<P> Evans and his party reached the Fish and Macquarie rivers, and the site of Bathurst . On 7 July 1814, construction of a road across the mountains was begun by William Cox . The work was at the behest of Governor Macquarie. 30 convict labourers and 8 guards completed the road on 14 January 1815 after 27 weeks of hard work . </P> <P> Since the Blue Mountains are rich in coal and shale, mining for these resources began in Hartley Vale in 1865 . J.B. North ran a shale mine in the Jamison Valley in the 19th century, and other operations were set up in several places . Locations for mining activities included the Jamison Valley, the upper Grose Valley, Newnes, Glen Davis and the Asgard Swamp area outside Mount Victoria . Shale mining failed in the long run because it was not financially viable . </P> <P> The climate varies with elevation . At Katoomba, (1,010 m or 3,314 ft) the summer average maximum temperature is around 22 ° C with a few days extending into the 30s (80s--90s ° F) although it is quite common to see maximum temperatures stay in the teens when east coast troughs persist . Night - time temperatures are usually in the teens but can drop to single figures at times . During winter, the temperature is typically around 10 to 11 ° C in the daytime with − 1 ° C or so on clear nights and 3 to 4 ° C on cloudy nights . Very occasionally it will get down to − 3 ° C or slightly lower but usually the coldest air drains into the valleys during calm, clear nights . The Blue Mountains is not known for particularly cold mornings compared to other areas on the Central Tablelands, such as Oberon, Bathurst and Orange . There are two to three snowfalls per year, although settled snow has become less common in recent decades . In the lower mountains, however, the climate is significantly warmer . </P> <P> Annual rainfall is about 1,050 millimetres (41 in) in the Upper Blue Mountains with many misty days . </P>

What is the climate in the blue mountains
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