Toronto in December: what to plant

Averaged over the last 5 years of daily records, December in Toronto runs -2.8–3.1°C with about 86 mm of rain across the month. Here is what that climate actually supports.

❄️ In 5 of the last 5 years, Toronto saw at least one night at or below 0°C in December (record low -17.0°C). Cold-sensitive crops need cover.

Best crops to sow now

1. 🌱 Microgreens Fastest about 8 days to harvest 🪴 Windowsill pot — sheltered from outdoor weather
2. 🍃 Mint about 30 days to harvest 🪴 Windowsill pot — sheltered from outdoor weather
3. 🧅 Chives about 32 days to harvest 🪴 Windowsill pot — sheltered from outdoor weather
4. 🌿 Basil about 34 days to harvest 🪴 Windowsill pot — sheltered from outdoor weather

Leave these for another month

• 🏵️ Marigold — Recent mean 0.1°C is too cold (ideal 12–30°C)
• 🌻 Sunflower — Recent mean 0.1°C is too cold (ideal 14–30°C)
• 🧅 Onion — Recent mean 0.1°C is too cold (ideal 8–28°C)

Other months in Toronto

• January
• February
• March
• April
• May
• June
• July
• August
• September
• October
• November
• December

Temperature and rainfall are 5-year daily normals from the ERA5 reanalysis via Open-Meteo. Suitability is scored with the same degree-day model the game runs on — it is not a generic planting calendar.