Its best not to apply weed control during December and January as the control will be less effective and grass growth is not sufficient to replace any weeds that are removed. 

The reduced daylight at this time of year means some lawns will naturally thin, water logging can have the same effect as the saturated root zone deprives the plant of the oxygen and nutrients it needs, once, air, light and warmth returns in spring the grass usually bounces back. Aeration of the soil can help improve the conditions.

It’s very important for the health of the lawn to remove any debris, leaves etc as soon as possible after they fall as these can also block sunlight and smother the plant  promoting disease, moss and surface worm activity.

If you can, remove any furniture from the lawn and prune back overhanging bushes and branches to increase light. 

Moss can be an enemy this time of year, so treat it, it may need several applications across the cooler months if conditions prove to be good for moss growth. If the moss is heavy it will likely need to be physically removed by raking or scarification once conditions allow. 

On the South Coast, over the last few years, as the climate has changed, grass has continued to grow through the winter months, so, if you can, and the ground conditions allow, continue to mow on a higher setting but less frequently. If the temperatures stop growth then stop cutting until it returns. As always ensure the mower blade is sharp and do not cut more then 1/3 of the grasss blade at any time.

Grass can be vunerable to disease this time of year so keep your eye out for unexpected changes. 

If the grass is frosted over try not to walk on it until it thaws.