NHC HURDAT2 · SPC Tornado Database
Hurricanes and Tornadoes That Hit Longmont, 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 Longmont, Colorado since records began in 1851. Since 1950, 132 tornadoes have touched down within 25 miles, 2 of them rated EF3 or stronger.
- Hurricanes
- 0
- Tropical storms
- 0
- Tornadoes
- 132
- EF3 or stronger
- 2
within 75 mi, since 1851
below hurricane strength
within 25 mi, since 1950
1 deaths in all
What the records show for Longmont
The highest rating among the 132 tornadoes within 25 miles is EF3, reached 2 times; the most recent, on June 4, 2015, came within 6 miles. The deadliest, an EF3 on May 22, 2008, killed 1 person. Of the 132, 5 had paths within 5 miles of the city centre, and 37 have come since 2000. June has had the most tornadoes, 54. The most recent tornado was on June 13, 2025. Longmont has more tornadoes within 25 miles than 64% of the 157 Colorado cities on this site. Hail has been reported within 10 miles 255 times since 1962, with stones up to 2.75 inches (baseball size). Longmont has more hail reports within 10 miles than 77% of the 157 Colorado cities.
Compare Longmont's storm record with another city →
Tornadoes within 25 miles of Longmont
By decade
- 2020s4
- 2010s9(1 EF3+)
- 2000s24(1 EF3+)
- 1990s36
- 1980s29
- 1970s14
- 1960s7
- 1950s9
| Date | Rating | Distance | Path | Killed / injured |
|---|---|---|---|---|
| May 22, 2008 | EF3 | 18 mi | 38.69 mi | 1 / 78 |
| Jun 4, 2015 | EF3 | 6 mi | 6.71 mi | 0 / 0 |
| Jun 7, 2021 | EF2 | 10 mi | 7.5 mi | 0 / 0 |
| Jun 5, 1988 | F2 | 15 mi | 0.5 mi | 0 / 0 |
| Jun 5, 1988 | F2 | 11 mi | 2 mi | 0 / 0 |
| May 18, 1984 | F2 | 22 mi | 5 mi | 0 / 0 |
| Jun 3, 1981 | F2 | 21 mi | 2.3 mi | 0 / 42 |
| Oct 15, 1980 | F2 | 12 mi | 1.5 mi | 0 / 0 |
| Jun 4, 1976 | F2 | 14 mi | 1.5 mi | 0 / 0 |
| Jun 8, 1958 | F2 | 21 mi | 7.1 mi | 0 / 0 |
| May 30, 1957 | F2 | 23 mi | 1.3 mi | 0 / 1 |
| May 30, 1957 | F2 | 23 mi | 9.1 mi | 0 / 0 |
The strongest 12 of 132, by rating and then by deaths. Ratings before February 2007 are on the original Fujita scale.
Hail in Longmont
The Storm Prediction Center has 255 hail reports within 10 miles of Longmont since 1962, made on 100 separate days. Of these, 173 were 1 inch across or larger, and 9 reached 2 inches. The largest, 2.75 inches (baseball size), fell on May 25, 1962. The most recent report is from August 10, 2025. May has the most reports, 72.
Source: NOAA Storm Prediction Center severe weather reports, data through 2025.
Weather by month in Longmont
The nearest NOAA station with 1991–2020 climate normals is Longmont 2 ESE, CO, in Longmont at 4,950 feet. July is the warmest, with an average high of 91°F and low of 55°F; January is the coolest, at 45°F and 14°F. Highs reach 90°F on about 49 days a year, almost all from May to September. Lows fall below freezing on about 178 nights a year. That 15.5 inches is more than at 45 of the 91 Colorado stations used on this site (49%). Lafayette, 11 miles south, has its own station (Northglenn, CO): 14.5 inches a year, 1.0 less than here, and the same July average high, 91°F.
| Month | High °F | Low °F | Precip. in | Days ≥ 0.1" |
|---|---|---|---|---|
| Jan | 45 | 14 | 0.6 | 2 |
| Feb | 47 | 17 | 0.6 | 2 |
| Mar | 57 | 26 | 1.2 | 3 |
| Apr | 63 | 32 | 2.0 | 5 |
| May | 73 | 41 | 2.0 | 6 |
| Jun | 84 | 51 | 1.8 | 5 |
| Jul | 91 | 55 | 1.7 | 3 |
| Aug | 88 | 54 | 2.0 | 3 |
| Sep | 80 | 46 | 1.3 | 4 |
| Oct | 66 | 33 | 1.0 | 3 |
| Nov | 54 | 24 | 0.8 | 3 |
| Dec | 45 | 15 | 0.5 | 1 |
| Year | 66 | 34 | 15.5 | 40 |
Averages for 1991–2020 at Longmont 2 ESE, CO (4,950 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 Longmont
Since 1996, the National Weather Service has logged 40 flood, rain, thunderstorm wind and lightning events that began within 10 miles of Longmont: 27 thunderstorm wind reports, 9 flash floods, 2 lightning strikes, 1 flood and 1 heavy rain event. They killed 3 people and injured 0, and the NWS estimated $25,000 in property and crop damage. The strongest thunderstorm gust on record here was 81 mph, on July 25, 2018. September has had the most flash floods, 8 of 9. Of the 144 Colorado cities on this site with a flash flood on record, 86 have had fewer than Longmont.
September 12, 2013: flash flood 8 miles from the centre of Longmont — 2 killed.
September 11, 2013: flash flood 5 miles from the centre of Longmont — 1 killed.
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 Longmont's 3 ZIP codes have filed 142 claims with the National Flood Insurance Program since 1979, and were paid $7.1 million for buildings and contents, in the dollars of each year. The most came from Late summer storms in 2013: 114 claims (80% of all) and $7.0 million. 80% 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, 49 have fewer than Longmont.
| Event | Claims | Paid |
|---|---|---|
| Late summer storms2013 | 114 | $7.0 million |
Boulder County, which includes Longmont, has been named in 19 federal disaster or emergency declarations since 1969, 7 of them major disasters (by incident: 9 fires, 5 floods, 2 biological emergencies, 2 snowstorms). The latest major disaster declaration was Wildfires and Straight-Line Winds, on December 31, 2021. FEMA's National Risk Index gives Boulder County a Relatively Moderate rating for natural hazard risk overall; by hazard: Very High for lightning; Relatively High for tornadoes, hail 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 $125.3 million a year, the 7th highest of 64 Colorado counties; of the hazards above, the largest share, $69.1 million (55%), is from inland flooding.
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.