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A joint service of the UK Ag Weather Center and the National Weather Service.
Precision Agriculture Weather Forecast For OBRIEN CountyFor Your Farm PointAgCast...Click here. Regional Hourly Observations For OBRIEN County Issued at 100 AM CDT TUE AUG 18 2026 NORTHWEST IOWA CITY SKY/WX TMP DP RH WIND PRES REMARKS CHEROKEE CLOUDY 70 66 88 S6 29.98F TC 21 DENISON MOCLDY 68 68 100 CALM 30.03S TC 20 ESTHERVILLE MOCLDY 66 63 90 S7 29.96F TC 19 LE MARS MOCLDY 72 72 100 S8 29.98S TC 22 MAURICE MOCLDY 70 70 100 S6G12 29.99S TC 21 SHELDON CLOUDY 72 72 100 SW9 29.96S TC 22 SIOUX CITY LGT RAIN 71 68 90 S6 30.02R TC 22 6HR MIN TEMP: 70; 6HR MAX TEMP: 81; 6HR PCP: TRACE; SPENCER CLOUDY 70 65 84 SW7 29.98S TC 21 6HR MIN TEMP: 68; 6HR MAX TEMP: 79;
Current Agricultural Weather Conditions in Iowa Based on observations at 1200am CDT, Tuesday August 18, 2026 Across Iowa...temperatures are near 72 degrees west, near 72 degrees central, and near 67 degrees east. Current sky conditions are cloudy west, cloudy central, and clear east. In the west, relative humidity is near 84%, and the dew point is near 67 degrees. In the central part of the state, relative humidity is near 78%, and the dew point is near 65 degrees. In the east, relative humidity is near 87%, and the dew point is near 63 degrees. The livestock heat stress category is no stress west, no stress central, and no stress east. Winds are from the south at 5 mph west, where conditions are favorable for spraying. Winds are from the south at 5 mph central, where conditions are favorable for spraying. Winds are from the southwest at 6 mph east, where conditions are favorable for spraying. Based on current available observations, the highest temperature is 72 degrees at Sioux City and Des Moines. The lowest temperature is 62 degrees at Mason City.
Current NOWCAST not available: Nowcasts are not issued routinely during fair weather. Only when precipitation or other significant weather is occuring in this county will these forecasts be issued. Currently, there is no short term forecast in effect. Hazardous Weather Outlook For OBRIEN County,IA 926 PM CDT Mon Aug 17 2026 DAY ONE Tonight. Isolated to scattered thunderstorms may become strong to severe producing 1 inch hail and wind gusts to 60 mph. A second round of strong to severe storms is possible after midnight. These storms could produce two inch hail and wind gusts to 70 mph. DAYS TWO THROUGH SEVEN Tuesday through Sunday. Scattered thunderstorm risks continue through Wednesday. Severe storm risks remain focused mostly Tuesday afternoon and early evening along and south of I-90. SPOTTER INFORMATION STATEMENT Spotter activation may be needed.
7-Day Forecast For OBRIEN County, IA 1209 AM CDT Tue Aug 18 2026 REST OF TONIGHT TUESDAY TUESDAY NIGHT WEDNESDAY WEDNESDAY NIGHT THURSDAY THURSDAY NIGHT FRIDAY FRIDAY NIGHT SATURDAY SATURDAY NIGHT SUNDAY SUNDAY NIGHT MONDAY
Medium & Long Range Outlook For Iowa
IOWA
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6 TO 10 DAY 8 TO 14 DAY 30 DAY 90 DAY
AUG 23-27 AUG 25-AUG 31 JUN JUN-AUG
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Temperature: Above Above
Precipitation: Normal Normal
.... Medium and long range outlooks provided by NCEP/K. Thomas Priddy
Almanac Information Historical Weather And Climate Facts For Today ////////////////////////// AUGUST 18TH...HISTORIC WEATHER EVENTS ...1925... During the late morning hours a severe hailstorm struck southeastern Iowa completely destroying crops along a path six to ten miles wide and 75 miles long. The hail also injured and killed poultry and livestock, and caused a total of 2.5 million dollars damage. The hailstorm flattened fields of corn to such an extent that many had to leave their farms in search of other work. It was one of the worst hailstorms of record for the nation. (The Weather Channel) ...1983... Hurricane Alicia, a category 3 storm made landfall near Galveston. Winds gusted to 130 mph with a storm surge of 12 feet. 22 tornadoes were spawned. Parts of Houston received 11 inches of rain. 12 people died and 1800 were injured. Total damage estimated at $3 billion. (NWS Louisville) ...1987... Thirteen cities in the eastern U.S. reported record high temperatures for the date, including Orlando FL with a reading of 98 degrees, and Portland ME with a high of 94 degrees. Newark NJ reached 90 degrees for the thirty-sixth time of the year, their second highest total of record. (The National Weather Summary) ...1988... Twenty-two cities, from the Carolinas to the Upper Ohio Valley, reported record high temperatures for the date, pushing the total number of daily record highs since the first of June above the 1100 mark. Afternoon highs of 102 degrees at Greensboro NC and 105 degrees at Raleigh NC equalled all-time records. Evening thunderstorms in Montana produced wind gusts to 75 mph at Scobey. (The National Weather Summary) (Storm Data) ...1989... Thunderstorms over the Middle Atlantic Coast Region and the Upper Ohio Valley produced torrential rains in eastern Virginia during the late morning and afternoon hours. Totals ranged up to twelve inches at Yorktown. Williamsburg VA was deluged with 10.78 inches of rain between 6 AM and 10 AM, with 6.72 inches reported in just two hours. Flash flooding caused nearly twelve million dollars damage in Accomack County VA. Early evening thunderstorms in the Central High Plains Region produced walnut size hail and wind gusts to 80 mph around Casper WY. Thunderstorms produced locally heavy rains in the Yellowstone Park area, causing fifteen mudslides. (The National Weather Summary) (Storm Data) ...1995... At 1 pm Bowling Green recorded an exceptionally high dew point of 81 degrees. (NWS Louisville) Ag Weather Center, Department of Biosystems & Agricultural Engineering, University of Kentucky | ||||||||||