Last Frost Date Portsmouth: Frost Dates, Late Frost Risk & Growing Season
When is the last spring frost and the first autumn frost in Portsmouth? Frost dates from 30 years of data, the risk of late frost, frost-free days and planting dates.
The frost season in Portsmouth
- Last frost (average): April 11
- In 1 year out of 10 it still freezes on April 23.
- First frost: November 13
- Frost-free season: 213 days
- Frost after 15 May: in 0 % of years
Frost days per month in Portsmouth
- January: 10.2 · 2 °C
- February: 9.4 · 2 °C
- March: 5.6 · 3 °C
- April: 2 · 4 °C
- May: 0 · 7 °C
- June: 0 · 10 °C
- July: 0 · 12 °C
- August: 0 · 12 °C
- September: 0 · 10 °C
- October: 0.3 · 7 °C
- November: 4 · 4 °C
- December: 8.9 · 2 °C
- Matched to the average lows of a weather station 52 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.