What type of weather information is crucial for determining the safety of an outdoor event?

Real-time forecasts and warnings are essential for determining the safety of an outdoor event because they provide the most up-to-date information regarding current weather conditions and any imminent threats. This includes critical data such as severe weather alerts, storm warnings, or changing conditions that could pose risks to attendees and participants. Real-time information allows event organizers to make informed decisions about safety measures, whether it's choosing to postpone, relocate, or adapt to the current weather situation.

On the other hand, annual precipitation records and historical weather patterns may provide context on weather trends and potential risks over a longer term but lack the immediacy and specificity required for the safety of an upcoming event. Meanwhile, current temperature trends do offer insight into conditions but do not account for sudden weather changes or severe conditions that may affect safety in real-time. Thus, while these options are valuable in understanding weather patterns broadly, they do not compare to the critical need for real-time information in order to ensure safety during an outdoor event.