Frost dates in Quebec City: last spring frost and first autumn frost
When is it safe to plant out in Quebec City, and when does the first frost come? Dates from 45 years of nightly minimum temperatures (1981–2025), with how early or late they can fall.
Frost dates in Quebec City and how sure they are
| Early year (1 in 10) | Typical (median) | Late year (1 in 10) | |
|---|---|---|---|
| Last spring frost | 27 April | 9 May | 23 May |
| First autumn frost | 1 October | 13 October | 30 October |
In a typical year the last frost in Quebec City falls around 9 May and the first one around 13 October, leaving about 157 frost-free days (between 140 and 175 in 8 years out of 10). To be safe, plant tender crops after 23 May: by then the last frost has passed in 9 years out of 10. Bring them in before 1 October: in 1 year in 10 the first frost comes earlier.
Frost month by month in Quebec City
| Month | Average low | Coldest night (avg) | Record low | Frost nights | Years with frost |
|---|---|---|---|---|---|
| January | -18.2 °C | -30.9 °C | -43.6 °C | 30.8 | 100% |
| February | -16.7 °C | -29 °C | -36.5 °C | 27.6 | 100% |
| March | -10.5 °C | -23.9 °C | -32.5 °C | 29.4 | 100% |
| April | -1.5 °C | -9.7 °C | -18.7 °C | 18.1 | 100% |
| May | 5.7 °C | -0.9 °C | -2.9 °C | 2.3 | 78% |
| June | 11.6 °C | 5.2 °C | 0 °C | 0 | 0% |
| July | 14.8 °C | 9.6 °C | 6.2 °C | 0 | 0% |
| August | 13.9 °C | 8.2 °C | 3.9 °C | 0 | 0% |
| September | 9.5 °C | 3 °C | -1.3 °C | 0.1 | 9% |
| October | 3.5 °C | -2.7 °C | -6.5 °C | 7 | 93% |
| November | -3.6 °C | -13.1 °C | -20.5 °C | 22.8 | 100% |
| December | -12.8 °C | -25.3 °C | -36 °C | 30.2 | 100% |
Frost here means a night minimum at or below 0 °C at 2 m. Frost nights is the average count per month; years with frost is how many years had at least one.
Frost alerts for your garden or field
LayEarth Business Agro sends an alert when the forecast low at your saved site drops below your threshold (0 °C by default), with frost risk, hours below zero and white or black frost for each forecast day. LayEarth Pro, from 9 USD a month, adds alerts for the places you follow.
Temperature map around Quebec City
The live temperature layer of the map (NOAA GFS forecast): watch the cold nights coming hour by hour.
More for Quebec City
Will it rain today in Quebec City? · Open the temperature map on Quebec City
Questions
- When is the last frost in Quebec City?
- On average around 9 May. In an early year the last frost comes by 27 April, in a late one (1 year in 10) after 23 May.
- When is the first frost in Quebec City?
- On average around 13 October. In 1 year in 10 it comes before 1 October, in a mild year not until 30 October.
- How long is the growing season in Quebec City?
- About 157 frost-free days between the last spring frost and the first autumn frost, from 140 in a short year to 175 in a long one.
- When can I plant tomatoes in Quebec City?
- Frost-tender plants such as tomatoes, peppers, beans and courgettes go out after the last frost: after 23 May the risk is down to 1 year in 10. Hardy crops can go earlier.
- How cold does it get in Quebec City?
- The coldest night of winter averages -31.9 °C; the lowest since 1981 was -40.8 °C in 1982.
Frost dates nearby
How these dates are computed
Daily minimum temperature at 2 m from NASA POWER (MERRA-2 reanalysis, public domain), 1981–2025, corrected from the ~50 km grid to the real altitude of Quebec City (6.5 °C per km). For each year: the last night at or below 0 °C before midsummer and the first one after it; the dates are the median and the 10% / 90% of those years. A garden in a frost pocket or a city centre can differ by days. Live temperatures: the temperature layer of the map.