Winter can be the best time to hike up Table Mountain. You do need to be prepared with the right clothing as the weather can be variable and can also suddenly change. There are quite a few days when its simply not suitable to hike so if your stay is short try to be flexible and have at least one alternative date otherwise you may have to miss out.
Have a backpack with a waterproof cover and a decent rain jackets as well as warm clothing with three to four layers. Waterproof footwear isn’t essential but it can be preferable if the conditions underfoot are wet.
Our good winter days are with clear blue skies, no wind (this can be troublesome in the summer) and 15C to 20C. On top of Table Mountain it can be a lot cooler so this is where you need your additional clothing, gloves and warm hat.
A bonus is also to see waterfalls and streams flowing during your hike. In summer water is scarce on Table Mountain although you will note that the vegetation is always green and in abundance. So come to Cape Town in winter, its quieter, better value for money and Table Mountain is great!