Interpreting uncertainty visualizations can be cognitively demanding, and individual differences, such as personality traits, may affect how people perceive such visualizations. While prior research has explored personality and cognitive load independently, few studies have investigated their combined influence on perception and decision-making in uncertainty visualizations. We conducted an experiment based on a wildfire evacuation task that compared textual and visual representations of uncertainty. Participants completed the NASA Task Load Index to assess perceived cognitive workload and a Big Five personality traits test to measure individual differences in personality. Consistent with prior findings, visual representations led to higher evacuation rates and faster decision times compared to textual representations. However, textual representations were associated with lower perceived cognitive workload. Personality traits significantly impacted decision-making behavior and perceived cognitive workload. Participants high in extraversion, neuroticism or openness were more likely to evacuate, while those high in agreeableness or conscientiousness were less likely to evacuate and tended to take more time to decide. Additionally, agreeableness and conscientiousness were positively correlated with perceived cognitive workload across all representations, whereas neuroticism and openness showed negative correlations, though only in certain representations. These findings offer new insights into how personality affects the perception and cognitive load in the context of uncertainty visualizations.