Radicchio · Skokie, Illinois, United States
When to plant radicchio in Skokie
Main outdoor window
2-23 May
A climate estimate. Check your soil, forecast and cultivar.
Timed from last spring frost
4 April
In Skokie, on your chosen risk.
Ready to pick
1 Sep - 31 Dec
If you plant at the start of the window.
The average last frost. Half of all years are later than this.
Step by step in Skokie
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.
Sow direct
2-23 May
Four weeks after your last frost.
Harvest
1 Sep - 31 Dec
Radicchio through the year
Against the frost risk in Skokie
Seasonal context
Rainfall and the growing season in Skokie
May has the highest average precipitation (119 mm); January has the lowest (47 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.
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 Skokie
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 | -4.9°C (23.2°F)23.2°F (-4.9°C) | -0.2°C (31.7°F)31.7°F (-0.2°C) | 25.7 |
| February | -4.5°C (24°F)24°F (-4.5°C) | 0.8°C (33.5°F)33.5°F (0.8°C) | 23.6 |
| March | -0.5°C (31°F)31°F (-0.5°C) | 5.1°C (41.2°F)41.2°F (5.1°C) | 16.9 |
| April | 3.8°C (38.8°F)38.8°F (3.8°C) | 10°C (50°F)50°F (10°C) | 2.7 |
| May | 8.8°C (47.8°F)47.8°F (8.8°C) | 15.2°C (59.3°F)59.3°F (15.2°C) | 0.0 |
| June | 15.1°C (59.1°F)59.1°F (15.1°C) | 21.1°C (70°F)70°F (21.1°C) | 0.0 |
| July | 19.6°C (67.3°F)67.3°F (19.6°C) | 24.9°C (76.8°F)76.8°F (24.9°C) | 0.0 |
| August | 20°C (68.1°F)68.1°F (20°C) | 25.1°C (77.1°F)77.1°F (25.1°C) | 0.0 |
| September | 16.4°C (61.5°F)61.5°F (16.4°C) | 22°C (71.6°F)71.6°F (22°C) | 0.0 |
| October | 9.9°C (49.7°F)49.7°F (9.9°C) | 15.6°C (60°F)60°F (15.6°C) | 0.0 |
| November | 3.4°C (38.2°F)38.2°F (3.4°C) | 8.5°C (47.3°F)47.3°F (8.5°C) | 5.5 |
| December | -1.8°C (28.9°F)28.9°F (-1.8°C) | 2.7°C (36.8°F)36.8°F (2.7°C) | 18.4 |
For radicchio, also check drainage, sunlight and cultivar requirements. See the rainfall context above; humidity, irrigation and local pest pressure are not calculated.
Local growing check
Before choosing radicchio for Skokie
- May is the wettest month in the rainfall grid, averaging about 119 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 radicchio
Use the calendar to plan ahead, then check the conditions in your own garden.
- Measure the soil at sowing depth. Aim for at least 10°C (50°F); the calendar estimates soil warmth from air temperatures and cannot measure your bed.
- Frost tolerance does not make saturated or frozen soil suitable for planting. Wait until the bed can be worked without smearing or compacting it.
- 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.
Choose a head-forming radicchio for the right season
Provide a drained bed with steady moisture and spacing for the intended head. Cooler conditions and shorter days often help the red colour develop; a green young plant is not automatically the wrong seed.
Harvest firm usable heads before quality declines, removing damaged outer leaves. Some cut stumps may regrow, but treat that as a possible second harvest rather than a guarantee. Compare flavour raw and cooked before deciding that normal bitterness means crop failure.
What to record this season
Did the chosen sowing form a coloured head, and which harvest stage gave the best flavour? Add the cultivar, sowing date and conditions to your growing record so you can compare next season.
Further reading: RHS chicory growing guide . General crop guidance; local dates on this site are calculated separately. Source checked 19 September 2026 by Safe to Plant; this is not an expert review.
The RHS reference is written for UK growing conditions. Use its cultivation advice with local seasonal guidance; UK sowing months are not worldwide planting dates.
How the dates are calculated and their limits · Keep a growing record · Report a local discrepancy
Why these dates
Provide a drained bed with steady moisture and spacing for the intended head. Cooler conditions and shorter days often help the red colour develop; a green young plant is not automatically the wrong seed.
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.
This calendar uses frost-relative offsets as a starting point. Radicchio are timed for direct sowing 4 weeks after it, and this page simply resolves those offsets against the frost date computed for Skokie.
The calendar also applies a soil-warming estimate derived from historical air temperatures. Where that estimate is later than the frost-based date, it delays the window. Soil in your own garden can warm earlier or later; a thermometer at sowing depth is a better final check. Cold, wet conditions can slow germination and increase decay risk.
The median frost-free season here is 227 days, against 80 to 110 days to maturity for this crop counted from sowing. That margin is what decides whether a late sowing is worth attempting.
Also in Skokie
Other vegetables to time
Growing radicchio in Skokie
Can I grow radicchio in Skokie?
The calendar estimates a planting window, not a guarantee of success. May is the wettest month in the rainfall grid, averaging about 119 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 radicchio in Skokie?
Aim for 2-23 May in an average year. If you would rather not gamble on the weather, wait until 15 May - 5 Jun - by then frost has finished in nine years out of ten.
When might radicchio be ready to harvest in Skokie?
The estimated period is 1 Sep - 31 Dec, based on 80 to 110 days from the modeled planting date. Cultivar, planting material and growing conditions can change this interval; check the plant as well as the calendar.
How much frost will radicchio 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.