Address reportCitiesIowa › Sioux City

Sioux City, IA

Earthquake hazard, typical weather and growing season from public federal data. Population 82,459.

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 Sioux City address →

Earthquake hazard very-low

Design category A

Very low seismic hazard. Damaging earthquakes are rare at this location and design ground motions are minimal. Ordinary buildings carry essentially no special seismic-detailing requirement. The ASCE 7 Seismic Design Category here is A. (Short-period design value Ss ≈ 0.082 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

85° in July, 10.4° in January

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

MonthHighLowRainSnow
Jan29.5°10.4°0.69"7.7"
Feb34.2°14.8°0.86"8.7"
Mar47.6°25.9°1.76"5.7"
Apr61.1°36.7°3.15"2.3"
May72.3°48.7°3.87"0"
Jun81.9°59.4°4.35"0"
Jul85°63.4°3.35"0"
Aug82.6°60.8°3.94"0"
Sep76.6°51.2°2.84"0"
Oct62.8°37.9°2.2"0.8"
Nov46.8°25°1.27"3.2"
Dec33.4°14.8°0.99"7.6"

NOAA/NCEI 1991–2020 U.S. Climate Normals — station SIOUX CITY GATEWAY AP, IA US, 7.1 mi away.

Growing season zone 5a

161 frost-free days

Last spring frost around April 29, first fall frost around October 7. Roughly half of years see frost outside that window.

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

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