The Purple Guide to Health, Safety and Welfare at Music and Other Events — Weather[1]
Summary
Requires weather hazards in the event risk assessment, planned against conditions including extremes expected only once every 10 years, with bespoke forecasting generally needed and, for larger events, a forecaster on site. Specification factors go beyond temperature: feels-like temperature, lightning risk, fog, UV, ground temperatures at depth, winds at height, pollen, wave height for coastal events, snow depth, and soil moisture for site trafficability. Met Office severe weather warnings (yellow/amber/red) are a floor, not a clearance: absence of a warning does not mean conditions suit every event. Worker heat provisions include scheduling to cooler hours, controlled work rates, shade, and always-available water; public heat provision must be planned in consultation with those providing medical and first aid facilities. Cold provisions note fabric structures have almost no snow-load capacity, with heating to at least 12C and clearing of valley accumulations as mitigations. All temporary structures must be certified for wind resistance. Lightning: around 300,000 UK strikes yearly with 30-60 people struck and about three deaths; controls include monitoring, a defined list of safe structures, an evacuation plan and worker briefing; the 30/30 rule applies (flash-to-thunder 30 seconds or less means act; maintain shelter 30 minutes after the last thunderclap); and care must be taken that the response avoids large crowd movements that could cause more serious risks.
So what
Two provisions matter beyond weather. The lightning paragraph requiring responses to avoid dangerous crowd movement is the mitigation-must-not-create-crush test restated inside a hazard procedure - the lightning plan and the crowd plan are the same plan, and lightning is the one hazard arriving with numeric stop (30/30) and restart (30 minutes) criteria built in, a worked example of a pre-agreed show-stop trigger. And the public-heat paragraph is the only place in the Guide that requires the medical provider's input into another domain's plan - citable whenever the medical director's upstream role needs a source. The 30/30 figures converge with the NCAA/NATA lightning guidance already on the shelf.