We propose that visceral states can influence beliefs through "visceral fit": People will judge states of the world associated with their current visceral experience as more likely. We found that warmth influenced belief in global warming (Studies 1-3) and that thirst impacted forecasts of drought and desertification (Study 5). These effects emerged in a naturalistic setting (Study 1) and in experimental lab settings (Studies 2, 3, and 5). Studies 2-6 distinguished between 3 mechanistic accounts: temperature as information (Studies 2 and 3), conceptual accessibility (Studies 4 and 5), and fluency of simulation (Studies 6a and 6b). Studies 2 and 3 ruled out the temperature as information account. Feeling warm enhanced belief in global warming even when temperature was manipulated in an uninformative indoor setting, when participants' attention was first directed to the indoor temperature, and when participants' belief about the current outdoor temperature was statistically controlled. Studies 4 and 5 ruled out conceptual accessibility as the key mediator: Priming the corresponding concepts did not produce analogous effects on judgment. Studies 6a and 6b used a causal chain design and found support for a "simulational fluency" account. Participants experiencing the visceral state of warmth constructed more fluent mental representations of hot (vs. cold) outdoor images, and those who were led to construe the same hot outdoor images more fluently believed more in global warming. Together, the results suggest that visceral states can influence one's beliefs by making matching states of the world easier to simulate and therefore seem more likely.