Rain, monthly average temperature and drought as NOAA publishes them, with the listed strikes drawn at the month each contract settles. Past the end of each record a dashed line carries that calendar month’s usual value forward, which is a climatology and carries no information about the weather in that month. Drag across a chart’s history to fit a straight line; double-click to clear. Hover the series for the value at a point, or a marker for the contract’s quote; click a marker to open that contract on IBKR.