Average Weather at Grissom Air Force Base / Peru Indiana, United States
At Grissom Air Force Base / Peru, the summers are long, warm, humid, and wet; the winters are freezing and windy; and it is partly cloudy year round. Over the course of the year, the temperature typically varies from 19°F to 84°F and is rarely below 1°F or above 92°F.
Based on the tourism score, the best time of year to visit Grissom Air Force Base / Peru for warm-weather activities is from mid June to mid September.
The warm season lasts for 4.0 months, from May 22 to September 22, with an average daily high temperature above 74°F. The hottest day of the year is July 19, with an average high of 84°F and low of 66°F.
The cold season lasts for 3.0 months, from December 1 to March 2, with an average daily high temperature below 43°F. The coldest day of the year is January 29, with an average low of 19°F and high of 33°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
At Grissom Air Force Base / Peru, 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 at Grissom Air Force Base / Peru begins around June 11 and lasts for 4.6 months, 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 7.4 months, ending around June 11. On December 29, the cloudiest day of the year, the sky is overcast or mostly cloudy 61% of the time, and clear, mostly clear, or partly cloudy 39% 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 at Grissom Air Force Base / Peru varies throughout the year.
The wetter season lasts 5.4 months, from March 27 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 40% on June 7.
The drier season lasts 6.6 months, from September 8 to March 27. The smallest chance of a wet day is 18% on February 5.
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 40% on June 7.
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. Grissom Air Force Base / Peru experiences significant seasonal variation in monthly rainfall.
Rain falls throughout the year at Grissom Air Force Base / Peru. 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 February 3, with an 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 of the year. Grissom Air Force Base / Peru experiences some seasonal variation in monthly liquid-equivalent snowfall.
The snowy period of the year lasts for 4.3 months, from November 23 to April 2, with a sliding 31-day liquid-equivalent snowfall of at least 0.1 inches. The most snow falls during the 31 days centered around January 31, with an average total liquid-equivalent accumulation of 0.5 inches.
The snowless period of the year lasts for 7.7 months, from April 2 to November 23. The least snow falls around July 15, with an average total liquid-equivalent accumulation of 0.0 inches.
Average Liquid-Equivalent Monthly Snowfall
The length of the day at Grissom Air Force Base / Peru varies significantly over the course of the year. In 2017, the shortest day is December 21, with 9 hours, 16 minutes of daylight; the longest day is June 21, with 15 hours, 5 minutes of daylight.
Hours of Daylight and Twilight
The earliest sunrise is at 6:13 AM on June 14, and the latest sunrise is 2 hours, 6 minutes later at 8:18 AM on November 4. The earliest sunset is at 5:17 PM on December 7, and the latest sunset is 4 hours, 2 minutes later at 9:19 PM on June 27.
Daylight saving time (DST) is observed at Grissom Air Force Base / Peru during 2017, starting in the spring on March 12, lasting 7.8 months, and ending in the fall on November 5.
Sunrise & Sunset with Twilight and Daylight Saving Time
Grissom Air Force Base / Peru experiences extreme seasonal variation in the perceived humidity.
The muggier period of the year lasts for 3.9 months, from May 24 to September 22, 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 55% of the time.
The least muggy day of the year is January 29, when muggy conditions are essentially unheard of.
Humidity Comfort Levels
The average hourly wind speed at Grissom Air Force Base / Peru experiences significant seasonal variation over the course of the year.
The windier part of the year lasts for 7.5 months, from October 8 to May 25, with average wind speeds of more than 9.8 miles per hour. The windiest day of the year is January 15, with an average hourly wind speed of 12.5 miles per hour.
The calmer time of year lasts for 4.5 months, from May 25 to October 8. The calmest day of the year is August 3, with an average hourly wind speed of 7.2 miles per hour.
Average Wind Speed
The predominant average hourly wind direction at Grissom Air Force Base / Peru varies throughout the year.
The wind is most often from the south for 2.9 months, from April 4 to July 2 and for 3.3 months, from August 10 to November 20, with a peak percentage of 37% on November 14. The wind is most often from the west for 1.3 months, from July 2 to August 10 and for 4.5 months, from November 20 to April 4, with a peak percentage of 34% on July 20.
Best Time of Year to Visit
To characterize how pleasant the weather is at Grissom Air Force Base / Peru 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 Grissom Air Force Base / Peru for general outdoor tourist activities is from mid 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 Grissom Air Force Base / Peru for hot-weather activities is from late June to late 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 at Grissom Air Force Base / Peru typically lasts for 6.1 months (188 days), from around April 15 to around October 20, rarely starting before March 27 or after May 3, and rarely ending before October 1 or after November 8.
Time Spent in Various Temperature Bands and the Growing Season
Based on growing degree days alone, the first spring blooms at Grissom Air Force Base / Peru should appear around April 6, only rarely appearing before March 23 or after April 23.
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 3.8 months, from May 1 to August 27, with an average daily incident shortwave energy per square meter above 5.9 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 3.2 months, from November 4 to February 11, with an average daily incident shortwave energy per square meter below 2.7 kWh. The darkest day of the year is December 18, with an average of 1.7 kWh.
Average Daily Incident Shortwave Solar Energy
For the purposes of this report, the geographical coordinates of Grissom Air Force Base / Peru are 40.648 deg latitude, -86.152 deg longitude, and 791 ft elevation.
The topography within 2 miles of Grissom Air Force Base / Peru is essentially flat, with a maximum elevation change of 49 feet and an average elevation above sea level of 797 feet. Within 10 miles is essentially flat (285 feet). Within 50 miles contains only modest variations in elevation (591 feet).
The area within 2 miles of Grissom Air Force Base / Peru is covered by cropland (82%) and artificial surfaces (18%), within 10 miles by cropland (94%), and within 50 miles by cropland (92%).
This report illustrates the typical weather at Grissom Air Force Base / Peru, 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
Grissom Air Force Base / Peru has a weather station that reported reliably enough during the analysis period that we have included it in our network. When available, historical temperature and dew point measurements are taken directly from this weather station. These records are obtained from NOAA's Integrated Surface Hourly data set, falling back on ICAO METAR records as required.
In the case of missing or erroneous measurements from this station, we fall back on records from nearby stations, adjusted according to typical seasonal and diurnal intra-station differences. For a given day of the year and hour of the day, the fallback station is selected to minimize the prediction error over the years for which there are measurements for both stations.
The stations on which we may fall back include but are not limited to Kokomo Municipal Airport, Logansport Cass County Airport, Fulton County Airport, Indianapolis Executive Airport, Warsaw Municipal Airport, Purdue University Airport, Eagle Creek Airpark, and Starke County Airport.
Time zones for aiports and weather stations are provided by AskGeo.com .