Besides the continued wet weather that has plagued the fall harvest season, the other major story has been the lack of cold temperatures. The featured map presents the fall season to date (ending Thursday) minimum low temperature for the long term climate sites within Iowa. These maps tend to be a bit noisy with local micro-climates heavily influencing low temperatures early in the cold season. The map generally shows much of southeastern Iowa yet to experience a freezing temperature. Such temperatures appear possible Saturday morning, but milder temperatures are expected to quickly return with overnight lows remaining well above freezing.

Generate This Chart on IEM Website

The IEM curates an archive of one minute interval ASOS data collected by NCEI. The data collection method used by NCEI for this dataset leads to a day or two data availability delay. Anyway, when interesting weather phenomena happen around the country, it is interesting to see what the one minute interval observations show for the event. On Monday, Melbourne Florida set a all-time 24 hour precipitation record of 11.51" for the site. The featured chart shows the one minute interval data from this event with the black line showing the accumulation and the other lines showing computed rainfall rates over various windows of time. The one minute data is not complete, so the plotted total comes up just short of the official total. That aside, it is remarkable to see the maximum one minute accumulation was just 0.03"! If you follow the "heavyrain" feature tag, you'll find many of examples of this plot for significant rainfall events for other locations in the country. Rainfall rates for those events are always much higher.

Generate This Chart on IEM Website

Muggy for November air was again present over the eastern half of Iowa on Tuesday with dew point readings into the lower 60s! The featured chart presents hourly dew point maximum values over the period of record for Cedar Rapids. Plenty of hours with new maximum or tied maximum values are indicated occurring on Tuesday. The overall maximum value of 64°F tied a value from 1 Nov 2000. This is all based on available hourly reports and there is not a daily high and low value reported like for air temperature. The humid air will finally depart the state on Wednesday with temperatures much closer to average than what our recent weather has been.

Generate This Chart on IEM Website

For November, it was rather humid on Monday with dew point readings into the lower 60s for much of Iowa. The featured chart looks into the dew point climatology by wind direction for Des Moines during November. The black line represents the simple average and intuitively shows the highest dew point readings with a southerly wind and lowest when the wind is from the northwest. The observations for yesterday are denoted by the black dots and show values well above the 95th percentile for the south-southeasterly direction. As was the case for much of September, the elevated humidity levels are again fueling significant rainfalls with more on the way lasting into Thursday.

Generate This Chart on IEM Website

After only one day with wide spread sub-freezing temperatures during October, November has started off mild as well with the forecast for the first week of month remaining well above freezing for low temperatures. It continues to be remarkable to denote how much warmer low temperatures have been compared with climatology. The featured chart presents a comparison between various daily climatology sources for Ames for November. The tan bars represent simple period of record averages and the three lines show the last three renditions of the official climatology. The "pull" of climatology is obvious with days getting progressively cooler and this "pull" will get harder to fight against if our current mild weather pattern is to continue.

Generate This Chart on IEM Website

The pleasant-for-late-October weather continued on Thursday with highs in the 60s and even low 70s for Iowa. For places like Des Moines, it was the 12th straight day with a high temperature above average. The featured map looks into the current daily high temperature streaks above (red positive numbers) or below (blue negative numbers) average based on the first order NWS CLImate reporting sites. Today's (30 October) high temperatures will struggle to keep the streaks going at a number of locations, but warmer weather is expected again on Saturday and lasting well into next week. Significant cool/cold weather continues to be absent so far this fall season!

Generate This Chart on IEM Website

Waterloo tied a record high from 1927 of 78°F for 28 October. The featured chart looks into the daily high and low temperature climatology during October for Waterloo. The combined shaded region represents the range between the daily record low and high temperature. The green area denotes the range between the daily average low and high temperature. The brown bars are 2026 values with the yellow outlined dot denoting tied or newly set records for 2026. Interesting, the 28 October record high is the only one for the month still below 80°F, so it was the lowest record to beat for the month. Even with it only being 78°F, the record stood untied for 99 years!

Generate This Chart on IEM Website

While Tuesday was not as warm as it recently has been, temperatures were still rather mild for most of the state with the exception of northwestern Iowa again for high temperatures. On the other hand, low temperatures were mild for the entire state as significant cold or even freezing temperatures this October have been non-existent except for the brief freeze on the 17th. The featured map looks into the low temperature climatology for the last week of October based on the current official NCEI climatology. On average, low temperatures should be much cooler than they have been with practically all of the state shown in the 30s. The forecast to end October has very little of such chilly temperatures as a number of locations in Iowa will finish the month without a freeze/frost.

Generate This Chart on IEM Website

Your location within Iowa made a big difference if you found Monday to be an excellent fall day or not. The featured map presents an analysis of Iowa airport high temperatures. A range of over 30°F is shown with Centerville reaching 79°F and Sheldon + Sioux County only reaching 45°F! This same gradient looks to repeat itself on Tuesday and even Wednesday before warmer air pushes north and northwestern Iowa is not left out again on the continued nice fall weather that the rest of the state has enjoyed for just over a week now.

Generate This Chart on IEM Website

The very nice October weather continued on Sunday for most of Iowa with only northwestern Iowa experiencing a bit chilly temperatures and some light rain. The rest of the state enjoyed yet another day with above average temperatures. The featured calendar chart shows daily high temperature departures from average for Des Moines this October. Only the 16th is shown having a significantly colder than average high temperature. The warm temperatures look to continue this week with mostly dry conditions.

Generate This Chart on IEM Website

A week of wonderful fall weather looks to last into the weekend prior to cooler temperatures along with rain chances to start off next week. There have been plenty of daily high temperatures into the upper 70s this week and one may wonder how much longer into the fall season can such temperatures last? The featured chart attempts to answer that question by plotting the latest calendar date a given high temperature was observed at or above a given threshold. The first item to notice is how anomalous the 15 December 2021 event was with a high temperature of 74°F that day! Values in the mid to upper 70s are possible for a few weeks yet, so there is still time for such warmth to occur!

Generate This Chart on IEM Website

The Hazardous Weather Outlook (HWO) is a text product narrative issued by National Weather Service Weather Forecast Offices (WFO) highlighting hazardous weather threats over the coming few days. This product has been deprecated by many WFOs as no longer being useful / containing redundant information found in other products. The product does live on though for some WFOs with the featured map displaying the number of HWOs issued so far this month by WFO. For the Iowa WFOs, NWS Des Moines stopped HWOs at the end of September and NWS Omaha stopped back in June. For those curious, the oldest HWO found in the IEM archive dates back to 1994 and was issued by NWS Hastings, NE.

Generate This Chart on IEM Website

USDA NASS released their weekly crop progress update on Monday and Iowa, among other Midwestern states, remains a bit behind on soybean harvest progress as of this past Sunday. The featured map presents the most recent NASS estimated percentage of acres harvested along with a percentage points difference from a ten year average approximately valid for 18 October. Better weather this October vs September has certainly helped progress to be made, but many fields remain quite wet and much more drier weather is needed. You can generate this same map for corn and find a similar story for Iowa. Soybeans tend to be harvested first in Iowa as the crop matures sooner and farmers have a desire to get it out of the field before colder November weather brings chances of snow!

Generate This Chart on IEM Website

It is difficult to imagine more perfect fall weather than what we had on Monday with most locations having highs in the 60s, lows in the 40s and not much for wind. The featured chart looks into the daily frequency of having a high in the 60s, a low below 50°F, and a max sustained wind speed below 20 MPH for Des Moines. This type of weather is clearly isolated to the spring and fall seasons with combined frequency peaks, shown by the black line, occurring during each season. The month of October has the highest frequency at around 17%, so this is the time of year for such wonderful weather!

Generate This Chart on IEM Website

Sub-freezing temperatures finally visited Iowa Saturday morning. It was one of the latest first freeze dates for any location in the state on record. Rewording, since at least 1893 and prior to 2026, at least one long term climate site has seen a sub-freezing temperature by 16 October. The featured map presents an analysis of 15 minute interval Real-Time Mesoscale Analysis (RTMA) minimum temperature during Saturday morning. Only some parts of southern Iowa appeared to miss out, but temperatures were not necessarily cold enough for a wide spread "killing freeze". Temperatures were warmer on Sunday and a warming trend is expected for this week, so a return of freezing temperatures is not expected until at least next week.

Generate This Chart on IEM Website

Strong northwesterly winds are ushering in the coldest air of the season so far with sub-freezing temperatures expected over much of the state Friday night into Saturday morning. Such winds have been noticeably missing this fall season and one of the reasons why temperatures have been so warm for the season to date period. The featured image takes a look into that by plotting wind roses for the 1 September through 14 October period for 2026 (left plot) and the period of record (right plot) over the same period each year. A wind rose is a histogram of wind speed and direction plotted in a polar coordinate. This plot uses a meteorology convention with the bar direction indicating the direction from which the wind is blowing from. A visual comparison between the two plots is very telling with an immediate lack of westerly through northerly winds throughout the 2026 period. Wind from this direction is typically bringing in cooler air, which has been lacking this season. Instead, plenty of southeasterly flow is shown which is typically warmer and more humid.

Generate This Chart on IEM Website

Chilly weather is finally arriving to close out this week with temperatures below freezing expected for some by Friday night into Saturday morning. Up until this upcoming event, chilly weather was practically not existent as shown by the featured chart. The chart presents the accumulated season to date coldest low temperature for Ames. The blue line represents the 2026-2027 cold season with values found near the top or above the historical range. The black line shows the simple period of record average and indicates the average first freezing date is about last week, so Iowa avoided any early frost by a wide margin this year.

Generate This Chart on IEM Website

The past few days have seen numerous record high temperatures either tied or set across the Midwestern US. Cedar Rapids, for example, tied their record high on Monday at 88°F with the previous record set in 1995. The featured map takes a look into the percentage of days with a high temperature record occurring over more than just one year. Rewording, the percentage of days with ties present. This is based on long term climate sites tracked by the NWS. There are some local quirks with some stations having a longer period of record and thus a higher chance of having ties, but the overall spatial trend is rather clear. The moderating effects of higher humidity levels and nearby bodies of water help to tighten the range of possible temperatures and create a higher chance of generating ties. High temperatures are more variable further inland with the lowest frequencies found over the most continental areas of the northern High Plains.

Monday was another very warm October day with a number of locations at or near record high temperatures. With a high of 87°F, Burlington set a new daily record besting the previous record of 86°F set in 1956. The featured chart looks into the year where the present day record lies by day of the year. The dots show the year of the daily record with any ties both plotted. The right side bar charts total up the record counts by decade. The colors represent the age of the record. The upper left panel shows the record daily high temperatures and the lack of recent such records during the summer months is readily apparent. The next panel shows the opposite situation with plenty of record maximum warm low temperatures being recently set over the past few decades and during the summer months. Tuesday will be a bit cooler, but still plenty warm for mid October!

Generate This Chart on IEM Website

The weather is now fully cooperating to help with the fall harvest with plenty of sunshine, very warm temperatures, and a drying breeze. For Sioux City, after setting a record high temperature of 93°F on Saturday, a record high temperature was tied on Sunday at 91°F. The featured chart looks into the frequency of having a two day stretch with a high temperature of at least 91°F over those two days for Sioux City. The right hand side tables list out the end dates of the earliest and latest such two day periods on record. This past weekend comes in second latest behind a two day later event back in 1975. Monday will be another very warm day with record high temperatures again possible.

Generate This Chart on IEM Website