Frost Dates in London & the South East cities
late April to early May
November
The growing season here
Cities in this region often have a long, comparatively mild growing season because buildings, paving and dense development retain warmth. Balconies and sheltered courtyards can be especially protected, though exposed roofs, parks and outer suburbs may still frost. These are approximate averages; a local cold pocket, elevation or open aspect can override the urban heat effect.
What it means for sowing & planting out
Hardy salads, peas and many flowers can usually be started early in sheltered ground or containers. Raise tender crops under cover, harden them off gradually, and plant out only once frost risk has passed at your particular site. The city may be mild, but a late cold night can still damage tomatoes, basil, beans and tender bedding. Check the Met Office forecast first.
Tips
Use the warmth of walls and containers, while remembering that pots cool faster than soil. Watering and shade may be more pressing than frost in built-up gardens. Keep fleece available in spring, especially for balconies and gardens on the city's less sheltered edges.
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 18 Sep 2026.