Monthly temperature data for Aizwal in 2007 is shown on the Figure left. This meteorological station is 40km west of the main vineyards, but thought to be representative. Since temperatures rarely fall below 12 degrees C there is no dormant period for the vine and technically two grape crops could be produced each year.
To produce high quality grapes suitable for wine-making a long dry ripening season is required and the problem for Champhai is that by late May the area is already receiving heavy rainfall. It is difficult to see how grapes with good phenolic and sugar ripeness could regularly be produced here.
Average monthly rainfall at Aizwal is shown on the Figure right. The average annual total is just over 2,000mm; individual years vary from ca. 1,500 – 3,000mm. This is much more rainfall than would be considered suitable for a quality vineyard and causes a number of problems. Fruit must be picked before they are rain damaged, and this is likely to be before they are properly ripe. Damp conditions also encourage mildew, especially with V. vinifera varieties. Consequently, Champhai is planted with V. labrusca varieties.