NHC HURDAT2 · SPC Tornado Database
Hurricanes and Tornadoes That Hit Alamo, CA
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 Alamo, California since records began in 1851. Since 1950, 10 tornadoes have touched down within 25 miles, 0 of them rated EF3 or stronger.
- Hurricanes
- 0
- Tropical storms
- 0
- Tornadoes
- 10
- EF3 or stronger
- 0
within 75 mi, since 1851
below hurricane strength
within 25 mi, since 1950
no recorded deaths
What the records show for Alamo
The highest rating among the 10 tornadoes within 25 miles is F1 or EF1, reached 2 times; the most recent, on January 23, 2010, came within 15 miles. Of the 10, none had a path within 5 miles of the city centre, and one has come since 2000. Of the 705 California cities on this site, 59% have more tornadoes within 25 miles than Alamo. Hail has been reported within 10 miles 10 times since 2018, with stones up to 0.5 inches (marble size). Alamo has more hail reports within 10 miles than 88% of the 705 California cities.
Compare Alamo's storm record with another city →
Tornadoes within 25 miles of Alamo
By decade
- 2010s1
- 1990s5
- 1980s3
- 1950s1
| Date | Rating | Distance | Path | Killed / injured |
|---|---|---|---|---|
| Jan 23, 2010 | EF1 | 15 mi | 1.64 mi | 0 / 0 |
| Apr 1, 1958 | F1 | 24 mi | 0.2 mi | 0 / 0 |
| Dec 5, 1998 | F0 | 18 mi | 1.5 mi | 0 / 0 |
| May 12, 1998 | F0 | 24 mi | 0.2 mi | 0 / 0 |
| Feb 19, 1998 | F0 | 18 mi | 0.2 mi | 0 / 0 |
| Apr 25, 1994 | F0 | 19 mi | 0.7 mi | 0 / 0 |
| Dec 17, 1992 | F0 | 11 mi | 0.2 mi | 0 / 0 |
| Sep 18, 1989 | F0 | 8 mi | 0.2 mi | 0 / 0 |
| Sep 18, 1989 | F0 | 8 mi | 0.2 mi | 0 / 0 |
| Mar 29, 1982 | F0 | 19 mi | 0.1 mi | 0 / 0 |
The strongest 10 of 10, by rating and then by deaths. Ratings before February 2007 are on the original Fujita scale.
Hail in Alamo
The Storm Prediction Center has 10 hail reports within 10 miles of Alamo since 2018, made on 7 separate days. None of them reached 1 inch. The largest, 0.5 inches (marble size), fell on March 3, 2018. The most recent report is from March 30, 2024. March has the most reports, 4.
Source: NOAA Storm Prediction Center severe weather reports, data through 2025.
Weather by month in Alamo
The nearest NOAA station with 1991–2020 climate normals is Mt Diablo Junction, CA, 5 miles east of Alamo at 2,170 feet. July is the warmest, with an average high of 83°F and low of 62°F; December is the coolest, at 53°F and 41°F. January and December are the wettest at 5.1 inches of precipitation on average and July and August the driest at 0.0 inches; the year adds up to 26.1 inches over 45 days with at least a tenth of an inch. Highs reach 90°F on about 27 days a year, almost all from June to October. Lows fall below freezing on about 19 nights a year. Snowfall averages 0.7 inches a year, most of it in February. That 26.1 inches is more than at 173 of the 226 California stations used on this site (77%). Moraga, 6 miles west, has its own station (Berkeley, CA): 26.0 inches a year, the same as here, and a July average high of 74°F against 83°F.
Water temperature at the NOAA tide station Martinez-Amorco Pier, CA, 14 miles northwest, averaged 71°F in August and 51°F in January over 2021–2025. No month averaged 80°F. Sea level at the Port Chicago tide gauge, 14 miles from Alamo, has risen 0.77 ± 0.23 inches per decade from 1976 to 2025, NOAA's linear trend; at that pace it is 7.7 inches in a hundred years. That is faster than at 36 of the 144 U.S. gauges with a NOAA trend.
| Month | High °F | Low °F | Precip. in | Days ≥ 0.1" | Snow in | Water °F |
|---|---|---|---|---|---|---|
| Jan | 54 | 42 | 5.1 | 8 | 0.1 | 51 |
| Feb | 55 | 42 | 4.9 | 8 | 0.5 | 53 |
| Mar | 58 | 43 | 3.7 | 7 | 0.1 | 55 |
| Apr | 62 | 44 | 1.9 | 4 | 0.0 | 60 |
| May | 68 | 49 | 1.1 | 2 | 0.0 | 64 |
| Jun | 76 | 55 | 0.3 | 1 | 0.0 | 67 |
| Jul | 83 | 62 | 0.0 | 0 | 0.0 | 69 |
| Aug | 83 | 61 | 0.0 | 0 | 0.0 | 71 |
| Sep | 80 | 60 | 0.1 | 0 | 0.0 | 69 |
| Oct | 72 | 54 | 1.2 | 2 | 0.0 | 66 |
| Nov | 60 | 46 | 2.7 | 5 | 0.0 | 59 |
| Dec | 53 | 41 | 5.1 | 8 | 0.0 | 53 |
| Year | 67 | 50 | 26.1 | 45 | 0.7 | 61 |
Averages for 1991–2020 at Mt Diablo Junction, CA (2,170 ft), from NOAA NCEI U.S. Climate Normals; water temperature: average of hourly readings 2021–2025 at the NOAA tide station Martinez-Amorco Pier, CA, from NOAA Tides & Currents. 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 Alamo
Since 1996, the National Weather Service has logged 37 flood, rain, thunderstorm wind and lightning events that began within 10 miles of Alamo: 30 floods, 3 heavy rain events, 3 thunderstorm wind reports and 1 lightning strike. They killed 2 people and injured 1, and the NWS estimated $314,000 in property and crop damage. The strongest thunderstorm gust on record here was 63 mph, on August 16, 2020.
April 11, 2010: heavy rain event 3 miles from the centre of Alamo — 2 killed, 1 injured, $10,000 damage.
December 2, 2012: flood 8 miles from the centre of Alamo — $250,000 damage.
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 Alamo's ZIP code 94507 have filed 31 claims with the National Flood Insurance Program since 1982, and were paid $160,000 for buildings and contents, in the dollars of each year. 29% of the claims carry the name of a storm or flood event; the rest have no event name. Of the 415 California cities on this site with 10 or more claims, 159 have fewer than Alamo.
Contra Costa County, which includes Alamo, has been named in 21 federal disaster or emergency declarations since 1969, 16 of them major disasters (by incident: 8 floods, 6 severe storms, 2 biological emergencies, 2 coastal storms). The latest major disaster declaration was Severe Winter Storms, Flooding, Landslides, and Mudslides, on January 14, 2023. FEMA's National Risk Index gives Contra Costa County a Very High rating for natural hazard risk overall; by hazard: Very High for inland flooding; Relatively High for lightning and heat waves; Relatively Moderate for coastal flooding; Relatively Low for tornadoes and strong wind; Very Low for hail. It models the county's expected loss from all 18 hazards it covers at $970.5 million a year, the 8th highest of 58 California counties; of the hazards above, the largest share, $412.5 million (42%), 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.