San Francisco Airport, CA
California · Records since 1945–2026
Records for September 11
🔥 Record High
September 11, 1979
+23° from 75° normal❄ Record Low
September 11, 1951
-7° from 56° normalAll-Time Records — San Francisco Airport
First & Last Dates — San Francisco Airport
How early and how late each seasonal turning point has ever arrived, across the full period of record
Top 10 Record Highs — September 11
| # | Temp | Date |
|---|---|---|
| 🏆 | 98°F | September 11, 1979 |
| 2 | 96°F | September 11, 1983 |
| 3 | 89°F | September 11, 2003 |
| 4 | 89°F | September 11, 1974 |
| 5 | 86°F | September 11, 2017 |
| 6 | 86°F | September 11, 1988 |
| 7 | 84°F | September 11, 2010 |
| 8 | 83°F | September 11, 1982 |
| 9 | 82°F | September 11, 1998 |
| 10 | 81°F | September 11, 2019 |
Top 5 Record Lows — September 11
| # | Temp | Date |
|---|---|---|
| 🥶 | 49°F | September 11, 1951 |
| 2 | 50°F | September 11, 1970 |
| 3 | 50°F | September 11, 1962 |
| 4 | 50°F | September 11, 1961 |
| 5 | 50°F | September 11, 1948 |
Heat Wave Summary — San Francisco Airport
threshold: 79°F (90th percentile of historical Jun–Aug highs)Days ≥ 90°F Per Year
1946–2026Average Daily High by Decade
Full year · complete decades only
Longest Heat Waves — San Francisco Airport
| # | Dates | Days | Peak | Avg High | Avg Overnight Low |
|---|---|---|---|---|---|
| 🏆 | Oct 12, 2020 – Oct 21, 2020 | 10 | 94°F (Oct 16) | 85°F | 58°F |
| 2 | Jul 17, 2006 – Jul 25, 2006 | 9 | 97°F (Jul 22) | 85°F | 60°F |
| 3 | Sep 30, 2024 – Oct 7, 2024 | 8 | 98°F (Oct 6) | 90°F | 62°F |
| 4 | Jun 15, 1981 – Jun 22, 1981 | 8 | 92°F (Jun 15) | 87°F | 55°F |
| 5 | Aug 13, 2020 – Aug 19, 2020 | 7 | 99°F (Aug 14) | 87°F | 62°F |
| 6 | Sep 27, 2020 – Oct 3, 2020 | 7 | 96°F (Sep 28) | 89°F | 59°F |
| 7 | Oct 10, 1959 – Oct 16, 1959 | 7 | 87°F (Oct 13) | 84°F | 55°F |
| 8 | Aug 31, 2017 – Sep 5, 2017 | 6 | 104°F (Sep 1) | 92°F | 65°F |
| 9 | Jun 23, 1976 – Jun 28, 1976 | 6 | 97°F (Jun 24) | 95°F | 59°F |
| 10 | Sep 24, 2010 – Sep 29, 2010 | 6 | 96°F (Sep 27) | 90°F | 60°F |
Heat Waves Per Year
Warm Summer Nights (Jun–Aug)
Nights where the overnight low exceeded the 1991–2020 normal low
Above-Normal Summer Nights Per Year
Average June–August Low by Decade
Overnight lows · complete decades only
Precipitation
Annual totals and trend across the full period of record · see this year's standing →
Monthly Precipitation — Last 24 Months
Blue = actual · dashed line = monthly normal
Annual Precipitation Per Year (1945–2026)
Blue = above average · tan = below average · gold = 2026 (partial)
Since 1945, annual totals have trended
+0.17" per decade,
about +1.3"
across the record.
Heavy Rain Days Per Year (≥ 1.0")
Compare year-to-year changes in days with heavy rainfall (≥ 1.0")
This Year — 2026
How San Francisco Airport is tracking against normal, year to date
Daily High Temperature vs Normal
110 of 253 days with data were above the 1991–2020 normal high for their date.
Precipitation, Year to Date
Accumulation vs. Normal
Running total since Jan 1 against the normal pace for the same date · San Francisco Airport is 1.83" behind the normal pace
Period Review — Sep 1 – Sep 10, 2026
Any window, evaluated against every other year on record — 10 days
Average Temperature by Year — Sep 1 – Sep 10
1945–2026 · 2026 highlighted · trend +0.50° per decade (warming since 1945)
Precipitation by Year — Sep 1 – Sep 10
1945–2025 · 2026 highlighted
Warmest Sep 1 – Sep 10 on Record
| # | Year | Avg Temp |
|---|---|---|
| 1 | 2017 | 74.7°F |
| 2 | 2022 | 72.0°F |
| 3 | 2004 | 71.8°F |
| 4 | 1984 | 71.1°F |
| 5 | 1958 | 69.6°F |
| 6 | 2015 | 69.3°F |
| 7 | 2008 | 69.2°F |
| 8 | 1983 | 69.1°F |
| 9 | 2020 | 69.0°F |
| 10 | 2026 | 68.8°F |
Coolest Sep 1 – Sep 10 on Record
| # | Year | Avg Temp |
|---|---|---|
| 1 | 1962 | 59.2°F |
| 2 | 1946 | 59.6°F |
| 3 | 1948 | 60.3°F |
| 4 | 1965 | 60.5°F |
| 5 | 2006 | 60.6°F |
| 6 | 1954 | 60.6°F |
| 7 | 1989 | 60.9°F |
| 8 | 2012 | 61.1°F |
| 9 | 1964 | 61.4°F |
| 10 | 1980 | 61.7°F |