Address reportCitiesCalifornia › San Marcos

San Marcos, CA

Earthquake hazard, typical weather and growing season from public federal data. Population 89,387.

Flood zone: it depends on the exact parcel

There is no such thing as a flood zone for a whole city. Two houses on the same street can sit in different zones, and it is the single fact here that changes most over a short distance. So this page does not guess one.

Look up a specific San Marcos address →

Earthquake hazard high

Design category D

High seismic hazard. Strong ground shaking is expected over the life of a building. Substantial seismic-resistant design, detailing, and inspection are required by code. The ASCE 7 Seismic Design Category here is D. (Short-period design value Ss ≈ 0.898 g — the standard headline measure of ground-shaking hazard.)

USGS Seismic Design Web Services (ASCE 7), assuming Site Class D — stiff or unknown soil. Real soil conditions can move the category either way.

Typical weather

89° in August, 43.8° in December

Thirty-year averages, not a forecast. Any individual year can differ substantially.

MonthHighLowRainSnow
Jan68.8°44.8°3.19"0"
Feb68.7°45.9°3.57"0"
Mar71°48.9°2.2"0"
Apr74.2°51.8°0.99"0"
May76.7°56.4°0.35"0"
Jun81.9°60.2°0.09"0"
Jul87.2°64.4°0.12"0"
Aug89°65.3°0.06"0"
Sep86.9°63.1°0.16"0"
Oct80.8°57.3°0.57"0"
Nov74.6°49.1°1.08"0"
Dec68°43.8°2.14"0"

NOAA/NCEI 1991–2020 U.S. Climate Normals — station ESCONDIDO #2, CA US, 5.3 mi away.

Growing season zone 10a

365 frost-free days

Last spring frost around n/a, first fall frost around n/a. Roughly half of years see frost outside that window.

2023 USDA Plant Hardiness Zone Map and NOAA/NCEI 1991–2020 frost normals.

What this page does not tell you

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