When to plant watermelons in Guarda: 28 May – 16 August

In Guarda, watermelon: sow for seedlings from 9 April to 19 July; plant into a greenhouse from 7 May to 16 August; plant out into open ground from 28 May to 16 August.

Watermelon in Guarda: soil, season and weather

In Guarda the soil, not frost, sets the date: the last frost is over around 2 April, but the top 7 cm of soil reaches 18 °C — the minimum on the watermelon card — only around 28 May, 56 days later.

Last spring frost	2 April
Top 7 cm of soil at 18 °C	28 May, 56 days after the last frost
Into an unheated greenhouse	7 May – 16 August; May outside: 8.2 °C at night, 18.8 °C by day; card 18–35 °C
First autumn frost	25 November, 181 days after the start
Days in the bed to the first harvest (card)	59
First harvest, if planted in this window	26 July – 14 October
Days left for picking	122
Daylight	13:53 on 30 April, 14:47 on 28 May
Watering outdoors when fruiting (card)	every 5 days; the driest month, August, has 1 rainy day

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

Watermelon in Guarda: care after planting

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

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

28 May — 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 Guarda during the watermelon season

No month of the season averages above the watermelon card's 18–35 °C by day; the warmest, August, averages 28.4 °C. Months that stay below 18 °C even by day on average: November (11.3 °C). Nights average below 18 °C in every month of the season, from 4.6 °C to 14.9 °C.

Month	Day, °C	Night, °C	Rain, mm	Rainy days	Daylight on the 15th
May	18.8	8.2	51	8	14:25
June	23	11.8	43	8	15:03
July	27.8	14.5	6	2	14:48
August	28.4	14.9	4	1	13:49
September	22.8	11.7	39	6	12:30
October	18.2	9.4	109	11	11:11
November	11.3	4.6	100	12	9:57

ERA5 2016–2025, Open-Meteo

Watermelon in nearby cities

All the nearest cities on our list plant watermelon earlier than Guarda; the closest date is in Viseu, 1 day earlier.

City	Distance	Date	Difference
Viseu	56 km	27 May – 31 August	1 day earlier
Castelo Branco	82 km	30 April – 16 September	28 days earlier
Vila Real	93 km	18 May – 12 September	10 days earlier
Coimbra	105 km	from 12 May	16 days earlier
Plasencia	115 km	8 May – 20 September	20 days earlier
Porto	132 km	22 May – 9 September	6 days earlier

Where to buy watermelon plants and seeds near Guarda

Buy plants ready to set out from 28 May to 16 August (from 7 May to 16 August for an unheated greenhouse); seed for raising your own is sown from 9 April to 19 July. Within 15 km of Guarda OpenStreetMap lists 2 markets (collected 27 October 2026).

Mercado Municipal da Guarda — market
1 km
Mercado Municipal de S. Miguel da Guarda — market
3 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