| June 2002 | Thunderstorm Wind | Altamont | 1 hurt | Numerous trees, tree limbs, and power lines were blown down in Altamont, Effingham, and Teutopolis. Some homes in Effingham sustained siding damage and a small shed was destroyed by a fallen tree. The roof of the junior high school in Teutopolis sustained minor damage. Also, a semi was blown over on southbound I-57 in Effingham. The driver sustained minor injuries. |
| November 2013 | Tornado (EF1) | Altamont | $400,000 | This tornado continued from Fayette County in National Weather Service St. Louis' County Warning Area (CWA). The tornado crossed into Effingham County 3.2 miles WNW of Altamont at 12:28 PM CST before tracking northeastward and dissipating 2.9 miles NNW of Altamont at 12:32 PM CST. About a dozen outbuildings were damaged and minor damage occurred to the roofs of 3 homes. Several power poles were blown down as well. The tornado dissipated near North 200th Street and East 1300th Avenue in rural Effingham County. |
| July 2018 | Thunderstorm Wind | Altamont | $90,000 | Numerous trees and power lines were blown down in Altamont. A few houses were damaged by falling trees. |
| July 2016 | Thunderstorm Wind | Altamont | $60,000 | Numerous large tree branches were blown down in Altamont. Some of the branches fell onto homes, causing minor damage. |
| February 2008 | Thunderstorm Wind | Altamont | $45,000 | A mobile home was destroyed 7 miles south of Altamont. In addition, numerous trees and power lines were blown down. |
| February 2011 | Thunderstorm Wind | Altamont | $30,000 | Power poles were bent over and a pole barn suffered minor damage. |
| February 2011 | Thunderstorm Wind | Altamont | $30,000 | A lean-to shed was destroyed and minor roof damage occurred to a house. |
| February 2011 | Thunderstorm Wind | Altamont | $25,000 | Power poles were bent over and numerous tree limbs were blown down. |
| January 2013 | Thunderstorm Wind | Altamont | $20,000 | A large overhead door was blown out at the ADM plant. A tree was blown down onto a house, doing damage to its roof. In addition, numerous tree branches were knocked down around town. |
| May 2011 | Thunderstorm Wind | Altamont | $20,000 | Several powerlines were blown down. |
| June 2008 | Thunderstorm Wind | Altamont | $20,000 | Several trees and tree limbs were blown down. |
| April 2016 | Thunderstorm Wind | Altamont | $18,000 | A power pole was blown down and a semi truck was knocked over on I-70. |
| April 2015 | Thunderstorm Wind | Altamont | $12,000 | Several large tree branches were blown down across County Road 1200 N about 2 miles northwest of Altamont. |
| September 2012 | Thunderstorm Wind | Altamont | $12,000 | Railroad crossing gates were torn off at 10th and Division Streets in Altamont. In addition, several trees and tree branches were blown down. |
| October 2007 | Thunderstorm Wind | Altamont | $12,000 | Numerous trees were blown down.| |
| June 2018 | Thunderstorm Wind | Altamont | $6,000 | Several tree limbs were blown down along Highway 128 west of Altamont. |
| June 2010 | Thunderstorm Wind | Altamont | $4,000 | A large tree was blown down onto power lines along US Route 40 near Altamont. |
| August 1995 | Thunderstorm Wind | Altamont | $200 | The Illinois State Police reported large trees down. |
| March 2026 | Thunderstorm Wind | Altamont | - | Power lines were blown down. |
| May 2025 | Thunderstorm Wind | Altamont | - | Tree branches were blown down across Route 40 southwest of Altamont. |
| April 2025 | Thunderstorm Wind | Altamont | - | The roofs of two apartment buildings were torn off. |
| April 2025 | Thunderstorm Wind | Altamont | - | An outbuilding was blown onto a road. |
| April 2025 | Tornado (EF1) | Altamont | - | A tornado touched down in a field just northwest of the intersection of North 500th Street and East 700th Avenue at 6:08 PM CDT. The tornado tracked northeastward, stripping part of the roof off a home and damaging several trees along its path before dissipating near Second Creek north of the intersection of North 675th Street and County Road 825 at 6:11 PM CDT. |
| June 2025 | Thunderstorm Wind | Altamont | - | Large branches, trees, and power lines were blown down in the town of Altamont. |
| June 2025 | Thunderstorm Wind | Altamont | - | A 12 inch diameter tree branch was snapped in Altamont. A photo of the damage was shared via social media. |
| July 2025 | Flash Flood | Altamont | - | Water was flowing across Main Street between Division Street and Oak Street. |
| February 2023 | Thunderstorm Wind | Altamont | - | Powerlines were blown down. |
| April 2023 | Thunderstorm Wind | Altamont | - | Trees were blown down onto power lines and the roadways. A few power outages occurred. |
| June 2022 | Thunderstorm Wind | Altamont | - | Numerous large trees and tree branches were blown down around Altamont. Some vehicle damage was reported due to falling branches. A garage door buckled in and the siding of a house was damaged. The most significant wind damage occurred along West Jefferson Avenue between 7th Street and 10th Street. |
| May 2021 | Tornado (EFU) | Altamont | - | A tornado touched down in a field 1.9 miles south of Altamont at 3:10 PM CDT. The tornado quickly dissipated by 3:11 PM CDT. No damage occurred. |
| May 2018 | Thunderstorm Wind | Altamont | - | An 8-inch diameter limb was ripped off a tree. |
| May 2018 | Thunderstorm Wind | Altamont | - | A two-inch diameter tree branch approximately 10 to 12 inches long was blown down. |
| May 2017 | Flash Flood | Altamont | - | The third heavy rain event to occur in less than two weeks resulted in rapid flash flooding in southern Effingham County. Rainfall amounts ranged from 2.00 to 2.50 inches during the late evening of May 10th in areas where ditches were already full of water and soils were saturated. Numerous rural roads were closed near Mason and Edgewood, and water covered parts of U.S. Highway 45 south of Watson to the Clay County line. |
| May 2017 | Flood | Altamont | - | The third heavy rain event to occur in less than two weeks resulted in rapid flash flooding in southern Effingham County. Rainfall amounts ranged from 2.00 to 2.50 inches during the late evening of May 10th in areas where ditches were already full of water and soils were saturated. Numerous rural roads were closed near Mason and Edgewood, and water covered parts of U.S. Highway 45 south of Watson to the Clay County line. An additional 0.50 to 0.75 inch of rain during the early morning hours of May 11th kept flood waters from receding until daybreak. |
| April 2016 | Tornado (EF0) | Altamont | - | A tornado briefly touched down in an open field about 3.2 miles south-southwest of Altamont at 6:58 PM CDT. No damage occurred. |
| July 2015 | Flash Flood | Altamont | - | Slow moving thunderstorms produced 2.00 to 3.00 inches of rain in 90 minutes during the evening of July 1st in west central Effingham County. The ground was already saturated from periods of heavy rainfall in late June, so flash flooding developed quickly. Most rural roads from Altamont to Gilmore were impassable through the late evening. |
| September 2014 | Flash Flood | Altamont | - | Heavy downpours which produced 2 to 3 inches of rain per hour between 2200-0000 local time resulted in flash flooding across the southern half of Effingham County. Numerous rural roads were impassable, streets in the towns of Mason and Edgewood were flooded, and parts of U.S. Highway 45 near the Clay County line were closed. Several motorists had to be rescued after they drove into flooded ditches. The flooding subsided within three hours. |
| June 2013 | Flash Flood | Altamont | - | Slow moving thunderstorms, which produced 3.00 to 4.00 inches of rain on already saturated ground from the late evening of May 31st through the night across much of Effingham County, resulted in flash flooding which continued into the early afternoon of June 1st. The flash flooding made many rural roads impassable, and flooded numerous streets in the city of Effingham. |
| May 2013 | Flash Flood | Altamont | - | Slow moving thunderstorms produced 3.00 to 4.00 inches of rain on already saturated ground from late evening through the night across much of Effingham County. This rapidly produced flash flooding which made many rural roads impassable, and flooded numerous streets in the city of Effingham. The flash flooding continued through the night, and into June 1st. |
| June 2011 | Flash Flood | Altamont | - | Thunderstorms during the late evening hours produced 3.00 to 4.00 of rain on extremely saturated ground. This resulted in rapid flash flooding of creeks and roads in southern Effingham County. Parts of I-57 and U.S. Highway 45 had several areas of standing water. Illinois Route 37 and nearly all rural roads were water covered and impassable. |
| February 2009 | Flood | Altamont | - | Numerous low-lying county roads across Effingham County had water flowing across them. |
| May 2009 | Flash Flood | Altamont | - | Heavy rain of 2.00 to 3.00 inches within two hours, on top of already saturated ground, produced significant flash flooding of most roads across southern Effingham County. Many roads were closed to traffic due to high water. |
| April 2006 | Thunderstorm Wind | Altamont | - | Two small homes destroyed by trees falling on them. |
| May 2006 | Thunderstorm Wind | Altamont | - | Numerous trees and power lines were blown down. |
| May 2005 | Thunderstorm Wind | Altamont | - | Trees and power lines blown down. |
| June 2005 | Thunderstorm Wind | Altamont | - | Empty silo blown down. |
| July 2004 | Thunderstorm Wind | Altamont | - | A tree was blown down onto a power line. |
| April 2001 | Hail | Altamont | - | Hail ranged from dime to quarter size. |
| July 2001 | Flash Flood | Altamont | - | At 525 am CST, a street was reported flooded in the town of Altamont. By 650 am CST, numerous streets were reported flooded in the town. |
| August 2000 | Thunderstorm Wind | Altamont | - | Several power lines were blown down in Altamont and Effingham, mainly due to fallen tree limbs. |
| June 2000 | Thunderstorm Wind | Altamont | - | Several trees, tree limbs and power lines were blown down. A care center in Altamont sustained minor damage with a couple of windows broken, an air conditioning unit blown off concrete blocks, a TV antenna wrapped around the mast and numerous shingles blown off. A suspended ceiling in a large assembly room fell and several garage doors were damaged. |
| July 2000 | Thunderstorm Wind | Altamont | - | Several power lines were blown down in Altamont. |
| June 1999 | Tornado (F0) | Altamont | - | A tornado briefly touched down near the intersection of IL Route 128 and US 40. It uprooted a few trees and knocked down some power lines. No injuries were reported. |
| June 1998 | Thunderstorm Wind | Altamont | - | Thunderstorm winds blew down several trees, numerous tree limbs, and power lines in Altamont. No injuries were reported. Some minor structural damage was reported though no damage estimate was available. |
| July 1997 | Thunderstorm Wind | Altamont | - | Thunderstorm winds blew down several large trees in Altamont. |
| March 2025 | Hail | Altamont | - | no account filed |
| October 2025 | Hail | Altamont | - | no account filed |
| September 2025 | Hail | Altamont | - | no account filed |
| August 2023 | Hail | Altamont | - | no account filed |
| August 2023 | Hail | Altamont | - | no account filed |