NHC HURDAT2 · SPC Tornado Database
Hurricanes and Tornadoes That Hit San Lorenzo, 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 San Lorenzo, California since records began in 1851. Since 1950, 15 tornadoes have touched down within 25 miles, 0 of them rated EF3 or stronger.
- Hurricanes
- 0
- Tropical storms
- 0
- Tornadoes
- 15
- 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 San Lorenzo
The highest rating among the 15 tornadoes within 25 miles is F2, reached 2 times; the most recent, on May 5, 1998, came within 22 miles. Of the 15, one had a path within 5 miles of the city centre, and one has come since 2000. March has had the most tornadoes, 3. The most recent tornado was on March 20, 2005. San Lorenzo has more tornadoes within 25 miles than 52% of the 705 California cities on this site. Hail has been reported within 10 miles 7 times since 1999, with stones up to 0.75 inches (penny size). San Lorenzo has more hail reports within 10 miles than 76% of the 705 California cities.
Compare San Lorenzo's storm record with another city →
Tornadoes within 25 miles of San Lorenzo
By decade
- 2000s1
- 1990s7
- 1980s5
- 1950s2
| Date | Rating | Distance | Path | Killed / injured |
|---|---|---|---|---|
| May 5, 1998 | F2 | 22 mi | 0.6 mi | 0 / 1 |
| Jan 11, 1951 | F2 | 19 mi | 5.7 mi | 0 / 0 |
| Mar 20, 2005 | F1 | 16 mi | 3 mi | 0 / 0 |
| May 5, 1998 | F1 | 21 mi | 0.3 mi | 0 / 1 |
| Jan 14, 1980 | F1 | 19 mi | 0.3 mi | 0 / 1 |
| Apr 1, 1958 | F1 | 13 mi | 0.2 mi | 0 / 0 |
| Dec 5, 1998 | F0 | 21 mi | 1.5 mi | 0 / 0 |
| Feb 7, 1998 | F0 | 22 mi | 0.2 mi | 0 / 0 |
| Feb 6, 1998 | F0 | 22 mi | 0.1 mi | 0 / 0 |
| Apr 25, 1994 | F0 | 20 mi | 0.7 mi | 0 / 0 |
| Dec 17, 1992 | F0 | 4 mi | 0.2 mi | 0 / 0 |
| Sep 18, 1989 | F0 | 21 mi | 0.2 mi | 0 / 0 |
The strongest 12 of 15, by rating and then by deaths. Ratings before February 2007 are on the original Fujita scale.
Hail in San Lorenzo
The Storm Prediction Center has 7 hail reports within 10 miles of San Lorenzo since 1999, made on 5 separate days. None of them reached 1 inch. The largest, 0.75 inches (penny size), fell on February 9, 1999. The most recent report is from November 27, 2019.
Source: NOAA Storm Prediction Center severe weather reports, data through 2025.
Weather by month in San Lorenzo
The nearest NOAA station with 1991–2020 climate normals is Hayward Air Terminal, CA, 2 miles southeast of San Lorenzo at 43 feet. August is the warmest, with an average high of 76°F and low of 58°F; December is the coolest, at 59°F and 43°F. December is the wettest at 3.2 inches of precipitation on average and July the driest at 0.0 inches; the year adds up to 16.1 inches over 35 days with at least a tenth of an inch. Highs reach 90°F on about 9 days a year, almost all from June to September. Lows fall below freezing on about 1 nights a year. That 16.1 inches is more than at 113 of the 226 California stations used on this site (50%). Union City, 8 miles southeast, has its own station (Fremont, CA): 16.0 inches a year, 0.1 less than here, and an August average high of 78°F against 76°F.
Water temperature at the NOAA tide station Alameda, CA, 11 miles northwest, averaged 69°F in August and 53°F in January over 2021–2025. No month averaged 80°F. Sea level at the Alameda tide gauge, 11 miles from San Lorenzo, has risen 0.37 ± 0.07 inches per decade from 1939 to 2025, NOAA's linear trend; at that pace it is 3.7 inches in a hundred years. That is faster than at 21 of the 144 U.S. gauges with a NOAA trend.
| Month | High °F | Low °F | Precip. in | Days ≥ 0.1" | Water °F |
|---|---|---|---|---|---|
| Jan | 59 | 43 | 2.9 | 5 | 53 |
| Feb | 62 | 45 | 3.1 | 7 | 54 |
| Mar | 64 | 47 | 2.4 | 6 | 57 |
| Apr | 67 | 50 | 1.2 | 3 | 61 |
| May | 69 | 52 | 0.6 | 1 | 64 |
| Jun | 74 | 55 | 0.2 | 0 | 67 |
| Jul | 75 | 57 | 0.0 | 0 | 68 |
| Aug | 76 | 58 | 0.1 | 0 | 69 |
| Sep | 77 | 58 | 0.1 | 0 | 69 |
| Oct | 74 | 54 | 0.8 | 2 | 65 |
| Nov | 65 | 47 | 1.5 | 4 | 59 |
| Dec | 59 | 43 | 3.2 | 6 | 54 |
| Year | 68 | 51 | 16.1 | 35 | 62 |
Averages for 1991–2020 at Hayward Air Terminal, CA (43 ft), from NOAA NCEI U.S. Climate Normals; water temperature: average of hourly readings 2021–2025 at the NOAA tide station Alameda, 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 San Lorenzo
Since 1996, the National Weather Service has logged 47 flood, rain, thunderstorm wind and lightning events that began within 10 miles of San Lorenzo: 39 floods, 6 heavy rain events, 1 flash flood and 1 thunderstorm wind report. They killed 2 people and injured 7, and the NWS estimated $26,000 in property and crop damage. The strongest thunderstorm gust on record here was 59 mph, on December 14, 2024.
November 1, 2008: heavy rain event 6 miles from the centre of San Lorenzo — 1 killed, 5 injured, $15,000 damage.
March 10, 2023: flood 6 miles from the centre of San Lorenzo — 1 killed, 1 injured.
March 10, 2023: heavy rain event 6 miles from the centre of San Lorenzo — 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
Alameda County, which includes San Lorenzo, has been named in 24 federal disaster or emergency declarations since 1970, 20 of them major disasters (by incident: 8 severe storms, 7 floods, 2 biological emergencies, 2 fires). The latest major disaster declaration was Severe Winter Storms, Straight-Line Winds, Flooding, Landslides, and Mudslides, on April 3, 2023. FEMA's National Risk Index gives Alameda County a Very High rating for natural hazard risk overall; by hazard: Very High for inland flooding; Relatively High for coastal flooding and heat waves; Relatively Moderate for tornadoes; Relatively Low for hail and lightning; Very Low for strong wind. It models the county's expected loss from all 18 hazards it covers at $1.88 billion a year, the 6th highest of 58 California counties; of the hazards above, the largest share, $490.5 million (26%), 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.