Ontario County

Every recorded tornado

1. Injuries and deaths are for the tornado’s whole path, which may extend beyond the county. Deaths recorded within Ontario County: 0.
2. Weak tornadoes were under-recorded before Doppler radar coverage became national in the early 1990s, so earlier decades read low. Ratings use the Fujita scale before February 2007 and the Enhanced Fujita scale after.

Storm Prediction Center severe weather database, 1950 to 2025.

Every storm within 100 miles

1. Tropical storms and hurricanes (34 kt or more, still tropical) at closest approach. Post-tropical remnants with gale-force winds are listed but not counted. Direct: track within 50 miles; near: within 100 miles. Distance is measured to the county boundary for counties and to the city centre for cities, using positions interpolated hourly between HURDAT2 fixes.

National Hurricane Center HURDAT2, 1851 to 2025.

Smoke overhead

1. A smoke day is a date on which a smoke plume traced by NOAA Hazard Mapping System analysts from satellite imagery covered this place's point (the county's population centre or the city centre). Counts here are of medium or heavy smoke. Since 2018 analysts have often drawn light smoke as one area over most of the continent, so light-smoke counts are not comparable from year to year. The plumes show smoke anywhere in the air above, not air quality at the ground, and smoke hidden by cloud is missed.

NOAA Hazard Mapping System smoke analysis, 2011 to 2026, retrieved October 30, 2026.

Claims by ZIP code

This product uses the Federal Emergency Management Agency's OpenFEMA API, but is not endorsed by FEMA. The Federal Government or FEMA cannot vouch for the data or analyses derived from these data after the data have been retrieved from the Agency's website(s).

OpenFEMA NFIP Redacted Claims v3, refreshed August 4, 2026. NOAA Storm Events through 2026.

River crests

River gauges

1. Crests are the highest and the recent crests the National Weather Service lists for each river gauge in the county that has a flood stage, not every flood. Flood categories use each gauge's current flood stages; crests from before levees, dams or channel changes may not be comparable. Crests measured on an old datum are left out of the rankings.

NOAA National Water Prediction Service gauge records, retrieved October 30, 2026.

1. The Palmer Drought Severity Index is computed by NOAA each month from the county's average temperature and precipitation, relative to the county's own climate. Zero is normal; -3 or lower is severe drought and -4 or lower extreme drought. It describes the long-term balance of moisture, not water supply or crop losses.

NOAA NCEI nClimDiv county Palmer Drought Severity Index, 1895 to September 2026, issued October 6, 2026.

Every earthquake of magnitude 4 or more within 50 miles

1. Earthquakes of magnitude 2.5 or more in the USGS Comprehensive Catalog since 1900. Within 50 miles means the epicentre lies within 50 miles of the county boundary (or inside the county).
2. Small earthquakes were under-recorded before the modern seismic networks of the 1970s and are still missed in remote areas, so early decades read low. Magnitudes are as the catalogue reports them and mix scales (moment, local and body-wave).

USGS ANSS Comprehensive Earthquake Catalog, 1900 to present, retrieved October 30, 2026.

Mapped landslides

Mapped by NASA (2).

1. Landslides mapped in the USGS compilation of landslide inventories across the United States (version 3.0, 2025), rated probable or better. The compilation joins inventories made by federal and state agencies for different purposes and areas, so the number mapped in a county reflects how closely it has been surveyed as much as how often its slopes fail. An area with few records may simply not have been mapped. Deaths are as recorded in the inventories; a slide listed in two inventories is counted once.

USGS Landslide Inventories across the United States, version 3.0, retrieved October 27, 2026.

More event types since 1996

Costliest events since 1996

1. May 20, 2004Flash Flood$6.0 million
   National Weather Service narrative

   Slow moving thunderstorms dumped three to four inches of rain in less than an hour on parts of Ontario county. The Town of Naples was hardest hit. Many roads were washed out. Others were covered with up to three feet of debris and gravel and were impassable. Roads affected included County Routes 36 and 37, Gulick Road and Routes 21 and 245. Schools were closed on the 21st because of hazardous driving conditions. In South Bristol, rocks and mud slid down a hill and partially buried a home. Tons of debris filled the house. Some roads could take weeks to rebuild and re-open. County Emergency management estimated $2 million in damage to private property and nearly $4 million in…

2. Apr 5, 2003Ice Storm, Ontario$3.0 million
   National Weather Service narrative

   Low pressure over Illinois brought a mix of wintry weather to parts of the Genesee Valley, the Finger Lakes and the North Country. Across the North Country the precipitation mainly fell as snow mixed with sleet at times. Nine to twelve inches accumulated over the higher elevations. Across the Genesee Valley and the Finger Lakes, the precipitation fell mainly as freezing rain. Up to an inch of ice accumulation was measured. Hardest hit areas were eastern Monroe, Wayne and northern Cayuga counties. A Federal Disaster Declaration included Livingston, Monroe, northern Cayuga, Ontario, Orleans, Oswego, and Wayne counties. The heavy ice accumulation downed trees, limbs and power and…

3. Jan 19, 1996Flood, Ontario$2.2 million
   National Weather Service narrative

   Rapid snowmelt of 1-2 feet of snow combined with heavy rainfall of about an inch to produce significant flooding.

4. Aug 5, 2003Flash Flood$2.0 million
   National Weather Service narrative

   Thunderstorms during the afternoon hours produced several inches of rain over parts of the southern tier to the Finger Lakes region. The heavy rains fell on already saturated ground from storms over the past several weeks. Rainfalls of over an inch and a half in a half hour were reported. In Allegany county, the heavy rains again caused flash flooding and road closures over an area already hard hit and damaged by flooding in July. State Routes 417 and 19 were closed as culverts overflowed. In Ontario county, the towns of Honeoye, East Bloomfield, Bristol, Naples and Richmond were affected by flooding. Several roads were washed out and debris and tree limbs were littered throughout…

5. Apr 26, 2011Flash Flood$1.1 million
   National Weather Service narrative

   A line of showers and thunderstorms crossed the area during the evening hours. The thunderstorms were accompanied by strong winds, large hail and intense rains. The winds downed trees and wires on Whig hill and one inch hall fell in Scio. Following an extremely wet spring, any rain the fell on the saturated ground became runoff. The two to three inches of rainfall resulted flash flooding in Allegany and Ontario counties. In Wellsville, two to three feet of water washed across the streets with over a dozen streets closed or washed out. In Allegany county, damage was also reported in Alfred, Andover, Angelica, Granger, West Almond and Friendship. In Ontario county, basements were…

6. Sep 7, 1998Thunderstorm Wind$1.0 million
   National Weather Service narrative

   Severe thunderstorms moved onshore over northeast Niagara county shortly before midnight near Olcott and Golden Hill State Park in Barker. The line of storms quickly moved across Orleans, Monroe, Wayne, Ontario, and northern Cayuga counties. Across the area the damage path was nearly one hundred miles long and five to ten miles wide. Winds were estimated between 80 and 100 mph throughout the two hour event. Along the entire path, damage and debris all laid in an easterly direction consistent with the damage from straight-line winds. Most of the damage consisted of downed trees and limbs. The falling trees and limbs in turn downed power and telephone lines and resulted in damage to…

7. Aug 29, 2009Tornado$500,000
   National Weather Service narrative

   NWS storm survey confirmed tornado touchdown.

8. Feb 1, 2002High Wind, Ontario$500,000
   National Weather Service narrative

   An intensifying storm moved across the Great Lakes and lifted northeast to the St. Lawrence Valley. Very strong winds behind the low blasted the region with wind gusts exceeding 55 mph. Trees and power lines were downed by the strong winds. Hundreds of thousands were without power...some for several days. Fallen trees and limbs littered the area and closed roads. Numerous reports of damage to homes and automobiles were received from throughout the area. Driving bans and States of Emergency were declared in several counties. Numerous school districts were forced to close on the first and several remained closed through the beginning of the following week. In Monroe county, two…

9. Mar 16, 2004Heavy Snow, Ontario$300,000
   National Weather Service narrative

   A low pressure system strengthened over the mid-Mississippi valley, moved to the Virginias, then tracked northeast along the Atlantic coast. The late season storm produced ten to twenty inches of heavy, wet snow across much of the region. The snow began across the western southern tier around daybreak on the 16th and during the morning hours across the Niagara frontier and western Finger Lakes region. The snow continued, heavy at times, throughout the day and then began to taper off at midnight. Many schools and businesses heeded warnings, closed on the 16th and remained closed on the 17th. The storm was blamed for numerous automobile accidents, including several fatalities.…

10. May 29, 2002Flash Flood$250,000
    National Weather Service narrative

    Thunderstorms developed in warm, moist, unstable air during the afternoon and evening hours downing trees and power lines. Up to 5000 homes were without power at the peak of the storm. Hail up to 1 inch in diameter was reported in Perry, Wyoming county. The training thunderstorms dropped four to six inches of rain in two to three hours in a localized area from Phelps to Newark. A State of Emergency was declared that was declared in Newark remained in effect for a week with most schools and businesses closed during that time. Nearly 300 basements were flooded and several roads covered with up to a foot of water remained closed for several days.

1. Storm Events records before 1996 cover only tornadoes, thunderstorm wind and hail. Damage figures are as reported by the National Weather Service at the time, not adjusted for inflation.

NOAA NCEI Storm Events Database, 1950 to 2026, issued October 26, 2026.

All-time high

101°FAug 10, 2001

All-time low

−17°F2 times, most recently Feb 18, 1979

Warmest night

82°F2 times, most recently Jul 6, 1999

Coldest day

0°F2 times, most recently Feb 14, 2016

Wettest day

3.71 inJul 29, 2014

Snowiest day

18.0 inJan 18, 2022

Hottest year

2012mean 52.1°F

Coldest year

1963mean 46.2°F

Wettest year

201744.95 in

Driest year

198821.60 in

Station Canandaigua 3 S (USC00301152), 720 ft elevation, 4.0 miles from the population centre. Daily records from 1944 to October 27, 2026; 98.6% of days in the last 30 years are complete. Records at a single station can differ from a city’s official threaded record, which may combine several stations.

NOAA NCEI Global Historical Climatology Network Daily.

This product uses the Federal Emergency Management Agency's OpenFEMA API, but is not endorsed by FEMA. The Federal Government or FEMA cannot vouch for the data or analyses derived from these data after the data have been retrieved from the Agency's website(s).

OpenFEMA Disaster Declarations Summaries, retrieved October 30, 2026. Statewide declarations are not listed.

Neighbouring counties

• Tornadoes NOAA Storm Prediction Center severe weather database, through 2025.
• Tropical cyclones NOAA National Hurricane Center HURDAT2 (Atlantic; Northeast and Central Pacific), through 2025.
• Wildfire USGS/USFS Monitoring Trends in Burn Severity, through 2026.
• Storm events NOAA NCEI Storm Events Database, through 2026.
• Flood insurance OpenFEMA NFIP Redacted Claims v3, refreshed August 4, 2026.
• Declarations OpenFEMA Disaster Declarations Summaries v2, retrieved October 30, 2026.
• Weather records NOAA NCEI Global Historical Climatology Network Daily, station USC00301152.
• River crests NOAA National Weather Service, National Water Prediction Service river gauges, retrieved October 30, 2026.
• Drought NOAA NCEI nClimDiv county Palmer Drought Severity Index, through September 2026.
• Smoke NOAA NESDIS Hazard Mapping System smoke analysis, retrieved October 30, 2026.
• Landslides USGS Landslide Inventories across the United States, version 3.0 (2025).
• Earthquakes USGS ANSS Comprehensive Earthquake Catalog (ComCat), retrieved October 30, 2026.

Joins, thresholds and known limits are set out in the methodology. Found an error? Report it. Page built October 30, 2026.