Last Frost Date Grand Forks: Frost Dates, Late Frost Risk & Growing Season
When is the last spring frost and the first autumn frost in Grand Forks? Frost dates from 30 years of data, the risk of late frost, frost-free days and planting dates.
The frost season in Grand Forks
- Last frost (average): May 15
- In 1 year out of 10 it still freezes on May 23.
- First frost: September 28
- Frost-free season: 136 days
- Frost after 15 May: in 43 % of years
Frost days per month in Grand Forks
- January: 30.9 · -20 °C
- February: 28.2 · -17 °C
- March: 29.9 · -9 °C
- April: 19.7 · -2 °C
- May: 4.6 · 5 °C
- June: 0 · 12 °C
- July: 0 · 14 °C
- August: 0 · 13 °C
- September: 1.3 · 7 °C
- October: 14.9 · 0 °C
- November: 28 · -8 °C
- December: 31 · -15 °C
- Matched to the average lows of a weather station 15 km away – accurate to about ±1–2 weeks.
- Daily minimum temperatures 2 m above ground over 30 years (1991–2020), NASA POWER; station data: Deutscher Wetterdienst (CC BY 4.0). Ground frost can form while the air at 2 m is still +2 to +3 °C.