Average Weather in Earlham Iowa, United States
In Earlham, the summers are long, warm, humid, 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 16°F to 85°F and is rarely below -4°F or above 94°F.
Based on the tourism score, the best time of year to visit Earlham for warm-weather activities is from early June to mid September.
The hot season lasts for 3.9 months, from May 23 to September 20, with an average daily high temperature above 75°F. The hottest day of the year is July 20, with an average high of 85°F and low of 67°F.
The cold season lasts for 3.1 months, from November 28 to March 1, with an average daily high temperature below 43°F. The coldest day of the year is January 21, with an average low of 16°F and high of 32°F.
Average High and Low Temperature
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
In Earlham, 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 Earlham begins around June 9 and lasts for 4.5 months, ending around October 25. On August 26, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 71% of the time, and overcast or mostly cloudy 29% of the time.
The cloudier part of the year begins around October 25 and lasts for 7.5 months, ending around June 9. On February 13, the cloudiest day of the year, the sky is overcast or mostly cloudy 54% of the time, and clear, mostly clear, or partly cloudy 46% of the time.
Cloud Cover Categories
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. The chance of wet days in Earlham varies significantly throughout the year.
The wetter season lasts 5.7 months, from April 5 to September 26, with a greater than 26% chance of a given day being a wet day. The chance of a wet day peaks at 43% on June 7.
The drier season lasts 6.3 months, from September 26 to April 5. The smallest chance of a wet day is 8% on January 9.
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 Earlham changes throughout the year.
Rain alone is the most common for 10 months, from February 15 to December 19. The highest chance of a day with rain alone is 43% on June 7.
Snow alone is the most common for 1.9 months, from December 19 to February 15. The highest chance of a day with snow alone is 6% on January 25.
Daily Chance of Precipitation
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. Earlham experiences extreme seasonal variation in monthly rainfall.
The rainy period of the year lasts for 10 months, from February 17 to December 23, with a sliding 31-day rainfall of at least 0.5 inches. The most rain falls during the 31 days centered around June 14, with an average total accumulation of 4.5 inches.
The rainless period of the year lasts for 1.8 months, from December 23 to February 17. The least rain falls around January 21, with an average total accumulation of 0.2 inches.
Average Monthly Rainfall
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. Earlham experiences some seasonal variation in monthly liquid-equivalent snowfall.
The snowy period of the year lasts for 4.5 months, from November 10 to March 27, 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 17, with an average total liquid-equivalent accumulation of 0.4 inches.
The snowless period of the year lasts for 7.4 months, from March 27 to November 10. The least snow falls around July 13, with an average total liquid-equivalent accumulation of 0.0 inches.
Average Liquid-Equivalent Monthly Snowfall
The length of the day in Earlham varies significantly over the course of the year. In 2018, the shortest day is December 21, with 9 hours, 10 minutes of daylight; the longest day is June 21, with 15 hours, 11 minutes of daylight.
Hours of Daylight and Twilight
The earliest sunrise is at 5:42 AM on June 14, and the latest sunrise is 2 hours, 9 minutes later at 7:50 AM on November 3. The earliest sunset is at 4:46 PM on December 7, and the latest sunset is 4 hours, 8 minutes later at 8:54 PM on June 27.
Daylight saving time (DST) is observed in Earlham 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
Earlham experiences extreme seasonal variation in the perceived humidity.
The muggier period of the year lasts for 3.5 months, from June 2 to September 17, during which time the comfort level is muggy, oppressive, or miserable at least 14% of the time. The muggiest day of the year is July 22, with muggy conditions 56% of the time.
The least muggy day of the year is February 11, when muggy conditions are essentially unheard of.
Humidity Comfort Levels
The average hourly wind speed in Earlham experiences significant seasonal variation over the course of the year.
The windier part of the year lasts for 8.0 months, from September 28 to May 27, with average wind speeds of more than 10.5 miles per hour. The windiest day of the year is April 1, with an average hourly wind speed of 12.9 miles per hour.
The calmer time of year lasts for 4.0 months, from May 27 to September 28. The calmest day of the year is August 3, with an average hourly wind speed of 8.2 miles per hour.
Average Wind Speed
The predominant average hourly wind direction in Earlham varies throughout the year.
The wind is most often from the north for 3.6 months, from January 1 to April 20, with a peak percentage of 35% on March 8. The wind is most often from the south for 7.4 months, from April 20 to December 1, with a peak percentage of 46% on September 5. The wind is most often from the west for 1.0 months, from December 1 to January 1, with a peak percentage of 33% on December 30.
Best Time of Year to Visit
To characterize how pleasant the weather is in Earlham 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 Earlham for general outdoor tourist activities is from early June to mid September, with a peak score in the last week of August.
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 Earlham for hot-weather activities is from late June to mid August, with a peak score in the third week of July.
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.
The growing season in Earlham typically lasts for 5.9 months (179 days), from around April 17 to around October 13, rarely starting before March 30 or after May 5, and rarely ending before September 24 or after November 1.
Time Spent in Various Temperature Bands and the Growing Season
Based on growing degree days alone, the first spring blooms in Earlham should appear around April 7, only rarely appearing before March 26 or after April 25.
Growing Degree Days
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 3.6 months, from May 3 to August 23, with an average daily incident shortwave energy per square meter above 6.0 kWh. The brightest day of the year is July 4, with an average of 7.0 kWh.
The darker period of the year lasts for 3.2 months, from November 2 to February 10, with an average daily incident shortwave energy per square meter below 2.9 kWh. The darkest day of the year is December 21, with an average of 1.8 kWh.
Average Daily Incident Shortwave Solar Energy
For the purposes of this report, the geographical coordinates of Earlham are 41.492 deg latitude, -94.124 deg longitude, and 1,076 ft elevation.
The topography within 2 miles of Earlham contains only modest variations in elevation, with a maximum elevation change of 171 feet and an average elevation above sea level of 1,076 feet. Within 10 miles also contains only modest variations in elevation (384 feet). Within 50 miles contains only modest variations in elevation (830 feet).
The area within 2 miles of Earlham is covered by cropland (99%), within 10 miles by cropland (92%), and within 50 miles by cropland (89%).
This report illustrates the typical weather in Earlham, 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 6 weather stations near enough to contribute to our estimation of the temperature and dew point in Earlham.
For each station, the records are corrected for the elevation difference between that station and Earlham 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 Earlham is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Earlham and a given station.
The stations contributing to this reconstruction are: Perry Municipal Airport (27%, 38 kilometers, north); Des Moines International Airport (25%, 40 kilometers, east); Creston Municipal Airport (14%, 58 kilometers, south); Osceola Municipal Airport (13%, 61 kilometers, southeast); Audubon County Airport (11%, 70 kilometers, west); and Atlantic Municipal Airport (9%, 78 kilometers, west).
Time zones for aiports and weather stations are provided by AskGeo.com .