When to plant watermelons in Rivera: 28 September – 29 February

In Rivera, watermelon: sow for seedlings from 10 August to 1 February; plant into a greenhouse from 7 September to 29 February; plant out into open ground from 28 September to 29 February.

Watermelon in Rivera: soil, season and weather

In Rivera the soil, not frost, sets the date: the last frost is over around 30 July, but the top 7 cm of soil reaches 18 °C — the minimum on the watermelon card — only around 28 September, 60 days later.

Last spring frost	30 July
Top 7 cm of soil at 18 °C	28 September, 60 days after the last frost
Into an unheated greenhouse	7 September – 29 February; September outside: 10.9 °C at night, 20.5 °C by day; card 18–35 °C
First autumn frost	9 June, 255 days after the start
Days in the bed to the first harvest (card)	59
First harvest, if planted in this window	26 November – 28 April
Days left for picking	196
Daylight	11:26 on 31 August, 12:17 on 28 September
Watering outdoors when fruiting (card)	every 5 days; the driest month, December, has 8 rainy days

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

Watermelon in Rivera: care after planting

Planted on 28 September: in the first weeks water every 5 days.

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

28 September — 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 Rivera during the watermelon season

No month of the season averages above the watermelon card's 18–35 °C by day; the warmest, January, averages 29.6 °C. Months that stay below 18 °C even by day on average: June (17.1 °C). Nights average below 18 °C in March–June and September–December (8.8–17.6 °C).

Month	Day, °C	Night, °C	Rain, mm	Rainy days	Daylight on the 15th
September	20.5	10.9	178	10	11:53
October	23.1	12.8	135	10	12:48
November	26.3	15.1	104	8	13:40
December	28.7	17.6	101	8	14:08
January	29.6	19.4	131	10	13:56
February	29.3	19.1	102	9	13:10
March	27.1	17.3	109	9	12:19
April	23.6	14.6	114	9	11:21
May	19	10.9	132	10	10:34
June	17.1	8.8	101	8	10:09

ERA5 2016–2025, Open-Meteo

Watermelon in nearby cities

Around Rivera, Posadas is 65 days earlier and Tacuarembó 16 days later.

City	Distance	Date	Difference
Tacuarembó	99 km	14 October – 4 March	16 days later
Santa Maria	214 km	14 August – 3 March	45 days earlier
Salto	236 km	from 22 August	37 days earlier
Paysandú	288 km	21 September – 17 March	7 days earlier
Posadas	392 km	from 25 July	65 days earlier
Passo Fundo	422 km	8 September – 8 March	20 days earlier

Where to buy watermelon plants and seeds near Rivera

Buy plants ready to set out from 28 September to 29 February (from 7 September to 29 February for an unheated greenhouse); seed for raising your own is sown from 10 August to 1 February. Within 15 km of Rivera OpenStreetMap lists 2 markets (collected 28 October 2026).

Camelódromo — market
1 km
Feira Cabotiá — market
2 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.

Questions