Watermelon · Diadema, São Paulo, Brazil
When to plant watermelons in Diadema
Main outdoor window
1 Oct - 15 Nov
A climate estimate. Check your soil, forecast and cultivar.
Timed from temperature
October to March
No frost on record in Diadema, so the months this crop fits in our temperature model set the timing. This does not confirm local suitability.
First autumn frost
no autumn frost
The far end of the outdoor season.
Temperature-based estimate. Diadema has no dependable frost season.
These dates do not account for rain, humidity or waterlogging. Check the local growing season,
especially in monsoon climates, before treating this window as a planting recommendation.
Rainfall check: the wettest month is January (about 230 mm), and the driest is
August (about 36 mm).
Compare all months and check the limitations before choosing the season.
Step by step in Diadema
Download these planting dates (.ics)
Import into Apple Calendar, Google Calendar or Outlook. Dates use the selected risk level and are planning estimates, not frost alerts.
Each window is a planning range. Check the forecast, soil and cultivar before planting; a later date is not automatically safer in hot or wet conditions.
Plant out
1 Oct - 15 Nov
The opening weeks of the stretch when the average temperature suits this crop, which here runs from October to March. There is no frost to work around, so heat is what sets the timing.
Watermelons through the year
Against the monthly temperature record in Diadema
Seasonal context
Rainfall and the growing season in Diadema
January has the highest average precipitation (230 mm); August has the lowest (36 mm). Compare this pattern with the planting windows and your water supply.
During wetter months, check that beds and containers drain after heavy rain. During drier months, plan how you will keep seeds and new transplants watered. Monthly averages can hide long dry spells and intense storms; they do not show soil moisture, humidity or this week's weather.
Frost-free does not mean every month is suitable. In tropical and monsoon climates, rainfall, heat, drainage and the cultivar can set the practical growing season. Match the temperature window to these conditions and check advice from a local grower before buying planting material.
Source: NASA POWER, corrected MERRA-2 precipitation, 2001–2020. Values are approximate monthly totals, including the water equivalent of snow, from the nearest 0.5° × 0.625° grid cell. This reference period differs from the temperature record. Rainfall provides context and does not change the calculated planting dates. Method and limitations.
Monthly growing conditions in Diadema
Compare the planting window with the local temperature pattern. These are historical monthly averages, not this year's forecast or measured soil temperatures. Average frost days do not tell you whether a particular night will freeze.
| Month | Average low | Average high | Frost days |
|---|---|---|---|
| January | 18.6°C (65.5°F)65.5°F (18.6°C) | 27.1°C (80.9°F)80.9°F (27.1°C) | 0.0 |
| February | 18.5°C (65.3°F)65.3°F (18.5°C) | 27.3°C (81.1°F)81.1°F (27.3°C) | 0.0 |
| March | 17.9°C (64.2°F)64.2°F (17.9°C) | 26.5°C (79.8°F)79.8°F (26.5°C) | 0.0 |
| April | 15.8°C (60.5°F)60.5°F (15.8°C) | 25.3°C (77.5°F)77.5°F (25.3°C) | 0.0 |
| May | 12.8°C (55.1°F)55.1°F (12.8°C) | 22.7°C (72.8°F)72.8°F (22.7°C) | 0.0 |
| June | 11.7°C (53°F)53°F (11.7°C) | 22.1°C (71.8°F)71.8°F (22.1°C) | 0.0 |
| July | 11°C (51.8°F)51.8°F (11°C) | 22.4°C (72.3°F)72.3°F (22.4°C) | 0.0 |
| August | 11.8°C (53.3°F)53.3°F (11.8°C) | 24.5°C (76°F)76°F (24.5°C) | 0.0 |
| September | 13.7°C (56.7°F)56.7°F (13.7°C) | 26.7°C (80°F)80°F (26.7°C) | 0.0 |
| October | 15.4°C (59.7°F)59.7°F (15.4°C) | 27.4°C (81.4°F)81.4°F (27.4°C) | 0.0 |
| November | 16°C (60.9°F)60.9°F (16°C) | 27.1°C (80.7°F)80.7°F (27.1°C) | 0.0 |
| December | 17.7°C (63.8°F)63.8°F (17.7°C) | 27.6°C (81.7°F)81.7°F (27.6°C) | 0.0 |
For watermelons, also check drainage, sunlight and cultivar requirements. See the rainfall context above; humidity, irrigation and local pest pressure are not calculated.
The catalog flowering or harvest months are not verified for this frost-free climate. Ask a local grower about the cultivar’s seasonal cycle.
Local growing check
Before choosing watermelons for Diadema
- January is the wettest month in the rainfall grid, averaging about 230 mm. Check how your own bed drains and plan watering around actual soil moisture; monthly rain totals are not an irrigation schedule.
The temperature and rainfall tables on this page show the underlying climate estimates. How these suitability checks work · Record what happens in your garden.
Before you plant watermelons
Use the calendar to plan ahead, then check the conditions in your own garden.
- Measure the soil at sowing depth. Aim for at least 21°C (69.8°F); the calendar estimates soil warmth from air temperatures and cannot measure your bed.
- In a frost-free climate, check seasonal rainfall, humidity and heat before planting. A month with suitable average temperatures can still be too wet, dry or hot for this crop.
- Harden off plants raised indoors: gradually expose them to outdoor light, wind and temperature before their final move into the bed.
- Use the maturity range on your seed packet when choosing a variety. Cold, short days and transplant stress can make harvest later than the calendar estimate.
Warmth, space and successful pollination
Check the mature vine size before allocating space. Even small-fruited varieties are not necessarily small plants, and the fruit’s eventual weight matters if growing vertically.
Keep soil moist but not waterlogged. Heat stress, excessive water and poor pollination can all reduce fruit set, so healthy leaves do not by themselves promise a crop.
Cold rainy weather can interfere with pollination. Inspect flowers and developing fruit, and use the variety’s ripeness indicators before harvesting; immature fruit will not gain sweetness merely by being picked.
Further reading: NC State Extension Plant Toolbox: watermelon . General crop guidance; local dates on this site are calculated separately. Source checked 18 September 2026 by Safe to Plant; this is not an expert review.
How the dates are calculated and their limits · Keep a growing record · Report a local discrepancy
Why these dates
Frost-relative timing needs a dependable seasonal frost date. Diadema has no such date in this record, so this page compares monthly temperatures with the crop's model range instead. Local wet and dry seasons, day length and cultivar requirements still need a separate check.
The model uses a growing-temperature band for watermelons between 21°C (69.8°F)69.8°F (21°C) and 32°C (89.6°F)89.6°F (32°C) — and in Diadema that is October to March, 6 months of the year, taken from this location's own monthly averages. The planting window begins near the start of this period.
Nearby
Watermelons in places close by
Also in Diadema
Other vegetables to time
Growing watermelons in Diadema
Can I grow watermelons in Diadema?
The calendar estimates a planting window, not a guarantee of success. January is the wettest month in the rainfall grid, averaging about 230 mm. Check how your own bed drains and plan watering around actual soil moisture; monthly rain totals are not an irrigation schedule.
When should I plant watermelons in Diadema?
The temperature-based window is 1 Oct - 15 Nov. Diadema has no dependable frost season: October to March have monthly averages inside the model range for watermelons. Check seasonal rainfall, heat and cultivar requirements before planting.
How much frost will watermelons tolerate?
Check the named variety and local forecast before exposing young growth. The catalog cold-damage figure is a reference, not a guarantee: plant age, acclimatisation, wind and the duration of a freeze affect damage.