There are large daily and annual temperature fluctuations (see temperature variability). The average January temperature is −4 °C/25 °F; that of July is 28 °C. The annual rainfall is 80 mm/3 in in the north east and 300 mm in the mountains, the largest amount of rainfall being recorded in spring and winter. Evidence of vine-growing in the country dates back to the 3rd century bc. Greek and Roman writers report that grapes were cultivated in Marghian (the Murghab Valley) and in Aria (the Tejen Valley). The Kopetdag ravines still have a great diversity of wild vines that have served as a basis for many indigenous varieties. Different wine vessels depicting grape bunches found during excavations of the village of Baghir near the capital Ashkhabad testify to the fact that Turkmenistan has a long history of winemaking.