Nasdaq is actually a stock exchange located in New York and they open for business by 9:30 AM American time which equates to around 4:30 PM South African time (remember South Africa is 7 hours ahead of New York).
When Nasdaq opens for the day, there is usually a flurry of activities which causes higher volatility which lasts about 3 hours from opening.
The best time you can trade Nasdaq in South Africa is from 4:30 PM till 7:00PM South African time because early morning activities will be at their peak at the Nasdaq office in New York. You will tend to see better price movement and better candlestick formation.
Hope this helps