2018 Long Range Weather Forecast for Johnston, IA

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How to Read Long-Range Weather Forecasts

Long-range predictions show weather trends in temperatures and precipitation. For example, will the winter be colder or warmer than average? Will there be more or less snow than what's typical for your area?  Our famous predictions (traditionally 80% accurate) are made 18 months in advance, and meant to help you make more informed decisions for long-term planning.

Here on Almanac.com, we provide free long-range forecasts for the next 30 to 60 days covering U.S. and Canadian regions. Find all 12 months of predictions in the annual Old Farmer's Almanac.

Free 2-Month Weather Forecast

AUGUST 2017: temperature 74° (1° below avg.); precipitation 3" (2" below avg. north, 1" above south); Aug 1-4: Showers, cool; Aug 5-13: Sunny, hot; Aug 14-19: T-storms, turning cool; Aug 20-23: Sunny, warm; Aug 24-29: T-storms, then sunny, cool; Aug 30-31: T-storms, warm.

SEPTEMBER 2017: temperature 69° (2° above avg.); precipitation 4.5" (1" above avg.); Sep 1-7: A few t-storms, warm; Sep 8-12: Sunny, hot; Sep 13-16: T-storms, then sunny, cool; Sep 17-23: T-storms, then sunny, cool; Sep 24-30: Scattered t-storms; warm, then cool.

Annual Weather Summary: November 2017 to October 2018

Winter will be milder than normal, with above-normal precipitation and snowfall. The coldest periods will be from late November into early December, from late December into early January, and in early February. The snowiest periods will be in mid-November, early to mid- and late December, and early February. April and May will be cooler and rainier than normal. Summer will be hotter than normal, with slightly below normal rainfall. The hottest periods will be in early and late June, early and late July, and mid-August. September and October will be warmer and rainier than normal.

Map showing Old Farmer's Almanac long range weather region number 10

About the Heartland Region

The Heartland long range weather region includes all or part of the following states: ILLINOIS (Alton, Galesburg, Moline, Quincy, Rock Island), IOWA (Cedar Rapids, Davenport, Des Moines, Sioux City, Waterloo), KANSAS (Kansas City, Olathe, Overland Park, Topeka, Wichita), MISSOURI (Columbia, Independence, Kansas City, Saint Louis, Springfield), NEBRASKA (Bellevue, Fremont, Grand Island, Lincoln, Omaha), SOUTH DAKOTA (Canton, Lennox, North Sioux City, Vermillion, Yankton), WISCONSIN (Baraboo, Fitchburg, Madison, Middleton, Monroe).

Heartland Neighboring Regions

Here are the regions that neighbor the Heartland long range weather region:

Temperature and Precipitation November 2017 to October 2018

Temperature and Precipitation Graph