When to plant watermelons in Olympia: 26 June – 6 August

In Olympia, watermelon: sow for seedlings from 8 May to 9 July; plant into a greenhouse from 5 June to 6 August; plant out into open ground from 26 June to 6 August. For plants and seeds, the places nearby include Hefty Harvest (garden centre, 4 km) and Ladyberry Produce (farm shop, 12 km); addresses and opening hours are below.

Watermelon in Olympia: soil, season and weather

In Olympia the soil, not frost, sets the date: the last frost is over around 19 March, but the top 7 cm of soil reaches 18 °C — the minimum on the watermelon card — only around 26 June, 99 days later.

Last spring frost	19 March
Top 7 cm of soil at 18 °C	26 June, 99 days after the last frost
Into an unheated greenhouse	5 June – 6 August; June outside: 10.1 °C at night, 21.9 °C by day; card 18–35 °C
First autumn frost	15 November, 142 days after the start
Days in the bed to the first harvest (card)	59
First harvest, if planted in this window	24 August – 4 October
Days left for picking	83
Daylight	15:33 on 29 May, 15:53 on 26 June
Watering outdoors when fruiting (card)	every 5 days; the driest month, July, has 3 rainy days

The same dates in Olympia hold for Cucumber, Bell Pepper, Eggplant, Zucchini and Pumpkin.

Watermelon in Olympia: care after planting

Planted on 26 June: in the first weeks water every 5 days.

Feeding, by the card’s schedule from that day:

26 June — feed: balanced (NPK)

Pests and diseases of watermelon to watch for:

Dates count from the first planting day of the window above; a later planting moves them by as many days.

Weather in Olympia during the watermelon season

No month of the season averages above the watermelon card's 18–35 °C by day; the warmest, August, averages 26.7 °C. Months that stay below 18 °C even by day on average: October (15.4 °C) and November (10 °C). Nights average below 18 °C in every month of the season, from 4.5 °C to 13.5 °C.

Month	Day, °C	Night, °C	Rain, mm	Rainy days	Daylight on the 15th
June	21.9	10.1	54	8	15:53
July	26	12.3	11	3	15:33
August	26.7	13.5	25	4	14:16
September	22.2	11.5	70	9	12:37
October	15.4	7.5	147	14	10:57
November	10	4.5	206	18	9:23

ERA5 2016–2025, Open-Meteo

Watermelon in nearby cities

All the nearest cities on our list plant watermelon earlier than Olympia; the closest date is in Vancouver, 4 days earlier.

City	Distance	Date	Difference
Seattle	77 km	21 June – 15 August	5 days earlier
Victoria	159 km	13 June – 11 September	13 days earlier
Portland	170 km	17 June – 13 August	9 days earlier
Salem	234 km	6 June – 8 August	20 days earlier
Vancouver	250 km	22 June – 8 August	4 days earlier
Eugene	332 km	19 June – 20 July	7 days earlier

Where to buy watermelon plants and seeds near Olympia

Buy plants ready to set out from 26 June to 6 August (from 5 June to 6 August for an unheated greenhouse); seed for raising your own is sown from 8 May to 9 July. Within 15 km of Olympia OpenStreetMap lists 5 garden centres, 1 plant nursery, 2 markets and 2 farm shops (collected 28 October 2026).

Hefty Harvest — garden centre
Mon–Sun 10:00–18:00 · 4 km
Olympia Farmers Market — market
N Captiol Way 700, 98501 Olympia · Jan–Mar: Sat 10:00–15:00; Apr–Oct: Thu–Sun 10:00–15:00; Nov–Dec: Sat, Sun 10:00–15:00 · 1 km · olympiafarmersmarket.com
Ladyberry Produce — farm shop
Zangle Road Northeast 8038, 98506 Olympia · 12 km
Webster Forest Nursery — plant nursery
11 km

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.

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