Orange is in line to record a month's worth of rain in the next week as a cooler change crosses over the Orange region to mark the start of Autumn.

The Bureau of Meteorology is predicting rain for Orange from Tuesday through to Friday, with up to 70 millimetres anticipated to fall in that time.

Orange's average monthly rainfall in March is 66.4mm.

Our best chance of precipitation is on Wednesday and Thursday, with an 80 per cent chance of rain - up to 20mm - on those days and there's a hope for weekend rain too.

Orange hit a maximum of 30 degrees on Monday but the mercury is tipped to plummet for the rest of the week, with a maximum of 20 degrees Celcius on Tuesday.

The top temperature on Wednesday and Thursday is forecast to be 20 and 19 degrees respectively.

The cool change and predictions of rain come on the back of a thick tongue of tropical humidity that will creep south over the interior of New South Wales this week, spreading widespread rain and storms across much of the Central Tablelands region.

The humidity will track south this week and will meet another moisture feed from the east that'll enhance the system, helping spread double digit rainfall by Thursday night.

Orange's weather station at the airport has recorded 132.8mm in January and 60mm in February to kick off 2020.