Why are Sydney's sunsets so spectacular this week?

The sunset seen in the suburb of Cheltenham, Sydney, on May 9.

(CNN)Look away if you've seen enough sunsets.

The skies above Sydney put on a spectacular show for locals this week -- and millions more who were bombarded with the spectacle on social media.
But these were no ordinary sunsets.
    A number of factors created the stunning sights, according to Mohammed Nabi from the Australian Bureau of Meteorology.
    "The combined effect of calm weather conditions under the high pressure system, the high cloud in westerly winds over Sydney and the angle of incidence of (sunlight) at this time of the year" all helped, Nabi said.
    So did smoke from a government burn-off.
    During cooler temperatures, the NSW Rural Fire Service carries out controlled "hazard reduction burns" to remove fuel to minimize the risks and damage caused by bush fires.
    They did it last weekend in parts of Sydney and the nearby Blue Mountains. "Smoke released from the burns and trapped in the lower part of the atmosphere will help enhance the effect, albeit temporarily," Nabi said.
    The NSW Rural Fire Service advised residents to keep their windows and doors shut to prevent smoke from entering their homes. Those with respiratory problems were also asked to minimize outdoor activities.
    According to Nabi, the high pressure system is forecast to remain over the southern half of the Australian continent for the next few days.
    So Sydneysiders still have time to take a photo.