Last and first frost dates in Mercedes

When is the last frost in Mercedes?

The last frost in Mercedes usually comes around 14 July: 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 23 June, while corn waits until 21 July. The first autumn frost follows around 16 June, about 337 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 Mercedes

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 Mercedes

Of the nearest cities on our list, the last spring frost ends earliest in Colonia del Sacramento (9 July) and latest in La Plata (30 July).

Weather in Mercedes by month

Average weather in Mercedes over 2016–2025: the warmest month is January. Months that average 20 °C or more by day: September–April (20.3–30.8 °C). Months that average 30 °C or more by day: January (30.8 °C). No month averages below 0 °C at night; the coldest nights, in July, average 7.5 °C. About 1089 mm of rain falls in a year, on 90 days; April is the wettest month (122 mm) and June the driest (69 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).