Weightman improved her best world cross country performance at the 2009 IAAF World Cross Country Championships, finishing seventeenth and heading the Australian team to seventh place in the rankings. At the 2009 Christchurch Half Marathon, she was the first past the post to record her first major win on the road running circuit. She competed at her first World Championships in Athletics later that season as Australia's only participant in the women's marathon; she placed eighteenth overall and set a new personal best over the distance with a time of 2:30:42.