Racegoers are set to shiver through the coldest Derby Day-Cup Day double since 1974. The two biggest races of this year's Spring Carnival will be plagued by chilly southerly winds, further complicating the question of what to wear on race day. Temperatures are forecast to reach tops of 16 degrees in Melbourne on both days, although the mercury is a fair chance to fall short of this mark. The wind chill on Tuesday will make it feel more like 10-12 degrees at times. The last time maximum temperatures on both Derby Day and Melbourne Cup Day were 16 degrees or lower was in 1974. Next Tuesday's forecast top of 16 degrees would make it the coldest Melbourne Cup Day since 2006. If it fails to reach 15 degrees, which is possible, it will be the coldest Cup Day in 22 years. There is also a chance of brief, light showers on Saturday and Tuesday, although with any luck the races will be run during one of the lengthy dry breaks. Since 1875 - when the Melbourne Cup has been run on the first Tuesday of November - the coldest Cup Day maximum was 11 degrees in 1913.