Is the coast different from the bayside?
Quite. NOAA's 1991–2020 normals put Half Moon Bay at 26.04 inches of rain a year and Redwood City at 19.02, with about 85 percent falling November through March in both (NOAA normals). Highway 280 is a rough dividing line: Pacifica, Half Moon Bay and Daly City take ocean wind and salt spray, while bayside towns from San Mateo to Menlo Park see more fallen limbs and clogged gutters. Heavy storms often come as atmospheric rivers (NOAA). Crews plan from the NWS Bay Area forecast.
Do permits slow a winter reroof?
Every Peninsula city runs its own building department, and San Mateo County handles unincorporated areas such as Emerald Hills, the Highlands and El Granada. Foster City takes applications through its online permit center. Ask your roofer how long your office takes, because an inspection that slips into a rainy week can push the finish date. See the Peninsula permit guide.
What about Eichler and other low-slope roofs?
They're the riskiest roofs to have open in winter, because water pools instead of running off. Crews finish one section at a time and keep drains clear. Read Eichler roof replacement on the Peninsula for the systems used.
How long will a winter job take?
Begin with how long a new roof takes on the Peninsula and add storm days. Coastal jobs lose more days to wind as well as rain. Ask how the contract counts weather days.
What if it rains partway through?
Every stripped section should be dried in the same day; rain during a Peninsula reroof explains tarps and sequencing. Cold rarely matters here, as our cold-weather page shows.
Should I wait for spring?
El Niño 2026–27 on the Peninsula weighs waiting against replacing now. If a storm already did damage, start with my San Mateo County roof leaked in the storm, then request a free estimate.
Every roofer we work with is licensed and insured.
Get a free replacement quoteFrequently asked questions
Is a winter reroof harder in Pacifica than in San Mateo?
Usually, because coastal wind makes tarping and handling materials harder on top of the rain.
Who issues reroof permits in unincorporated San Mateo County?
The county's building department. Cities such as Redwood City and Foster City run their own.
Can an Eichler roof be replaced in the rainy season?
Yes, in dry spells, one section at a time with drains kept open.
Sources
- NOAA 1991–2020 climate normals: Half Moon Bay
- NOAA 1991–2020 climate normals: Redwood City
- NOAA: what are atmospheric rivers?
- National Weather Service, San Francisco Bay Area
- San Mateo County: building permits
- Foster City online permit center
Sources reviewed November 13, 2026. Figures are published estimates and official fees, not quotes. Confirm prices, permits and requirements with your contractor and building department. This page is general information, not legal or insurance advice.