When to plant pumpkin in Riverside

In Riverside, typical last spring frost is February 5 and typical first fall frost is December 19. Typical last spring frost: February 5. Pumpkin in Riverside is a good fit outdoors. The suitable growing window of 141 days covers the 90–120 days this plant usually needs.

Pumpkin

How to grow Pumpkin Riverside climate Weekly temperatures and windows

Where are you growing?

Comfortable

Comfortable in greenhouse

Comfortable in a cold frame

Pumpkin in Riverside is a good fit outdoors. The suitable growing window of 141 days covers the 90–120 days this plant usually needs.

When to plantMay 9 – July 3

Harvest: August 7 – October 31
Season vs crop: 141 grow days vs 90–120 needed
Typical frost (last spring – first fall): February 5 – December 19

Pumpkin in Riverside is a good fit outdoors. The suitable growing window of 141 days covers the 90–120 days this plant usually needs.

Planting conditions

Direct sow
Grow outdoors
Harvest

Local activity windows for this place and growing method. Blue fill is usually too cold for this plant. Dashed lines are typical last and first frost.

Suitable growing days in a row141

Days to harvest90–120 days from seed

May 9 – Jul 3

Direct sow

Jul 4 – Aug 6

Grow outdoors

Aug 7 – Oct 31

Harvest

Activity	Window	Notes
Direct sow	May 9 – Jul 3	Plant outdoors in this window.
Grow outdoors	Jul 4 – Aug 6	Plants grow outdoors until harvest.
Harvest	Aug 7 – Oct 31	Expected harvest from typical days to harvest.

Direct sow
Grow outdoors
Harvest

Blue fill is usually too cold for this plant. Dashed lines are typical last and first frost (35 seasons (1991–2025)). Adjust a week or two for your conditions.

Planting and growing across the year

Planting is the sow / plant-out window. Growing is daytime air versus this plant’s ideal (21 – 35 °C70 – 95 °F21 – 35 °C (70 – 95 °F)) and tolerable (16 – 38 °C61 – 100 °F16 – 38 °C (61 – 100 °F)) ranges.

Ideal / plantable
Tolerable
Too cold
Too hot
Outside window

Planting uses sow / plant-out rules; growing shows daytime air against this plant’s ideal and tolerable ranges.

Key dates

Typical last spring frostFebruary 5

Low-risk last spring frostFebruary 28

Typical first fall frostDecember 19

Low-risk first fall frostNovember 30

Frost-free days316

Outdoor sow dateMay 9

Direct sow windowMay 9 – July 3

Suitable growing windowMay 9 – September 26 (141 days)

Expected harvestAugust 7 – October 31

How these dates are judged

Ideal conditions: Daytime air from 21 – 35 °C70 – 95 °F21 – 35 °C (70 – 95 °F).
Suitable conditions: Daytime air from 16 – 38 °C61 – 100 °F16 – 38 °C (61 – 100 °F).
Last frost and first frost: Typical spring and fall frost dates for Riverside, shown in the key dates.
Days to harvest: 90–120 days from seed, from typical days to harvest.
Sowing window: Dated sow and harvest bars use frost dates, soil minima, night limits, and last-sow count-back from typical crop timing. Air ratings on the weekly chart colour only weeks inside that same window — see weekly temperatures and windows.

Other plants for Riverside

Calculated by Plan & Plant. Method. Data 35 seasons (1991–2025).

Frost and suitability dates are typical figures from climate statistics.

Based on 35 years (1991–2025) of ERA5-Land data from Open-Meteo, for an area of about 10 km. Typical dates, not a guarantee.

Dates for Riverside use ERA5-Land cell 33.95, -117.40. How we calculated this · Algorithm 2026-10-season-10.

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