ZIP code · Red Oak · Iowa · United States

ZIP code 51591 — Red Oak

ZIP code 51591 serves Red Oak, Iowa.

Postal code: 51591
Single source Value from one source, not cross-checked.
City: Red Oak
County: Montgomery
State: Iowa
Country: United States
Coordinates: 41.0303, -95.1562 — precision precise (locality)
View on OpenStreetMap
USDA hardiness zone: 5b (-15 to -10 °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: 712
Telephone 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 51591 with another ZIP · ZIPs within 25 miles · distance from 51591

Climate — monthly normals

Warmest month Jul (avg high 86°F), coldest Jan (avg low 13°F).

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Avg high °F	33	38	51	63	73	83	86	85	78	66	50	37
Avg low °F	13	16	28	38	51	61	66	63	53	41	28	18
Precip in	0.9	1.1	2.0	3.8	6.0	5.4	4.0	3.9	3.6	3.3	1.9	1.4

NOAA 1991–2020 climate normals from the nearest station: RED OAK (4.8 mi) · NOAA NCEI

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 · NOAA NCEI · usda-phzm. Data generated on 2026-08-21. Methodology · Report an error on this page