For anyone who arrived this spring, this is the part of the local climate that surprises. The hot weather is not in July. It is in September and October, when the marine layer breaks down and the offshore flow sets up.

What people do about it, in ascending order of commitment:

1. Box fans and a night-flush routine. All the windows open after sunset, all of them shut by 8am.
2. A window or portable A/C unit for the bedroom. One room cool is enough for most households in a 4-day heat spell.
3. A heat pump / mini-split. Increasingly default in remodels, because it handles the 2 weeks of heat and replaces a gas furnace for the sixty nights of winter that need one. There are rebate programs running through the county or the state, and they are worth 10 minutes before a purchase.

The other September items come due at the same time: gutters cleared of whatever the trees dropped, an address confirmed in SMC Alert, and a clear idea of what a public safety power shutoff would mean for the household.

Three practical consequences:

• Outdoor evening events need a layer. A 6-8 degree temperature drop on a windy evening is larger than the drop overnight.
• Coyote Point is at its best. This is the wind kiteboarders and windsurfers wait for all winter. Sailing or not, the bayshore on a breezy afternoon is one of the more alive places in the county.
• The hills stay grey longer. West of Alameda de las Pulgas the morning fog burns off an hour or two later than the flats. Normal for June and July, and not a sign of how the whole summer will go — see the fog line.

The compensation arrives in September, reliably the warmest, stillest, best-weather month of the year here.