Iowa · NWS DMX office

Johnston, IA weather

It is 55°F and cloudy at Ankeny Regional Airport as of Oct 28, 3:55 AM CDT. Overnight: Mostly Cloudy, low near 53°F. Forecast from the National Weather Service, issued Oct 28, 1:26 AM CDT.

Updated Oct 28, 4:27 AM CDT (snapshot)

Current conditions

Temperature

55°F

Cloudy

Wind

Calm

Humidity 88% · dew point 52°F

Pressure · visibility

30.08 inHg

Visibility 10 mi

Observed at Ankeny Regional Airport (KIKV), Oct 28, 3:55 AM CDT. Station readings can lag or be missing.

Alerts for this area

No active NWS alerts cover the Johnston forecast zone right now.

Around the NWS DMX forecast area

No active alerts in zones served by the DMX office near Johnston.

From the alert snapshot of Oct 28, 2026, 5:12 AM EDT. No alerts are active anywhere in Iowa.

For official warnings, check weather.gov and your local authorities. OpenForecast repeats National Weather Service alerts and may be delayed or incomplete. Follow instructions from emergency officials.

Next 24 hours

Hourly forecast for Johnston (local time)
TimeTempForecastPrecip. chanceWind
Wed 4 AM55°FMostly Cloudy0%SSE 5 mph
Wed 5 AM54°FMostly Cloudy0%SSE 5 mph
Wed 6 AM55°FMostly Sunny4%SE 6 mph
Wed 7 AM55°FSlight Chance Showers And Thunderstorms21%SSE 6 mph
Wed 8 AM55°FSlight Chance Showers And Thunderstorms17%SSE 7 mph
Wed 9 AM59°FSlight Chance Showers And Thunderstorms24%SSE 8 mph
Wed 10 AM63°FSlight Chance Rain Showers21%S 9 mph
Wed 11 AM67°FSlight Chance Rain Showers19%S 12 mph
Wed 12 PM70°FSlight Chance Rain Showers17%S 13 mph
Wed 1 PM73°FMostly Sunny12%S 13 mph
Wed 2 PM74°FMostly Sunny13%S 14 mph
Wed 3 PM75°FSunny11%S 15 mph
Wed 4 PM76°FMostly Sunny4%S 15 mph
Wed 5 PM74°FSunny8%S 14 mph
Wed 6 PM73°FMostly Clear14%S 13 mph
Wed 7 PM71°FChance Showers And Thunderstorms38%S 10 mph
Wed 8 PM67°FChance Showers And Thunderstorms45%S 10 mph
Wed 9 PM66°FChance Showers And Thunderstorms39%S 9 mph
Wed 10 PM65°FChance Showers And Thunderstorms41%SSW 9 mph
Wed 11 PM64°FChance Showers And Thunderstorms51%SW 8 mph
Thu 12 AM63°FSlight Chance Showers And Thunderstorms19%WSW 6 mph
Thu 1 AM62°FMostly Cloudy12%W 6 mph
Thu 2 AM61°FMostly Cloudy8%WNW 5 mph
Thu 3 AM60°FMostly Cloudy5%WNW 5 mph

Hourly values come from the NWS gridded forecast for the 2.5 km grid square that covers the city's center point. Conditions elsewhere in Johnston can differ.

7-day forecast

Overnight

Low 53°F

Mostly cloudy, with a low around 53. South southeast wind around 5 mph.

Wednesday

High 76°F·Low 54°F

A slight chance of showers and thunderstorms between 7am and 1pm. Mostly sunny. High near 76, with temperatures falling to around 74 in the afternoon. South southeast wind 6 to 15 mph, with gusts as high as 24 mph. Chance of precipitation is 20%.

Wednesday Night: A chance of showers and thunderstorms between 7pm and 1am. Mostly cloudy. Low around 54, with temperatures rising to around 58 overnight. West southwest wind 5 to 13 mph, with gusts as high as 22 mph. Chance of precipitation is 50%. New rainfall amounts less than a tenth of an inch possible.

Thursday

High 69°F·Low 48°F

Sunny. High near 69, with temperatures falling to around 67 in the afternoon. North northeast wind around 7 mph.

Thursday Night: Rain showers likely after 1am. Partly cloudy, with a low around 48. East wind around 5 mph. Chance of precipitation is 60%. New rainfall amounts between a tenth and quarter of an inch possible.

Friday

High 63°F·Low 51°F

Rain showers likely before 7am, then showers and thunderstorms. Cloudy, with a high near 63. Chance of precipitation is 80%. New rainfall amounts between a quarter and half of an inch possible.

Friday Night: Showers and thunderstorms. Cloudy, with a low around 51. Chance of precipitation is 80%.

Saturday

High 66°F·Low 52°F

Showers and thunderstorms. Cloudy, with a high near 66. Chance of precipitation is 80%.

Saturday Night: A chance of rain showers. Mostly cloudy, with a low around 52. Chance of precipitation is 50%.

Sunday

High 66°F·Low 53°F

A slight chance of rain showers before noon. Mostly cloudy, with a high near 66.

Sunday Night: A slight chance of rain showers after midnight. Mostly cloudy, with a low around 53.

Monday

High 65°F·Low 52°F

A chance of rain showers before noon, then showers and thunderstorms likely. Cloudy, with a high near 65. Chance of precipitation is 70%.

Monday Night: Showers and thunderstorms likely. Cloudy, with a low around 52. Chance of precipitation is 70%.

Tuesday

High 64°F

Rain showers likely. Mostly cloudy, with a high near 64.

Nearby cities

Larger cities in the area

Other cities in Polk County

See every city we cover in Iowa, or check all active alerts.

About this forecast

Forecast office
Johnston is served by the National Weather Service DMX forecast office, forecast zone IAZ060, county zone IAC153.
Location used
The Census Bureau's internal point for Johnston (41.6919, -93.7245), in Polk County. Population: 25,022 (2024 estimate), number 20 of the 27 Iowa cities on this site.
Radar
Nearest NWS radar: KDMX. View it on radar.weather.gov.

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Sources

  • Forecast, hourly forecast, observations and alerts: National Weather Service API, api.weather.gov/points/41.6919,-93.7245 (forecast issued Oct 28, 1:26 AM CDT).
  • Official forecast page: forecast.weather.gov.
  • City location and population: U.S. Census Bureau, Vintage 2024 population estimates and 2024 Gazetteer files.
  • Snapshot taken Oct 28, 2026. The NWS and Census Bureau do not endorse OpenForecast.

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