Average Weather in West Lafayette Indiana, United States
In West Lafayette, the temperature typically varies from 20°F to 85°F over the course of the year, and is rarely below 1°F or above 93°F.
The warm season lasts for 125 days, from May 21 to September 23, with an average daily high temperature above 74°F. The hottest day of the year is July 19, with an average high of 85°F and low of 66°F.
The cold season lasts for 91 days, from December 1 to March 2, with an average daily high temperature below 45°F. The coldest day of the year is January 29, with an average low of 20°F and high of 34°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
The length of the day in West Lafayette varies significantly over the course of the year. In 2017, the shortest day is December 21, with 9 hours, 17 minutes of daylight; the longest day is June 21, with 15 hours, 4 minutes of daylight.
Hours of Daylight and Twilight
The earliest sunrise is at 6:16 AM on June 14, and the latest sunrise is 2 hours, 4 minutes later at 8:21 AM on November 4. The earliest sunset is at 5:20 PM on December 7, and the latest sunset is 4 hours, 1 minute later at 9:21 PM on June 27.
Daylight saving time (DST) is observed in West Lafayette during 2017, starting in the spring on March 12, lasting 237 days, and ending in the fall on November 5.
Sunrise & Sunset with Twilight and Daylight Saving Time
In West Lafayette, 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 West Lafayette begins around June 13 and lasts for 140 days, ending around October 31. On August 23, 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 31 and lasts for 225 days, ending around June 13. On December 28, the cloudiest day of the year, the sky is overcast or mostly cloudy 59% of the time, and clear, mostly clear, or partly cloudy 41% of the time.
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. The chance of wet days in West Lafayette varies throughout the year.
The wetter season lasts 162 days, from March 30 to September 8, with a greater than 29% chance of a given day being a wet day. The chance of a wet day peaks at 41% on May 27.
The drier season lasts 203 days, from September 8 to March 30. The smallest chance of a wet day is 17% on February 8.
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 throughout the year is rain alone, with a peak probability of 41% on May 27.
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 in the year. West Lafayette experiences significant seasonal variation in monthly rainfall.
Rain falls throughout the year in West Lafayette. The most rain falls during the 31 days centered around June 8, with an average total accumulation of 4.1 inches.
The least rain falls around January 28, with and average total accumulation of 1.2 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 in the year. West Lafayette experiences some seasonal variation in monthly liquid-equivalent snowfall.
The snowy period of the year lasts for 121 days, from November 25 to March 26, with a sliding 31-day liquid-equivalent snowfall of at least 0.1 inches. The most snow falls during the 31 days centered around February 1, with an average total liquid-equivalent accumulation of 0.4 inches.
The snowless period of the year lasts for 244 days, from March 26 to November 25. The least snow falls around July 15, with an average total liquid-equivalent accumulation of 0.0 inches.
Average Liquid-Equivalent Monthly Snowfall
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.
West Lafayette experiences very significant seasonal variation in the perceived humidity.
The muggier period of the year lasts for 116 days, from May 28 to September 21, 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 21, with muggy conditions 54% of the time.
The least muggy day of the year is February 8, when muggy conditions are essentially unheard of.
Humidity Comfort Levels
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 West Lafayette experiences mildly seasonal variation over the course of the year.
The windier part of the year lasts for 231 days, from October 8 to May 27, with average wind speeds of more than 5.3 miles per hour. The windiest day of the year is April 1, with an average hourly wind speed of 6.8 miles per hour.
The calmer time of year lasts for 134 days, from May 27 to October 8. The calmest day of the year is August 3, with an average hourly wind speed of 3.9 miles per hour.
Average Wind Speed
The predominant average hourly wind direction in West Lafayette varies throughout the year.
The wind is most often from the south for 246 days, from March 30 to December 1, with a peak percentage of 39% on November 13. The wind is most often from the west for 119 days, from December 1 to March 30, with a peak percentage of 42% on January 13.
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 very significant seasonal variation over the course of the year.
The brighter period of the year lasts for 122 days, from April 29 to August 29, with an average daily incident shortwave energy per square meter above 5.8 kWh. The brightest day of the year is July 2, with an average of 6.9 kWh.
The darker period of the year lasts for 98 days, from November 4 to February 10, with an average daily incident shortwave energy per square meter below 2.8 kWh. The darkest day of the year is December 18, with an average of 1.8 kWh.
Average Daily Incident Shortwave Solar Energy
For the purposes of this report, the geographical coordinates of West Lafayette are 40.426 deg latitude, -86.908 deg longitude, and 627 ft elevation (map ).
The topography within 2 miles of West Lafayette contains only modest variations in elevation, with a maximum elevation change of 220 feet, and an average elevation above sea level of 603 feet. Within 10 miles also contains only modest variations in elevation (276 feet). Within 50 miles contains significant variations in elevation (617 feet).
The area within 2 miles of West Lafayette is covered by artificial surfaces (84%), within 10 miles by cropland (70%) and artificial surfaces (16%), and within 50 miles by cropland (90%).
This report illustrates the typical weather in West Lafayette, 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 West Lafayette.
For each station, the records are corrected for the elevation difference between that station and West Lafayette 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 West Lafayette is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between West Lafayette and a given station.
The stations contributing to this reconstruction are: Purdue University Airport (96%, 2.9 kilometers, southwest), Jasper County Airport (1.7%, 45 kilometers, north), Logansport Cass County Airport (1.2%, 55 kilometers, northeast), and Indianapolis Executive Airport (0.8%, 71 kilometers, southeast).
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 .