NHC HURDAT2 · SPC Tornado Database
Hurricanes and Tornadoes That Hit Thornton, CO
Every tropical system within 75 miles since 1851 and every tornado within 25 miles since 1950.
Data: NOAA NHC HURDAT2 and NOAA SPC tornado and hail reports, through 2025 · Updated
No tropical storm or hurricane has passed within 75 miles of Thornton, Colorado since records began in 1851. Since 1950, 236 tornadoes have touched down within 25 miles, 4 of them rated EF3 or stronger.
- Hurricanes
- 0
- Tropical storms
- 0
- Tornadoes
- 236
- EF3 or stronger
- 4
within 75 mi, since 1851
below hurricane strength
within 25 mi, since 1950
no recorded deaths
What the records show for Thornton
The highest rating among the 236 tornadoes within 25 miles is F3 or EF3, reached 4 times; the most recent, on June 4, 2015, came within 25 miles. Of the 236, 5 had paths within 5 miles of the city centre, and 56 have come since 2000. June has had the most tornadoes, 105. The most recent tornado was on July 14, 2025. Thornton has more tornadoes within 25 miles than 91% of the 157 Colorado cities on this site. Hail has been reported within 10 miles 416 times since 1955, with stones up to 3 inches (tea cup size). Thornton has more hail reports within 10 miles than 89% of the 157 Colorado cities.
Compare Thornton's storm record with another city →
Tornadoes within 25 miles of Thornton
By decade
- 2020s13
- 2010s22(1 EF3+)
- 2000s21
- 1990s59
- 1980s74(2 EF3+)
- 1970s22(1 EF3+)
- 1960s17
- 1950s8
| Date | Rating | Distance | Path | Killed / injured |
|---|---|---|---|---|
| Jun 4, 2015 | EF3 | 25 mi | 6.71 mi | 0 / 0 |
| Jun 15, 1988 | F3 | 12 mi | 2.5 mi | 0 / 7 |
| Jun 12, 1982 | F3 | 23 mi | 3 mi | 0 / 0 |
| May 18, 1975 | F3 | 14 mi | 4.1 mi | 0 / 0 |
| Jun 7, 2021 | EF2 | 17 mi | 7.5 mi | 0 / 0 |
| Jun 15, 1988 | F2 | 12 mi | 0.5 mi | 0 / 0 |
| Jun 5, 1988 | F2 | 7 mi | 0.5 mi | 0 / 0 |
| Jun 5, 1988 | F2 | 7 mi | 2 mi | 0 / 0 |
| Jul 2, 1987 | F2 | 12 mi | 1 mi | 0 / 0 |
| Jun 20, 1987 | F2 | 20 mi | 1 mi | 0 / 0 |
| Jun 8, 1986 | F2 | 19 mi | 2 mi | 0 / 0 |
| Jun 8, 1986 | F2 | 13 mi | 1.1 mi | 0 / 6 |
The strongest 12 of 236, by rating and then by deaths. Ratings before February 2007 are on the original Fujita scale.
Hail in Thornton
The Storm Prediction Center has 416 hail reports within 10 miles of Thornton since 1955, made on 152 separate days. Of these, 288 were 1 inch across or larger, and 26 reached 2 inches. The largest, 3 inches (tea cup size), fell on June 13, 1984. The most recent report is from July 11, 2025. June has the most reports, 149.
Source: NOAA Storm Prediction Center severe weather reports, data through 2025.
Weather by month in Thornton
The nearest NOAA station with 1991–2020 climate normals is Northglenn, CO, 3 miles west of Thornton at 5,407 feet. July is the warmest, with an average high of 91°F and low of 59°F; December is the coolest, at 48°F and 19°F. Highs reach 90°F on about 53 days a year, almost all from May to September. Lows fall below freezing on about 149 nights a year. Snowfall averages 44.8 inches a year, most of it in March. That 14.5 inches is more than at 32 of the 91 Colorado stations used on this site (35%). Henderson, 4 miles east, has its own station (Brighton 3 SE, CO): 14.2 inches a year, 0.3 less than here, and a July average high of 90°F against 91°F.
| Month | High °F | Low °F | Precip. in | Days ≥ 0.1" | Snow in |
|---|---|---|---|---|---|
| Jan | 48 | 19 | 0.5 | 2 | 6.0 |
| Feb | 50 | 20 | 0.5 | 2 | 7.6 |
| Mar | 58 | 28 | 1.2 | 3 | 8.2 |
| Apr | 64 | 35 | 1.9 | 5 | 6.5 |
| May | 72 | 44 | 2.4 | 6 | 1.2 |
| Jun | 85 | 53 | 1.5 | 4 | 0.0 |
| Jul | 91 | 59 | 1.7 | 4 | 0.0 |
| Aug | 89 | 57 | 1.3 | 3 | 0.0 |
| Sep | 82 | 49 | 1.2 | 3 | 0.1 |
| Oct | 67 | 37 | 1.1 | 3 | 2.4 |
| Nov | 56 | 27 | 0.7 | 2 | 6.9 |
| Dec | 48 | 19 | 0.5 | 2 | 5.9 |
| Year | 67 | 37 | 14.5 | 37 | 44.8 |
Averages for 1991–2020 at Northglenn, CO (5,407 ft), from NOAA NCEI U.S. Climate Normals. Normals describe the station; the farther a place is from it, and the bigger the difference in height, the more its weather can differ.
Floods, thunderstorm wind and lightning near Thornton
Since 1996, the National Weather Service has logged 96 flood, rain, thunderstorm wind and lightning events that began within 10 miles of Thornton: 63 thunderstorm wind reports, 17 flash floods, 10 lightning strikes, 5 floods and 1 heavy rain event. They killed 1 person and injured 9, and the NWS estimated $5.0 million in property and crop damage. The strongest thunderstorm gust on record here was 97 mph, on June 18, 2013. September has had the most flash floods, 7 of 17. Of the 144 Colorado cities on this site with a flash flood on record, 120 have had fewer than Thornton.
July 19, 2016: lightning strike 10 miles from the centre of Thornton — 1 killed, 1 injured.
August 10, 1996: thunderstorm wind 6 miles from the centre of Thornton — 5 injured.
May 26, 2010: lightning strike 7 miles from the centre of Thornton — 1 injured.
Source: NOAA NCEI Storm Events Database, events whose starting point is on record, 1996 to June 30, 2026. Damage is the NWS estimate in the dollars of the year, not insured losses, and NWS notes that some reports are unverified.
Flood insurance claims, disaster declarations and FEMA risk ratings
Flood insurance policyholders in Thornton's 5 ZIP codes have filed 34 claims with the National Flood Insurance Program since 1981, and were paid $82,000 for buildings and contents, in the dollars of each year. 18% of the claims carry the name of a storm or flood event; the rest have no event name. Of the 56 Colorado cities on this site with 10 or more claims, 30 have fewer than Thornton.
Adams County, which includes Thornton, has been named in 12 federal disaster or emergency declarations since 1965, 7 of them major disasters (by incident: 5 floods, 2 biological emergencies, 2 snowstorms, 1 coastal storm). The latest major disaster declaration was Covid-19 Pandemic, on March 28, 2020. FEMA's National Risk Index gives Adams County a Relatively Moderate rating for natural hazard risk overall; by hazard: Very High for hail and lightning; Relatively High for tornadoes and strong wind; Relatively Moderate for inland flooding; Relatively Low for heat waves. It models the county's expected loss from all 18 hazards it covers at $130.9 million a year, the 5th highest of 64 Colorado counties; of the hazards above, the largest share, $44.5 million (34%), is from hail.
Claims: FEMA, OpenFEMA Dataset FIMA NFIP Redacted Claims – v3, summed over ZIP codes; payments in the dollars of each year, not adjusted for inflation. Declarations: Disaster Declarations Summaries – v2, by county. Retrieved October 25, 2026. 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).
Risk ratings: FEMA, National Risk Index county table, December 2025 (v1.20), retrieved October 26, 2026; ratings compare counties nationwide, are meant for planning and are no substitute for a local risk assessment. This product uses the Federal Emergency Management Agency's National Risk Index dataset API or downloadable datasets 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).
What counts as a pass, the distances and the sources: how this storm history is built.