The main reason cyclones develop this time of year in the Pacific Islands is because of warmer sea surface temperatures.
Moist, warm air on the sea surface acts as a fuel for any turbulence above it, feeding it with hot rising air and adding to the extreme turbulence.
Will this cyclone affect New Zealand? Some computer models suggest it might be nearby this weekend, but there are still a lot of variables. The position of highs in the region is one of them.
These are currently blocking the path of the cyclone, so if they stay put, they will deflect the storm away from the country.
The cyclone is also being steered by winds at very high altitudes. These are taking it on a southwesterly path, but at this stage it is impossible to say just how close it will get to New Zealand.
What we do know is that as it heads into our cooler waters it will definitely get a lot weaker.
It may still mean strong winds and rain, but not the damaging cyclone it is at the moment
If you wish to make a donation to those affected by Cyclone Evan, text “Evan” to 4741 to make an instant $3 donation to the Fijian Charitable Trust.