Frost Dates in Northern Ireland
mid to late May
late October to early November
The growing season here
Northern Ireland's maritime climate is often mild and damp, with a reasonably long growing season in sheltered lowland and coastal gardens. However, inland hollows and higher ground can catch late frost, while wind can slow tender growth. These are approximate regional averages only: exposure, altitude, aspect and local cold-air drainage all matter more than one calendar period.
What it means for sowing & planting out
Sow hardy crops outside when soil conditions are right, and raise tender vegetables and flowers under cover for a stronger start. Plant out tomatoes, beans, courgettes, squash and tender bedding only after frost risk has passed for your own garden. Harden plants off gradually, have fleece ready for a late chill, and check the Met Office forecast before planting out.
Tips
Shelter crops from wind and improve drainage where persistent rain leaves soil cold. Use cloches or fleece to protect tender plants during unsettled spring weather. Coastal sites may be milder, but inland gardens should ask a local garden centre about their usual frost pattern.
These are approximate regional averages - frost varies with altitude, frost pockets, coast and aspect. Check the Met Office forecast for your area before acting. Page updated 19 Sep 2026.