GreenlyLast and first frost dates in San Jose
United States
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| Last spring frost | around 24 February |
|---|---|
| First autumn frost | none in ten years |
| Hardiness zone (USDA-equivalent) | official USDA map: 9b |
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 is the last frost in San Jose?
The last frost in San Jose usually comes around 24 February: that is the median of 2016–2025, so in about half of those years the last night at or below 0 °C came later. Hardy crops start before it and frost-tender ones only after it: in the table below arugula can go into open ground from 3 February, while corn waits until 3 March.
When to sow and plant
| Crop | Sow for seedlings | Plant out in a greenhouse | Open ground |
|---|---|---|---|
| Achocha | from 1 January | from 10 February | from 3 March |
| Ageratum | from 19 January | — | from 6 April |
| Arugula | — | — | sow from 3 February |
| Basil | from 25 February | from 4 April | from 25 April |
| Beet | — | — | sow from 3 February |
| Bell Pepper | from 3 February | from 4 April | from 25 April |
| Black-eyed Susan | from 10 December | — | from 3 March |
| Bok Choy | from 6 January | from 10 February | from 3 March |
| Borage | — | — | sow from 3 March |
| Broad bean | — | — | sow from 3 February |
| Broccoli | — | — | sow from 3 February |
| Brussels Sprouts | from 29 November | from 13 January | from 3 February |
| Busy Lizzie | from 9 December | — | from 3 March |
| Cabbage | — | — | sow from 3 February |
| Calendula | — | — | sow from 3 February |
| Carrot | — | — | sow from 3 February |
| Cauliflower | from 2 December | from 13 January | from 3 February |
| Celeriac | from 25 November | from 10 February | from 3 March |
| Celery | from 25 November | from 10 February | from 3 March |
| Celosia | from 13 February | from 30 March | from 20 April |
| Chamomile | — | — | sow from 3 February |
| Chayote | from 14 November | from 10 February | from 3 March |
| Chickpea | — | — | sow from 3 February |
| Chicory | from 19 December | — | from 3 February |
| Chili Pepper | from 3 February | from 4 April | from 25 April |
| China aster | from 11 February | from 4 April | from 25 April |
| Chives | — | — | sow from 3 February |
| Cilantro | — | — | sow from 3 February |
| Corn | — | — | sow from 3 March |
| Corn poppy | — | — | sow from 3 February |
| Cosmos | from 13 February | from 30 March | from 20 April |
| Cucumber | from 7 March | from 4 April | from 25 April |
| Daikon | — | — | sow from 3 February |
| Delphinium | from 15 November | — | from 3 February |
| Dill | — | — | sow from 3 February |
| Edging lobelia | from 9 December | — | from 3 March |
| Eggplant | from 3 February | from 4 April | from 25 April |
| Florence fennel | from 27 December | from 10 February | from 3 March |
| Foxglove | from 28 October | — | from 3 February |
| Garden sorrel | — | — | sow from 3 February |
| Green Beans | — | — | sow from 20 April |
| Hollyhock | — | — | sow from 3 February |
| Hyssop | — | — | sow from 3 February |
| Kale | — | — | sow from 3 February |
| Kiwano | from 12 February | from 16 March | from 6 April |
| Kohlrabi | — | — | sow from 3 February |
| Leek | from 4 November | from 13 January | from 3 February |
| Lemon balm | — | — | sow from 3 February |
| Lettuce | — | — | sow from 3 February |
| Lisianthus | from 18 October | from 13 January | from 3 February |
| Lovage | — | — | sow from 3 February |
| Luffa | from 21 February | from 4 April | from 25 April |
| Marigold | from 30 December | from 10 February | from 3 March |
| Marjoram | from 3 February | — | from 25 April |
| Melon | from 7 March | from 4 April | from 25 April |
| Microgreens | — | — | sow from 20 April |
| Moringa | from 17 February | from 13 April | from 4 May |
| Moss rose | from 16 December | — | from 3 March |
| Mustard greens | — | — | sow from 3 February |
| Napa cabbage | from 8 January | from 10 February | from 3 March |
| Nasturtium | from 3 January | from 10 February | from 3 March |
| Okra | from 21 February | from 4 April | from 25 April |
| Oregano | from 14 November | from 13 January | from 3 February |
| Pansy | from 18 November | from 13 January | from 3 February |
| Parsley | — | — | sow from 3 February |
| Parsnip | — | — | sow from 3 February |
| Peanut | from 26 February | from 4 April | from 25 April |
| Peas | — | — | sow from 3 February |
| Petunia | from 31 January | from 4 April | from 25 April |
| Physalis | from 30 January | from 16 March | from 6 April |
| Pumpkin | from 21 February | from 4 April | from 25 April |
| Purple coneflower | from 12 November | — | from 3 February |
| Radish | — | — | sow from 3 February |
| Sage | from 25 November | from 13 January | from 3 February |
| Scarlet sage | from 23 January | — | from 6 April |
| Snapdragon | from 9 November | from 13 January | from 3 February |
| Soybean | — | — | sow from 25 April |
| Spinach | — | — | sow from 3 February |
| Stevia | from 26 January | from 16 March | from 6 April |
| Stock | — | — | sow from 3 February |
| Sunflower | — | — | sow from 20 April |
| Sweet alyssum | — | — | sow from 3 February |
| Sweet Corn | from 25 January | from 16 February | from 9 March |
| Sweet pea | from 2 December | from 13 January | from 3 February |
| Sweet William | — | — | sow from 3 February |
| Swiss Chard | — | — | sow from 3 February |
| Thyme | — | — | sow from 3 February |
| Tomato | from 23 January | from 16 March | from 6 April |
| Turnip | — | — | sow from 3 February |
| Watercress | — | — | sow from 3 February |
| Watermelon | from 7 March | from 4 April | from 25 April |
| Zinnia | from 9 March | from 13 April | from 4 May |
| Zucchini | from 14 March | from 4 April | from 25 April |
Planting out: a week after the last frost once the soil is warm enough for the crop; frost-hardy crops three weeks before it; an unheated greenhouse three weeks earlier. Seedlings are sown so they are ready on that day. 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.
What planting zone is San Jose?
The official USDA map (2023, 1991–2020 data) puts the centre of San Jose (ZIP 95113) in zone 9b. Zone 9b stands for an average coldest night of 25 to 30 °F (-3.9 to -1.1 °C), so perennials hardy to zone 9b or a colder zone should come through a typical winter here.
Check the official USDA map for San Jose: USDA Plant Hardiness Zone Map.
When the soil warms up in San Jose
The day the top 7 cm of soil first averages each temperature over a week, median of 2016–2025 (ERA5 via Open-Meteo). The soil reaches 10 °C 42 days before the last spring frost and 15 °C 41 days after it.
| Soil | Date | Against the last spring frost |
|---|---|---|
| 5 °C | already in the first week of January | — |
| 10 °C | 13 January | 42 days earlier |
| 15 °C | 6 April | 41 days later |
| 18 °C | 25 April | 60 days later |
Frost dates near San Jose
Of the nearest cities on our list, the last spring frost ends earliest in Stockton (4 February) and latest in Carson City (1 May).
| City | Distance | Last spring frost | First autumn frost |
|---|---|---|---|
| San Francisco | 67 km | — | — |
| Stockton | 87 km | 4 February | 3 December |
| Sacramento | 142 km | 18 February | 11 December |
| Fresno | 199 km | 5 February | 5 December |
| Carson City | 274 km | 1 May | 22 October |
Seeds, seedlings and markets in San Jose
Within 15 km of San Jose OpenStreetMap lists 11 garden centres, 1 farm-supply shop, 1 plant nursery, 16 markets and 1 farm shop (collected 20 October 2026). The nearest garden centre to the city centre is Plant Sitter, 2 km away.
- Plant Sitter — garden centre
South 1st Street 605, 95113 San Jose · 12:00–17:30 · 2 km · theplantsitter-california.square.site - Sunny Tools — farm supply
Parrott Street 580, 95112 San Jose · 5 km - Central Wholesale Nursery — plant nursery
McKinley Avenue 1670, 95126 San Jose · Mon–Fri 07:30–16:30; Sat 07:00–15:00 · 5 km - Downtown San Jose Farmers’ Market — market
Fri 10:00–14:00 · 1 km - SCUSD Farmstand — farm shop
Dunford Way 1055, 94087 Sunnyvale · 10 km - Bay Maples — garden centre
North 1st Street 1231, 95112 San Jose · Mon–Thu 07:00–17:30 · 3 km · baymaples.com
Places: © OpenStreetMap contributors, ODbL.
San Jose: weather for the next 7 days
Forecast by Open-Meteo. Nights at or below 0 °C are marked as frost.
Weather in San Jose by month
Average weather in San Jose over 2016–2025: the warmest month is July. Months that average 20 °C or more by day: April–October (20.8–30.2 °C). Months that average 30 °C or more by day: July (30.2 °C) and August (30.1 °C). No month averages below 0 °C at night; the coldest nights, in February, average 6.1 °C. About 556 mm of rain falls in a year, on 56 days; January is the wettest month (121 mm) and June the driest (0 mm).
| Month | Day, °C | Night, °C | Rain, mm | Rainy days |
|---|---|---|---|---|
| January | 14.5 | 6.2 | 121 | 10 |
| February | 16 | 6.1 | 89 | 8 |
| March | 16.9 | 7 | 99 | 11 |
| April | 20.8 | 8.6 | 27 | 4 |
| May | 24.4 | 10.8 | 16 | 3 |
| June | 28.7 | 13.3 | 0 | 0 |
| July | 30.2 | 14.5 | 0 | 0 |
| August | 30.1 | 15 | 1 | 0 |
| September | 28.7 | 14.5 | 5 | 1 |
| October | 24.7 | 12.2 | 34 | 3 |
| November | 18.2 | 8.6 | 54 | 6 |
| December | 14.5 | 6.6 | 110 | 10 |
Average of the daily highs and lows, rain per month and days with at least 1 mm (ERA5 via Open-Meteo, the same grid cell as the frost dates).
