The IEM produces a NWS COOP valued added dataset that contains estimated values when a NWS COOP site values to report one day. There's also a lot more to it than just that, but the purpose is to provide a complete time series without missing values.

In some instances, these virtual sites tracked NWS COOP sites that only reported temperature or precipitation, but not both. I've made a change now to no longer track these sites as "real-time", meaning these sites are no longer available with up-to-today data. This change removed 1,268 such sites. There are still 5,466 real-time sites available via the IEM, so take heart!

As a general comment, significant improvements were made to this workflow/dataset over the course of 2021 with smaller variances now against similar datasets provided by ACIS. Feedback and variance reports on this dataset are always welcome!

The Climodat section of the IEM website has been around since the beginning and dates further back than that. It generates a series of simple ASCII text reports that address commonly asked questions of long term daily data.

The input dataset used for these reports has been curated over many decades by climatologists here at ISU. Generally, this dataset only covered locations in Iowa. Over the years, the IEM expanded this dataset to cover the upper Midwestern US and now it covers the Continental US. Please note that there no longer is any manual data quality control done by ISU climatologists on this dataset. Previously, the Iowa data would go through a delayed quality control process by the State of Iowa Climatologist.

The realtime daily data closely tracks the NWS Cooperative Observer (COOP) network and Automated Surface Observation Station (ASOS) sites. This dataset should closely resemble datasets made available by the National Centers for Environmental Information (NCEI) and by NOAA's Regional Climate Centers (see ACIS).

In general, the IEM does not attempt to generate redundant datasets made available elsewhere. The most obvious redundancy here is to what is found within ACIS. Here's a current list of why this dataset continues to be redundantly generated here:

1. Solar Radiation is an often requested dataset and while the NWS COOP nor ASOS network observe this variable, the IEM does processing to have model estimated solar radiation data tag along and made available for download. It is an useful value-add.
2. The climodat work done by the IEM dates back to the beginning of the IEM and even before that, the recent services from NCEI and ACIS are relatively new. It would be nice to see some more products and rough edges taken out of upstream services before redirecting folks there.
3. A lot of IEM infrastructure relies on this dataset. While a straight usage of ACIS would be possible, we would need to still have code in place to handle any ACIS outages or missing data. The IEM climodat dataset always contains at least 'daily' high and low temperature along with precipitation. Observations are prioritized, but estimates are done when necessary.
4. The IEM has a very extensive ingest of NWS COOP data in SHEF format. With this data in house, it makes sense to continue curating the long term record.

Long term, the hope is to point folks upstream to NOAA when they want the data and reports, but in the interim, the IEM continues to effort removing variances between this dataset and other online sources. As always, feedback and comments are welcome.

The quality controlled Iowa COOP data for July 2013 has been uploaded to the IEM. These observations are kindly provided by Harry Hillaker, our state climatologist, who passes along these notes on the month:

General Summary. Iowa temperatures averaged 72.4° or 1.2° below normal while precipitation totaled 1.76 inches or 2.74 inches less than normal. This ranks as the 30th coolest and 8th driest July among 141 years of state records.

Temperatures. The month began with four days of below normal temperatures with Atlantic and Chariton recording morning lows of 48° on the 1st. This was followed by five days of above normal readings topped off by 95° maximums on the 8th at Clarion, Hampton and Pocahontas. The remainder of the month was evenly divided between one long warm spell (14th-22nd) and an equally long cool spell (23rd-31st). The month's highest temperature was a 98° reading at Keokuk on the 19th while heat indices (the estimated 'feel' of the air by combining temperature and humidity) maxed out at 102° at Monticello on the 17th and Des Moines, Iowa City and Knoxville on the 19th. The last nine days of the month all averaged cooler than usual with particularly cool weather from the 27th to the 29th. Battle Creek in Ida County reported a morning low of 39° on the 27th while Cresco saw an afternoon high of only 58° the same day. Battle Creek's low represented the first occurrence of sub-40° weather in July in Iowa since July 7, 1984. Daily record low temperatures were set over most of Iowa on the 28th and over portions of the state on the 27th and 29th.

Cooling Degree Day Totals. Home air conditioning requirements, as estimated by cooling degree day totals, averaged 45% less than last July and 8% less than normal. Degree day totals so far this cooling season are running 41% less than last year at this time and 3% less than normal.

Precipitation. The big weather story of the month was precipitation, or the lack of it. Following seven consecutive months of above normal precipitation July turned very dry. There were a few small areas in north central and south central Iowa receiving above normal rainfall but most of the southwest one-half of the state was very dry. Rain totals for the month varied from 0.13 inches at Atlantic to 6.72 inches at Lake Mills. Record low July precipitation totals were recorded at:

City	July 2013	Old July Record	Period of Record
Carroll	0.18 inches	0.23 inches in 1947	127 years
Sac City	0.20 inches	0.35 inches in 1901	137 years
Red Oak	0.42 inches	0.46 inches in 1959	102 years

Atlantic's total was the second lowest for July at that location with just a trace recorded in 2012.

The following is the number of new daily records set at COOP sites based on data back to 1951.

                 ____________2013_________________________2012___
                 JUL  JUN  MAY  APR  MAR  FEB  JAN  DEC  NOV  OCT
Maximum High:     13   43  169   28    0    0  157   87  152   14
Minimum High:    204   97  311  358    9   10   20    2    0   61
Maximum Low:      58   50   61   28    0    1   79   33   61  104
Minimum Low:     217   53  116  319   35    0    0    0    0   87
Maximum Precip:   51  103  302  226   74   82   93   91   40   99

The following is some bulk statistics on how well IEM's daily COOP data estimator is performing on a monthly basis versus this QC'd dataset.

                 ______2013______________________________2012_
                 JUL   JUN   MAY   APR   MAR   FEB   JAN   DEC
High Temp Bias   0.4   0.4   0.1   1.3   0.8   1.0   1.0   0.3
High Temp RMSE   0.9   0.8   0.8   1.6   1.1   1.3   1.4   0.8
Low  Temp Bias   0.8   1.2   1.2   2.5   2.2   2.5   1.8   1.3
Low  Temp RMSE   1.3   1.4   1.5   2.6   2.3   2.6   2.1   1.8
Precip    Bias  -0.08 -0.39 -0.87 -0.56 -0.14  0.01 -0.07 -0.39
Precip    RMSE   0.53  0.94  1.28  0.91  0.42  0.35  0.24  0.42

The quality controlled Iowa COOP data for June 2013 has been uploaded to the IEM. These observations are kindly provided by Harry Hillaker, our state climatologist, who passes along these notes on the month:

General Summary. Iowa temperatures averaged 69.0° or 0.7° below normal while precipitation totaled 5.01 inches or 0.01 inches below normal. This ranks as the 55th coolest and 61st wettest June among 141 years of records. A cooler June has not been recorded since 2004.

Temperatures. The very cool spring weather pattern continued into the first ten days of June with temperatures averaging below normal each day. Elkader reported a low of 37° on the morning of the 3rd for Iowa's lowest temperature for so late in the season since 1998. The month's first 80 degree maximum temperature did not arrive until the 10th. However, only five of the remaining days of June averaged cooler than normal. Nevertheless, extreme heat was absent during the month with monthly maximum temperatures of only 94° recorded at Sioux City on the 21st and Muscatine on the 22nd. A lower statewide maximum temperature in June has been recorded only six times in the past century (most recently in 2008 at 92°).

Cooling Degree Days Totals. Home air conditioning requirements, as estimated by cooling degree day totals, averaged 1% less than normal and 25% less than last June. Thus far this season cooling degree day totals are running 2% greater than normal and 36% less than at this time last year.

Precipitation. The storm track shifted a bit further north in June, keeping the excessive rains confined to about the northeast one-third of the state. The month's largest event came from the 21st to the 23rd with Dorchester recording 8.99 inches of rain. Major flooding resulted along northeast Iowa rivers such as the Upper Iowa and the Turkey. A second major rain event on the 24th brought 6.80 inches of rain to Lowden and resulted in major flooding along the Wapsipinicon River. Rain totals for the month varied from 2.11 inches at Holly Springs (Woodbury County) and 2.22 inches near Albia to a whopping 14.48 inch total at Dorchester (but still shy of their June record total of 15.13 inches set in 2008). The persistent spring and early summer precipitation has allowed all of Iowa to be rated as drought-free by the U. S. Drought Monitor for the first time since early August 2011. According to Iowa Agricultural Statistics crop planting progress has been the slowest since 1993 with 4% of the soybean acreage, mostly in north central and northeast Iowa, still unplanted at month's end. The statewide average year-to-date precipitation total was a record for the first one-half of the year at 24.87 inches or 7.67 inches more than normal. The old record for January through June was 24.46 inches set in 2008 while 2012's total for the entire year was 26.54 inches.

Severe Weather. June was a more active month for severe weather in Iowa than earlier months this year, but still quieter than what is typical. The two largest events came on the 12th and 24th. Hail, high winds and tornadoes were reported across north central and northeast Iowa on the 12th with an EF-3 tornado touching down near Belmond. More widespread activity occurred on the 24th when high winds struck a wide area from southwest into central Iowa with a second area from south central to east central Iowa. Within the latter area an EF-1 tornado resulted in one fatality at Muscatine.

The following is the number of new daily records set at COOP sites based on data back to 1951.

                 _____2013_________________________2012__________
                 JUN  MAY  APR  MAR  FEB  JAN  DEC  NOV  OCT  SEP
Maximum High:     43  169   28    0    0  157   87  152   14   69
Minimum High:     97  311  358    9   10   20    2    0   61    7
Maximum Low:      50   61   28    0    1   79   33   61  104    3
Minimum Low:      53  116  319   35    0    0    0    0   87   57
Maximum Precip:  103  302  226   74   82   93   91   40   99   10

The following is some bulk statistics on how well IEM's daily COOP data estimator is performing on a monthly basis versus this QC'd dataset.

                 ______2013______________________________2012_
                 JUN   MAY   APR   MAR   FEB   JAN   DEC   NOV
High Temp Bias   0.4   0.1   1.3   0.8   1.0   1.0   0.3   1.0
High Temp RMSE   0.8   0.8   1.6   1.1   1.3   1.4   0.8   1.2
Low  Temp Bias   1.2   1.2   2.5   2.2   2.5   1.8   1.3   1.4
Low  Temp RMSE   1.4   1.5   2.6   2.3   2.6   2.1   1.8   1.9
Precip    Bias  -0.39 -0.87 -0.56 -0.14  0.01 -0.07 -0.39 -0.07
Precip    RMSE   0.94  1.28  0.91  0.42  0.35  0.24  0.42  0.19