ZIP code · Alton · Iowa · United States
ZIP code 51003 — Alton
ZIP code 51003 serves Alton, Iowa.
- Postal code
- 51003Single source Value from one source, not cross-checked.
- City
- Alton
- County
- Sioux FIPS 19167
- State
- Iowa
- Country
- United States
- Coordinates
- 42.9782, -96.0173 — precision precise (locality)
View on OpenStreetMap - Population
- 1,815 (ZCTA, ACS 5-year)
- Population density
- 33 / sq mi
- Land area
- 54.4 sq mi (140.8 km²) (ZCTA, ACS 5-year)
- Median household income
- $85,909
- Per-capita income
- $43,998
- Median age
- 34.7
- Households
- 708
- Housing units
- 762
- Median home value
- $226,300
- Median gross rent
- $750 / month
- Congressional district
- IA-4 (119th Congress)
- USDA hardiness zone
- 5a (-20 to -15 °F)Planting / growing zone from the 2023 USDA Plant Hardiness Zone Map: average annual extreme minimum temperature, 1991–2020.
- Time zone
- America/Chicago (UTC−6 / UTC−5 DST)
- Area code
- 712Telephone area codes serving this ZIP (NANPA central-office assignments). A ZIP and an area code are different boundaries; at a border both codes may apply.
Tools: compare 51003 with another ZIP · ZIPs within 25 miles · distance from 51003
Map of ZIP code 51003
Climate — monthly normals
Warmest month Jul (avg high 85°F), coldest Jan (avg low 9°F).
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 27 | 33 | 46 | 61 | 73 | 82 | 85 | 82 | 77 | 64 | 46 | 32 |
| Avg low °F | 9 | 14 | 25 | 36 | 48 | 59 | 62 | 60 | 51 | 39 | 25 | 15 |
| Precip in | 0.7 | 0.9 | 1.7 | 3.0 | 4.2 | 4.5 | 3.5 | 3.4 | 3.2 | 2.5 | 1.4 | 1.0 |
NOAA 1991–2020 climate normals from the nearest station: SIOUX CTR 2 SE (8.7 mi) · NOAA NCEI
Places in ZIP 51003
- 3 schools
- 1 restaurants & cafés
- 3 parks
- 1 libraries
- 2 post offices
- 3 places of worship
- 1 police & fire stations
Places mapped inside this ZIP’s ZCTA area in OpenStreetMap. OSM is community-maintained: counts reflect what has been mapped, and completeness varies by area — treat them as at-least figures. © OpenStreetMap contributors (ODbL) · Methodology
About this page
US ZIP codes have five digits. They are postal routing areas, not administrative boundaries: a ZIP can span more than one city or county, and the city shown is the primary USPS name for that code.
GeoNames · U.S. Census Bureau (ACS) · U.S. Census Bureau · NOAA NCEI · usda-phzm. Data generated on 2026-08-21. Methodology · Report an error on this page