell Pepper, Eggplant, Zucchini, Pumpkin, Watermelon | from 4 December (Tauranga) |
| Peas | from 28 July (Tauranga) |
| Garlic | Autumn planting: 26 April – end of June (Rotorua) |
| Tulip, Daffodil, Crocus, Hyacinth | Autumn planting: by 26 April (Rotorua) |
Weather by month in the Bay of Plenty
Across the 2 cities the warmest month is January (average days 22.7 … 23.5 °C) and the coldest August (average nights 3.8 … 6.7 °C). No city here averages below 0 °C at night in any month.
| Month | Day, °C | Night, °C | Rain, mm |
|---|---|---|---|
| January | 22.7 … 23.5 °C | 12.3 … 15.1 °C | 115 |
| February | 22.8 … 23.2 °C | 12.8 … 15.5 °C | 129 |
| March | 20.3 … 21.6 °C | 10.8 … 13.6 °C | 114 |
| April | 17.3 … 19.2 °C | 8.9 … 11.9 °C | 126 |
| May | 14.3 … 16.6 °C | 6.4 … 9.6 °C | 120 |
| June | 12.1 … 14.6 °C | 5 … 8.1 °C | 144 |
| July | 11.1 … 13.7 °C | 4 … 6.9 °C | 155 |
| August | 11.8 … 14.1 °C | 3.8 … 6.7 °C | 111 |
| September | 13.6 … 15.6 °C | 5.6 … 8.2 °C | 138 |
| October | 16.2 … 17.7 °C | 7.4 … 10 °C | 121 |
| November | 19 … 20 °C | 9.6 … 12.1 °C | 138 |
| December | 21.3 … 22.1 °C | 11.5 … 14 °C | 128 |
Day and night: the lowest … highest monthly average among the cities; rain: the middle city (ERA5 via Open-Meteo).
