Last and first frost dates in Riverside

When is the last frost in Riverside?

The last frost in Riverside usually comes around 12 January: 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 22 December, while corn waits until 19 January. The first autumn frost follows around 19 December, about 341 days later: harvest or cover frost-tender crops before then.

When to sow and plant

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.

When the soil warms up in Riverside

The day the top 7 cm of soil first averages each temperature over a week, median of 2016–2025 (ERA5 via Open-Meteo).

Frost dates near Riverside

Of the nearest cities on our list, the last spring frost ends earliest in Bakersfield (16 February) and latest in Santa Barbara (15 March).

Seeds, seedlings and markets in Riverside

Within 15 km of Riverside OpenStreetMap lists 4 garden centres, 30 plant nurseries, 7 markets and 10 farm shops (collected 28 October 2026). The nearest garden centre to the city centre is Milfelds Nursery, 4 km away.

• Milfelds Nursery — garden centre
  Adams Street 2550, 92504 Riverside · Mon–Fri 07:00–15:30 · 4 km · milfeldsnursery.com
• Olympic Market — market
  Cridge Street 3072, 92507 Riverside · 3 km
• Walmart Garden Center — garden centre
  North McKinley Street 479, 92879 Corona · Mon–Sun 06:00–24:00 · 13 km · walmart.com
• Victoria Grove Produce Market — market
  Blackburn Road 12261, 92503 Riverside · sunrise–sunset · 11 km
• Lake Mathews Market — market
  Cajalco Road 17679, 92570 Perris · Mon–Sat 07:00–18:30 · 14 km

• Where to buy seeds and seedlings in Riverside
• Selling your own harvest in the United States

Places: © OpenStreetMap contributors, ODbL.

Weather in Riverside by month

Average weather in Riverside over 2016–2025: the warmest month is August. Months that average 20 °C or more by day: February–December (20.3–35.7 °C). Months that average 30 °C or more by day: June–September (31.9–35.7 °C). No month averages below 0 °C at night; the coldest nights, in January, average 7.4 °C. About 386 mm of rain falls in a year, on 41 days; January is the wettest month (85 mm) and June the driest (1 mm).

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).

Planted in autumn

From a month before the first autumn frost, so the roots grow before winter, to the late-planting limit on each crop’s page (about two weeks before the ground freezes, by ten years of weather).