Colorado's monsoon season turns Boulder afternoons into a predictable lightning and hail window each July through September — the mechanism and safety basics.

Boulder's afternoon storms build over the foothills before they reach downtown — how to set up National Weather Service and phone alerts that catch that lead time.

Boulder's summer thunderstorm cycle fires reliably between 1 and 7 p.m. — the meteorology behind the pattern and how to plan any outdoor ride around it.