Indiana experiences a humid continental type of climate (Köppen climate classification Dfa, Dfb) in the northern and central regions of the state and a humid subtropical climate (Köppen Cfa) in the south. Hot summers and cold winters are typical, with a gradual increase in warmth in the southern regions. Indiana lies in the Midwestern and Great Lakes region of North America. Ohio in the west, Kentucky in the south and southeast, Illinois in the west, Lake Michigan in the northwest, and Michigan in the north, border the state. Location in the continent, scarcity of high mountain ranges, and the Gulf of Mexico are major players that influence the climate.
Indiana, the Hoosier State, has an average elevation of 210 meters above sea level, with the highest point at Hoosier Hill at 383 meters. The topography mainly consists of flat plains in the northern two-thirds, and hills, caves, ridges, and waterfalls in the south. Indiana comprises of two natural regions: the Central Lowlands and the Interior Low Plateaus of the United States. Along the Lake Michigan shoreline, there are sand ridges and dunes in the northwest. The central region is mainly flat, and the soil is favorable for agriculture. The Hoosier National Forest and much of southcentral Indiana has rugged, hilly terrain.
Indiana has strongly marked seasons with an invigorating climate. Summers are hot, humid, and wet. High temperatures pass the 100°F (37.8°C) mark at the peak of the summer in July, and the humidity becomes oppressive. Winters are cold and bitter, with night temperatures below 15°F (-9.4°C) in the north during the trough of January. Cold air masses from the polar areas move southward, and hot air from the tropics moves northward to produce frequent weather changes in the winter. Spring is an active season for tornadoes and thunderstorms as the weather changes from cold to hot. Autumn has mostly sunny skies and pleasant temperatures with low humidity. Lake Michigan has a prominent effect on the climate of northern Indiana in all seasons.
Indiana registers an average of 42" (1066.8mm) of rainfall annually, increasing from north to south, and a significant uptick during the summer compared to the rest of the year. Snowfall ranges from 14" (355.6mm) in the southwest to 76" (1930.4mm) in the northcentral snow belt near Lake Michigan. The snow season typically begins by mid-November and lasts till mid-April, depending upon latitude and altitude of the region. The Great Lakes region is the cloudiest in the state, while autumn is the sunniest season and winter the cloudiest. The average annual sunshine lasts for 2400 hours, with 190 to 200 days when the cloud cover is less than 40% of the sky during daylight hours.
The record high temperature for Indiana is 116°F (46.7°C), set in Collegeville on July 14, 1936, while the lowest recorded temperature is -36°F (-37.8°C), set in New Whiteland on January 19, 1994.
The best time to visit Indiana
The best time to visit Indiana is in the autumn season from September and October when the temperatures are pleasant, and the skies are clear. The sunny days register temperatures in the 65°F (18.3°C) to 85°F (29.4°C) zone, while the nights are in the range of 40°F (4.4°C) to 60°F (15.6°C). The rainfall ceases significantly from the high of summer and is light to moderate. Storm activity eases considerably by the end of September, and the season is the most colorful time of the year. Summers are hot and humid in Indiana and the time of peak tourist activity. Fall trips are more economical than in the summer.
The worst time to visit Indiana
The worst time to visit Indiana is from December to February when the state lies in the grip of severe cold weather. Low temperatures often drop to extremes that can reach 0°F (-17.8°C) as strong wind speeds keep the conditions chilly. Polar air masses frequently invade the northern regions and even affect the south to a degree. Snowstorms are frequent in the winter, with a vast accumulation of snow within a short period. Northern Indiana is the snowiest region due to the presence of lake effect snow in the Lake Michigan area. However, prolonged spells are rare in the state.
Indiana is vulnerable to thunderstorms, tornadoes, floods, and droughts in spring and summer. Floods occur every year with the highest frequency during the spring due to heavy rainfall and melting of snow. Indiana is not part of the Tornado Alley of the United States, yet reports an average of 23 tornadoes in the year, with the most during the spring. Wind speeds over 100 miles per hour are responsible for damage to life and property during severe storms. Thunderstorms occur with alarming frequency, while hailstorms occasionally occur in the summer. Snowstorms are frequent in the winter, especially in the northern region.
Weather in January
January is usually the coldest month of the year in Indiana when the temperatures drop in the frigid zone. The average temperatures in Indianapolis, the capital in the central region, are between 21°F (-6.1°C) to 36°F (2.2°C), while they range in the cold 15°F (-9.4°C) to 44°F (6.7°C) range statewide. The rainfall amounts to less than 3" (76.2mm) as ice and snow replace it as a form of precipitation. January is the snowiest month of the year with 10" (254mm) of snow in many parts in the north, while the south registers 4" (101.6mm) to 5" (127mm). The skies are partly cloudy and tend to be gloomy in the absence of intense sunshine. Warm winter coats serve well in the cold season, especially when the wind speeds are high. Ice fishing, ice skating, and skiing are popular with locals and tourists alike. Pockets of mild weather occur in the south for brief periods. However, January is a discount season in Indiana, with a shortage of visitors due to the severe cold.
Weather in February
February is the driest month of the year in Indiana as the average rainfall drops below 2.5" (63.5mm) in the state. Lake effect snow is prominent in northwest Indiana in the proximity of Lake Michigan. February snowfall is in the range of 8" (203.2mm) to 12" (304.8mm), with one of the highest numbers in South Bend at 15" (381mm). In central and southern parts, the snow and cold increases towards the east due to high elevations. Snowstorms are frequent as polar air masses reach the heart of Indiana. The average temperatures vary from a cold 17°F (-8.3°C) during the night to a warm 50°F (10°C) in the day. Evansville in the south is mild between 30°F (-1.1°C) to 50°F (10°C) compared to Fort Wayne in the north, between 20°F (-6.7°C) to 36°F (2.2°C). Expect the conditions to be cold, and drive carefully on the hazardous roads rendered slippery due to ice and snow. February does not allow venturing outside without the warmth of winter coats in Indiana.
Weather in March
March transitions to the beautiful spring season in Indiana, and sees a steady rise in temperatures and sunshine. The average temperatures in the north are between 25°F (-3.9°C) to 48°F (8.9°C), while the central region register between 29°F (-1.7°C) to 54°F (12.2°C) and the southern in the 30°F (-1.1°C) to 61°F (16.1°C) range. A slight uptick sees rainfall in the 3" (76.2mm) to 4" (101.6mm) range in the majority of the regions. Snowfall is light in the south, but registers at least 4" (101.6mm) to 5" (127mm) in many places in the north. Spring is unpredictable, with a cold wave always on the cards. Early tourists need to watch for tornadoes and thunderstorms that regularly invade Indiana. Many houses have built-in storm shelters, and consequently, the damage due to storms is less. Nights are cold in the early part of the spring season, so keep warm coats at hand. Mornings are refreshing with a tinge of cold amid warm sunshine. Late March brings greenery and mild temperatures in Indiana.
Weather in April
April is a warm and wet month in Indiana, with 3" (76.2mm) to 5" (127mm) of rain in the middle of the spring season. The prairie wears a blanket of greenery as the snow cover disappears from the landscape. Apart from light snow in the northern regions, the majority of the state is free from snow. The growing season begins in central Indiana with the unfreezing of the soil. The average high temperatures are in the pleasant 58°F (14.4°C) to 72°F (22.2°C) range, while the average low temperatures are above freezing in the 36°F (2.2°C) to 48°F (8.9°C) range. Lafayette in the center registers between 41°F (5°C) to 62°F (16.7°C), while Bloomington in the south is between 42°F (5.6°C) to 64°F (17.8°C). The rain and melting snow bring a fresh supply of water to the rivers, lakes, and streams. The 7 hours of daily sunshine create a pleasant atmosphere for boating, fishing, and hiking. Easter time by the fourth week of April is a beautiful time to visit Indiana with warm temperatures.
Weather in May
May is the wettest month of the year in Indiana and the period that sees the highest number of storms. The precipitation is to the tune of 4" (101.6mm) to 6" (152.4mm), and the southern parts tend to be wetter than the northern ones. There is no shortage of warmth in May, with the daily sunshine lasting at least for 8 hours. The average day temperatures are in the beautiful 69°F (20.6°C) to 81°F (27.2°C) range, while the nights are comfortable between 47°F (8.3°C) to 58°F (14.4°C). The last remnants of snow disappear by early May, even in the coldest zones of the state. Late spring has the highest frequency of tornadoes, but they are rarely life-threatening due to the slew of counteracting measures. Between the thunderstorms and wet periods, the ample number of sunny days sees the cacophony of singing birds, and animals. Wear rain jackets and keep an eye on the weather when outdoors. May is usually a time to avoid Indiana due to stormy and wet conditions.
Weather in June
June begins the summer season in Indiana as the sun takes charge of the weather. The longest days of the year bring bright sunshine in their tow as the heat and humidity become oppressive. The average high temperatures are in the warm 78°F (25.6°C) to 85°F (29.4°C) range, while average low temperatures hover between 57°F (13.9°C) to 67°F (19.4°C). Thunderstorms bring the majority of the 4" (101.6mm) of rainfall, and tornadoes remain active. Hail is a feature of the rainfall and damages crops in many parts. Humidity induces much sweating, and sweatshirts are best to wear during the day. Swimming, hiking, and biking are popular activities during the day. Many people like the experience of camping in the open, with wildflowers, and abundant freshwater sources. Dawn and dusk are the times to expect the movement of wildlife. The vast open prairie has some of the clearest skies for stargazing activities. June brings tourists to Indiana on the back of sunny weather.
Weather in July
July is by far the hottest month of the year in Indiana, but extreme temperatures are uncommon. The average high temperatures in the state are between 82°F (27.8°C) to 92°F (33.3°C), and the average low temperatures are in the warm range of 61°F (16.1°C) to 70°F (21.1°C). Day temperatures often cross 95°F (35°C) in the south, and places like Evansville and Charlestown register between 64°F (17.8°C) to 92°F (33.3°C), with a sharp drop during the night. The 8 to 9 hours of daily sunshine bring oppressive heat in the wake of high humidity. Thunderstorms with lightning and heavy rain are frequent at the peak of summer, and it advisable to keep an eye on the weather for storm activity. Keep in mind that mornings and evenings are the best times while exploring state parks such as The Indiana Dunes State Park and Turkey Run State Park. The hot and muggy conditions are favorable for swimming, boating, and fishing in the creeks, lakes, and rivers. July is the prime time for summer vacations in Indiana.
Weather in August
August is hot and humid month in Indiana, with the temperatures stuck at the high end of the range. Day temperatures are between 80°F (26.7°C) to 91°F (32.8°C), while nights are relatively mild in the 59°F (15°C) to 69°F (20.6°C). The relative humidity is lower in the south than in the north, but the south often faces the combination of high temperature and high humidity that make the heat oppressive. Central Indiana is hot, with the regions in the east wetter than the rest. The 3" (76.2mm) to 4" (101.6mm) of rainfall is particularly useful for agriculture in the central region. At least 21 sunny days are evident in August, but storms, particularly tornadoes, are active even in late summer. The hot conditions make a good case for wearing sweatshirts and t-shirts when out on the open prairie or the high hills. Lakeside spots are popular for summer vacations, although the boats are not as big as those in the states with extensive coastlines. August sees a rise in tourist numbers in Indiana.
Weather in September
September brings pleasant weather to Indiana as the mild autumn season arrives in the state. The summer rains recede to register 2" (50.8mm) to 3" (76.2mm) by early fall, with a significant reduction in storms. The sun adorns the skies for at least 21 days, with daily sunshine of 7 to 8 hours. Humidity is on the wane with the end of the summer, and the cloud cover is at the thinnest. The average high temperatures are in the comfortable 73°F (22.8°C) to 82°F (27.8°C) range, while the nights are temperate in the 50°F (10°C) to 60°F (15.6°C) zone. Rochester in the north is between 53°F (11.7°C) to 75°F (23.9°C), while Brookville in the south is slightly warmer between 54°F (12.2°C) to 80°F (26.7°C). Northern Indiana attains peak fall colors earlier than the central and southern parts. The landscape attains beautiful hues by the end of September in most parts. Fall is the time to pick apples and pumpkins and make campfires. September is one of the best times to visit Indiana.
Weather in October
October is temperate in Indiana and the period of peak fall foliage. The woods are colorful, and the lake shores offer beautiful views of the foliage. Local orchards are full of ripe apples, and abundant pumpkin patches dot the lands. The harvest season results in a bountiful of agricultural produce, especially in the central parts where the soil quality is superior. The average high temperatures are in the range of 61°F (16.1°C) to 70°F (21.1°C), while average low temperatures register between 39°F (3.9°C) to 50°F (10°C) across the state. Precipitation is low, but an unusually cold year may bring the first snowflakes in the north. Although the daylight and sunshine are ample, the nights tend to be cold. Peak fall foliage colors display throughout Indiana by the fourth week of October. Get lost in a corn maze along with friends and family, and enjoy the thrill of finding the way out at sunset. October is the last month of mild weather in Indiana.
Weather in November
November sees the fall season on its last legs in Indiana as the temperatures drop significantly. The average temperatures are between 30°F (-1.1°C) to 60°F (15.6°C), with the nights below freezing in many parts of northern Indiana. The first snowflakes of the season arrive in November, with a slight uptick in precipitation. The areas in the vicinity of Lake Michigan receive more snow than the rest of the state. November is the last mild weather month that offers a chance to pitch a tent and roast marshmallows by the campfire under the clear autumn skies at night. Photography is best during the fall, with sunny days and clear skies. Hop in a car or take a bike ride through the scenic byways and roads of the beautiful countryside to explore the colorful fall foliage. Enjoy an apple pie, a cider, or a craft beer while exploring the changing leaves during the pleasant weather. Expect the cold to increase with each passing day in November in Indiana.
Weather in December
December is severely cold in Indiana with the average low temperatures in the cold 34°F (1.1°C) to 48°F (8.9°C) range and the average low temperatures in the freezing 20°F (-6.7°C) to 30°F (-1.1°C) range. Temperature varies between different parts of the state and with altitude. The cold air persists for long periods in the valleys than the flatlands. Hobart in northern Indiana averages between 21°F (-6.1°C) to 35°F (1.7°C), while Evansville is milder 30°F (-1.1°C) to 48°F (8.9°C). Snowfall compensates for the reduction in rainfall to no small extent. Winds regularly blow at high speeds to increase the effect of cold. The extreme north records the highest snowfall in the range of 8" (203.2mm) to 10" (254mm), while the south receives light amounts. Expect the cold to increase with each passing day, and a winter storm is always lurking in the corner. Wear winter coats, caps, and gloves during outdoor visits. The conditions are unfavorable to visit Indiana in December except for a window of a few mild days.