1. WeatherSpark.com
  2. United States
  3. Iowa
  4. Oelwein

Average Weather in Oelwein Iowa, United States

In Oelwein, the summers are long, warm, and wet; the winters are freezing, dry, and windy; and it is partly cloudy year round. Over the course of the year, the temperature typically varies from 12°F to 83°F and is rarely below -9°F or above 91°F.

Climate Summary

freezingcoldcoolwarmcoolcoldJanFebMarAprMayJunJulAugSepOctNovDec69%69%42%42%clearovercastprecipitation: 4.5 inprecipitation: 4.5 in0.7 in0.7 inmuggy: 47%muggy: 47%0%0%drydrytourism score: 6.6tourism score: 6.60.00.0
Click on each chart for more information.

Based on the tourism score, the best time of year to visit Oelwein for warm-weather activities is from mid June to early September.

Temperature

The warm season lasts for 4.2 months, from May 16 to September 22, with an average daily high temperature above 72°F. The hottest day of the year is July 18, with an average high of 83°F and low of 64°F.

The cold season lasts for 3.2 months, from November 29 to March 3, with an average daily high temperature below 38°F. The coldest day of the year is January 22, with an average low of 12°F and high of 27°F.

Average High and Low Temperature

The daily average high (red line) and low (blue line) temperature, with 25th to 75th and 10th to 90th percentile bands. The thin dotted lines are the corresponding average perceived temperatures.

The figure below shows you a compact characterization of the entire year of hourly average temperatures. The horizontal axis is the day of the year, the vertical axis is the hour of the day, and the color is the average temperature for that hour and day.

Average Hourly Temperature

Average Hourly Temperature in OelweinJanFebMarAprMayJunJulAugSepOctNovDec12 AM4 AM8 AM12 PM4 PM8 PM12 AMfreezingfreezingcoldcoldcoolcomfortablecomfortablewarmvery coldvery cold
The average hourly temperature, color coded into bands: frigid < 15°F < freezing < 32°F < very cold < 45°F < cold < 55°F < cool < 65°F < comfortable < 75°F < warm < 85°F < hot < 95°F < sweltering. The shaded overlays indicate night and civil twilight.

Almaty, Kazakhstan (6,467 miles away) is the far-away foreign place with temperatures most similar to Oelwein (view comparison).

Clouds

In Oelwein, the average percentage of the sky covered by clouds experiences significant seasonal variation over the course of the year.

The clearer part of the year in Oelwein begins around June 6 and lasts for 4.6 months, ending around October 26. On July 28, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 69% of the time, and overcast or mostly cloudy 31% of the time.

The cloudier part of the year begins around October 26 and lasts for 7.4 months, ending around June 6. On February 6, the cloudiest day of the year, the sky is overcast or mostly cloudy 58% of the time, and clear, mostly clear, or partly cloudy 42% of the time.

Cloud Cover Categories

Cloud Cover Categories in OelweinclearercloudiercloudierJanFebMarAprMayJunJulAugSepOctNovDec0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%Jul 2869%Jul 2869%Feb 642%Feb 642%Jun 655%Jun 655%Oct 2656%Oct 2656%clearmostly clearpartly cloudymostly cloudyovercast
The percentage of time spent in each cloud cover band, categorized by the percentage of the sky covered by clouds: clear < 20% < mostly clear < 40% < partly cloudy < 60% < mostly cloudy < 80% < overcast.

Precipitation

A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. The chance of wet days in Oelwein varies significantly throughout the year.

The wetter season lasts 6.0 months, from April 5 to October 3, with a greater than 27% chance of a given day being a wet day. The chance of a wet day peaks at 42% on June 10.

The drier season lasts 6.0 months, from October 3 to April 5. The smallest chance of a wet day is 11% on January 22.

Among wet days, we distinguish between those that experience rain alone, snow alone, or a mixture of the two. Based on this categorization, the most common form of precipitation in Oelwein changes throughout the year.

Rain alone is the most common for 9.6 months, from February 21 to December 11. The highest chance of a day with rain alone is 42% on June 10.

Snow alone is the most common for 2.4 months, from December 11 to February 21. The highest chance of a day with snow alone is 8% on January 10.

Daily Chance of Precipitation

Daily Chance of Precipitation in OelweinsnowrainJanFebMarAprMayJunJulAugSepOctNovDec0%10%20%30%40%50%60%70%80%90%100%Jun 1042%Jun 1042%Jan 2211%Jan 2211%Feb 2114%Feb 2114%Dec 1117%Dec 1117%Apr 527%Apr 527%Oct 327%Oct 327%snowrainmixed
The percentage of days in which various types of precipitation are observed, excluding trace quantities: rain alone, snow alone, and mixed (both rain and snow fell in the same day).

Rainfall

To show variation within the months and not just the monthly totals, we show the rainfall accumulated over a sliding 31-day period centered around each day of the year. Oelwein experiences extreme seasonal variation in monthly rainfall.

The rainy period of the year lasts for 10 months, from February 15 to December 25, with a sliding 31-day rainfall of at least 0.5 inches. The most rain falls during the 31 days centered around June 18, with an average total accumulation of 4.5 inches.

The rainless period of the year lasts for 1.7 months, from December 25 to February 15. The least rain falls around January 21, with an average total accumulation of 0.2 inches.

Average Monthly Rainfall

The average rainfall (solid line) accumulated over the course of a sliding 31-day period centered on the day in question, with 25th to 75th and 10th to 90th percentile bands. The thin dotted line is the corresponding average liquid-equivalent snowfall.

Snowfall

We report snowfall in liquid-equivalent terms. The actual depth of new snowfall is typically between 5 and 10 times the liquid-equivalent amount, assuming the ground is frozen. Colder, drier snow tends to be on the higher end of that range and warmer, wetter snow on the lower end.

As with rainfall, we consider the snowfall accumulated over a sliding 31-day period centered around each day of the year. Oelwein experiences some seasonal variation in monthly liquid-equivalent snowfall.

The snowy period of the year lasts for 4.8 months, from November 5 to March 31, with a sliding 31-day liquid-equivalent snowfall of at least 0.1 inches. The most snow falls during the 31 days centered around December 20, with an average total liquid-equivalent accumulation of 0.5 inches.

The snowless period of the year lasts for 7.2 months, from March 31 to November 5. The least snow falls around July 27, with an average total liquid-equivalent accumulation of 0.0 inches.

Average Liquid-Equivalent Monthly Snowfall

Average Liquid-Equivalent Monthly Snowfall in OelweinsnowsnowJanFebMarAprMayJunJulAugSepOctNovDec0 in1 in2 in3 in4 in5 inDec 200.5 inDec 200.5 inJul 270.0 inJul 270.0 inNov 50.1 inNov 50.1 inMar 310.1 inMar 310.1 in
The average liquid-equivalent snowfall (solid line) accumulated over the course of a sliding 31-day period centered on the day in question, with 25th to 75th and 10th to 90th percentile bands. The thin dotted line is the corresponding average rainfall.

Sun

The length of the day in Oelwein varies significantly over the course of the year. In 2018, the shortest day is December 21, with 9 hours, 2 minutes of daylight; the longest day is June 21, with 15 hours, 19 minutes of daylight.

Hours of Daylight and Twilight

The number of hours during which the Sun is visible (black line). From bottom (most yellow) to top (most gray), the color bands indicate: full daylight, twilight (civil, nautical, and astronomical), and full night.

The earliest sunrise is at 5:29 AM on June 15, and the latest sunrise is 2 hours, 15 minutes later at 7:44 AM on November 3. The earliest sunset is at 4:33 PM on December 9, and the latest sunset is 4 hours, 16 minutes later at 8:49 PM on June 27.

Daylight saving time (DST) is observed in Oelwein during 2018, starting in the spring on March 11, lasting 7.8 months, and ending in the fall on November 4.

Sunrise & Sunset with Twilight and Daylight Saving Time

Sunrise & Sunset with Twilight and Daylight Saving Time in OelweinJanFebMarAprMayJunJulAugSepOctNovDec12 AM2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AMJun 155:29 AMJun 155:29 AM8:49 PMJun 278:49 PMJun 27Dec 94:33 PMDec 94:33 PM7:44 AMNov 37:44 AMNov 3Mar 11DSTMar 11DSTDSTNov 4DSTNov 4daynightnightnightnightSolarMidnightSolarMidnightSolarNoonSunriseSunset
The solar day over the course of the year 2018. From bottom to top, the black lines are the previous solar midnight, sunrise, solar noon, sunset, and the next solar midnight. The day, twilights (civil, nautical, and astronomical), and night are indicated by the color bands from yellow to gray. The transitions to and from daylight saving time are indicated by the 'DST' labels.

Humidity

We base the humidity comfort level on the dew point, as it determines whether perspiration will evaporate from the skin, thereby cooling the body. Lower dew points feel drier and higher dew points feel more humid. Unlike temperature, which typically varies significantly between night and day, dew point tends to change more slowly, so while the temperature may drop at night, a muggy day is typically followed by a muggy night.

Oelwein experiences significant seasonal variation in the perceived humidity.

The muggier period of the year lasts for 3.4 months, from June 5 to September 17, during which time the comfort level is muggy, oppressive, or miserable at least 12% of the time. The muggiest day of the year is July 23, with muggy conditions 47% of the time.

The least muggy day of the year is February 13, when muggy conditions are essentially unheard of.

Humidity Comfort Levels

Humidity Comfort Levels in OelweinmuggyJanFebMarAprMayJunJulAugSepOctNovDec0%10%20%30%40%50%60%70%80%90%100%Feb 130%Feb 130%Jul 2347%Jul 2347%Jun 512%Jun 512%Sep 1712%Sep 1712%muggymuggydrydryoppressiveoppressivehumidhumidcomfortablecomfortablemiserablemiserable
The percentage of time spent at various humidity comfort levels, categorized by dew point: dry < 55°F < comfortable < 60°F < humid < 65°F < muggy < 70°F < oppressive < 75°F < miserable.

Wind

This section discusses the wide-area hourly average wind vector (speed and direction) at 10 meters above the ground. The wind experienced at any given location is highly dependent on local topography and other factors, and instantaneous wind speed and direction vary more widely than hourly averages.

The average hourly wind speed in Oelwein experiences significant seasonal variation over the course of the year.

The windier part of the year lasts for 7.9 months, from September 30 to May 26, with average wind speeds of more than 10.3 miles per hour. The windiest day of the year is March 23, with an average hourly wind speed of 12.8 miles per hour.

The calmer time of year lasts for 4.1 months, from May 26 to September 30. The calmest day of the year is August 3, with an average hourly wind speed of 7.9 miles per hour.

Average Wind Speed

Average Wind Speed in OelweinwindywindyJanFebMarAprMayJunJulAugSepOctNovDec0 mph2 mph4 mph6 mph8 mph10 mph12 mph14 mph16 mph18 mph20 mphMar 2312.8 mphMar 2312.8 mphAug 37.9 mphAug 37.9 mphSep 3010.3 mphSep 3010.3 mphMay 2610.3 mphMay 2610.3 mph
The average of mean hourly wind speeds (dark gray line), with 25th to 75th and 10th to 90th percentile bands.

The predominant average hourly wind direction in Oelwein varies throughout the year.

The wind is most often from the north for 3.6 months, from January 6 to April 23, with a peak percentage of 35% on March 8. The wind is most often from the south for 7.3 months, from April 23 to December 1, with a peak percentage of 41% on September 5. The wind is most often from the west for 1.2 months, from December 1 to January 6, with a peak percentage of 32% on January 1.

Wind Direction

Wind Direction in OelweinNSWJanFebMarAprMayJunJulAugSepOctNovDec0%100%20%80%40%60%60%40%80%20%100%0%westsouthnortheast
The percentage of hours in which the mean wind direction is from each of the four cardinal wind directions (north, east, south, and west), excluding hours in which the mean wind speed is less than 1 mph. The lightly tinted areas at the boundaries are the percentage of hours spent in the implied intermediate directions (northeast, southeast, southwest, and northwest).

Best Time of Year to Visit

To characterize how pleasant the weather is in Oelwein throughout the year, we compute two travel scores.

The tourism score favors clear, rainless days with perceived temperatures between 65°F and 80°F. Based on this score, the best time of year to visit Oelwein for general outdoor tourist activities is from mid June to early September, with a peak score in the last week of July.

Tourism Score

Tourism Score in Oelweinbest timeJanFebMarAprMayJunJulAugSepOctNovDec02468106.66.60.00.0 precipitationprecipitationcloudscloudstemperaturetemperaturetourism score
The tourism score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).

The beach/pool score favors clear, rainless days with perceived temperatures between 75°F and 90°F. Based on this score, the best time of year to visit Oelwein for hot-weather activities is from late June to mid August, with a peak score in the third week of July.

Beach/Pool Score

Beach/Pool Score in Oelweinbest timeJanFebMarAprMayJunJulAugSepOctNovDec02468105.15.10.00.0 precipitationprecipitationcloudscloudstemperaturetemperaturebeach/pool score
The beach/pool score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).

Methodology

For each hour between 8:00 AM and 9:00 PM of each day in the analysis period (1980 to 2016), independent scores are computed for perceived temperature, cloud cover, and total precipitation. Those scores are combined into a single hourly composite score, which is then aggregated into days, averaged over all the years in the analysis period, and smoothed.

Our cloud cover score is 10 for fully clear skies, falling linearly to 9 for mostly clear skies, and to 1 for fully overcast skies.

Our precipitation score, which is based on the three-hour precipitation centered on the hour in question, is 10 for no precipitation, falling linearly to 9 for trace precipitation, and to 0 for 0.04 inches of precipitation or more.

Our tourism temperature score is 0 for perceived temperatures below 50°F, rising linearly to 9 for 65°F, to 10 for 75°F, falling linearly to 9 for 80°F, and to 1 for 90°F or hotter.

Our beach/pool temperature score is 0 for perceived temperatures below 65°F, rising linearly to 9 for 75°F, to 10 for 82°F, falling linearly to 9 for 90°F, and to 1 for 100°F or hotter.

Growing Season

Definitions of the growing season vary throughout the world, but for the purposes of this report, we define it as the longest continuous period of non-freezing temperatures (≥ 32°F) in the year (the calendar year in the Northern Hemisphere, or from July 1 until June 30 in the Southern Hemisphere).

The growing season in Oelwein typically lasts for 5.6 months (171 days), from around April 20 to around October 8, rarely starting before April 3 or after May 7, and rarely ending before September 20 or after October 28.

Time Spent in Various Temperature Bands and the Growing Season

Time Spent in Various Temperature Bands and the Growing Season in Oelweingrowing seasonJanFebMarAprMayJunJulAugSepOctNovDec0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%Apr 2050%Apr 2050%Oct 850%Oct 850%May 790%May 790%Sep 2090%Sep 2090%Apr 310%Apr 310%Oct 2810%Oct 2810%Jul 12100%Jul 12100%frigidfreezingvery coldcoolcomfortablewarmhotcold
The percentage of time spent in various temperature bands: frigid < 15°F < freezing < 32°F < very cold < 45°F < cold < 55°F < cool < 65°F < comfortable < 75°F < warm < 85°F < hot < 95°F < sweltering. The black line is the percentage chance that a given day is within the growing season.

Growing degree days are a measure of yearly heat accumulation used to predict plant and animal development, and defined as the integral of warmth above a base temperature, discarding any excess above a maximum temperature. In this report, we use a base of 50°F and a cap of 86°F.

Based on growing degree days alone, the first spring blooms in Oelwein should appear around April 17, only rarely appearing before April 6 or after May 2.

Growing Degree Days

The average growing degree days accumulated over the course of the year, with 25th to 75th and 10th to 90th percentile bands.

Solar Energy

This section discusses the total daily incident shortwave solar energy reaching the surface of the ground over a wide area, taking full account of seasonal variations in the length of the day, the elevation of the Sun above the horizon, and absorption by clouds and other atmospheric constituents. Shortwave radiation includes visible light and ultraviolet radiation.

The average daily incident shortwave solar energy experiences extreme seasonal variation over the course of the year.

The brighter period of the year lasts for 3.5 months, from May 5 to August 22, with an average daily incident shortwave energy per square meter above 5.9 kWh. The brightest day of the year is July 1, with an average of 7.0 kWh.

The darker period of the year lasts for 3.4 months, from October 31 to February 10, with an average daily incident shortwave energy per square meter below 2.7 kWh. The darkest day of the year is December 22, with an average of 1.7 kWh.

Average Daily Incident Shortwave Solar Energy

The average daily shortwave solar energy reaching the ground per square meter (orange line), with 25th to 75th and 10th to 90th percentile bands.

Topography

For the purposes of this report, the geographical coordinates of Oelwein are 42.673 deg latitude, -91.913 deg longitude, and 1,056 ft elevation.

The topography within 2 miles of Oelwein contains only modest variations in elevation, with a maximum elevation change of 164 feet and an average elevation above sea level of 1,062 feet. Within 10 miles also contains only modest variations in elevation (292 feet). Within 50 miles contains only modest variations in elevation (738 feet).

The area within 2 miles of Oelwein is covered by cropland (83%) and artificial surfaces (17%), within 10 miles by cropland (99%), and within 50 miles by cropland (89%).

Data Sources

This report illustrates the typical weather in Oelwein, based on a statistical analysis of historical hourly weather reports and model reconstructions from January 1, 1980 to December 31, 2016.

Temperature and Dew Point

There are 4 weather stations near enough to contribute to our estimation of the temperature and dew point in Oelwein.

For each station, the records are corrected for the elevation difference between that station and Oelwein according to the International Standard Atmosphere , and by the relative change present in the MERRA-2 satellite-era reanalysis between the two locations.

The estimated value at Oelwein is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Oelwein and a given station.

The stations contributing to this reconstruction are: Oelwein Municipal Airport (89%, 5.0 kilometers, west); Independence Municipal Airport (8%, 25 kilometers, south); Decorah Municipal Airport (1.8%, 68 kilometers, north); and Prairie du Chien Municipal Airport (1.5%, 75 kilometers, northeast).

Other Data

All data relating to the Sun's position (e.g., sunrise and sunset) are computed using astronomical formulas from the book, Astronomical Tables of the Sun, Moon and Planets , by Jean Meeus.

All other weather data, including cloud cover, precipitation, wind speed and direction, and solar flux, come from NASA's MERRA-2 Modern-Era Retrospective Analysis . This reanalysis combines a variety of wide-area measurements in a state-of-the-art global meteorological model to reconstruct the hourly history of weather throughout the world on a 50-kilometer grid.

Land Use data comes from the Global Land Cover SHARE database , published by the Food and Agriculture Organization of the United Nations.

Elevation data comes from the Shuttle Radar Topography Mission (SRTM) , published by NASA's Jet Propulsion Laboratory.

Names, locations, and time zones of places and some airports come from the GeoNames Geographical Database .

Time zones for aiports and weather stations are provided by AskGeo.com .

Maps are © Esri, with data from National Geographic, Esri, DeLorme, NAVTEQ, UNEP-WCMC, USGS, NASA, ESA, METI, NRCAN, GEBCO, NOAA, and iPC.

Disclaimer

The information on this site is provided as is, without any assurances as to its accuracy or suitability for any purpose. Weather data is prone to errors, outages, and other defects. We assume no responsibility for any decisions made on the basis of the content presented on this site.

We draw particular cautious attention to our reliance on the MERRA-2 model-based reconstructions for a number of important data series. While having the tremendous advantages of temporal and spatial completeness, these reconstructions: (1) are based on computer models that may have model-based errors, (2) are coarsely sampled on a 50 km grid and are therefore unable to reconstruct the local variations of many microclimates, and (3) have particular difficulty with the weather in some coastal areas, especially small islands.

We further caution that our travel scores are only as good as the data that underpin them, that weather conditions at any given location and time are unpredictable and variable, and that the definition of the scores reflects a particular set of preferences that may not agree with those of any particular reader.