ZIP code · Great Falls · Montana · United States
ZIP code 59403 — Great Falls
ZIP code 59403 serves Great Falls, Montana.
- Postal code
- 59403Single source Value from one source, not cross-checked.
- City
- Great Falls
- County
- Cascade
- State
- Montana
- Country
- United States
- Coordinates
- 47.5002, -111.3008 — precision precise (locality)
View on OpenStreetMap - USDA hardiness zone
- 4b (-25 to -20 °F)Planting / growing zone from the 2023 USDA Plant Hardiness Zone Map: average annual extreme minimum temperature, 1991–2020.
- Time zone
- America/Denver (UTC−7 / UTC−6 DST)
- Area code
- 406Telephone 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 59403 with another ZIP · ZIPs within 25 miles · distance from 59403
Climate — monthly normals
Warmest month Jul (avg high 86°F), coldest Jan (avg low 18°F).
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high °F | 37 | 39 | 48 | 58 | 67 | 75 | 86 | 84 | 73 | 59 | 45 | 37 |
| Avg low °F | 18 | 19 | 25 | 33 | 42 | 50 | 55 | 53 | 45 | 36 | 26 | 20 |
| Precip in | 0.6 | 0.6 | 0.6 | 1.8 | 2.7 | 2.7 | 1.3 | 1.3 | 1.4 | 1.1 | 0.7 | 0.6 |
NOAA 1991–2020 climate normals from the nearest station: GREAT FALLS 16ST (1.3 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