A new car tyre begins life with approximately 8-9mm of tread depth. Legally, you can drive on them until they reach a minimum depth of the tread of 1.6 mm, across 75% of the tyre’s width and all around its circumference. However, consider that safe driving in wet and snowy weather conditions is affected by the tread depth, the pattern design and the rubber compound of the tread of your tyres. On wet or snow-covered roads breaking performance will progressively decline with lower tread depths. On wet roads there is an additional increased risk of aquaplaning with reduced tread depths.
Therefore, check your tyres regularly, reduce your speed on wet and snowy roads and consider replacing your tyres in good time.