Palo Alto Weather Records (MXN00001015)
Record envelope, standing records and threshold days for Palo Alto (MXN00001015), Mexico, with 47 years of record.
Key Facts for Palo Alto
- Palo Alto (MXN00001015) is a weather station in Mexico at 21.90 latitude and -101.97 longitude, 2,037 m (6,684 ft) above sea level.
- The station reports from 1967 to 2013, 47 years of record.
- 1,464 records set at Palo Alto still stand.
- Records are tracked for tmax, tmin, prcp: an element needs 30 years of data to be eligible.
- Palo Alto set a daily record high minimum temperature of 15.6 C (60.1 F) on 24 September 2013.
About the Station
- Location: Mexico, 21.90 latitude, -101.97 longitude.
- Elevation: 2,037 m (6,684 ft).
- Period of record: 1967 to 2013, 47 years.
- Eligible elements: tmax, tmin, prcp.
Daily Record Envelope and 2026
0 days at or beyond a record| Month | Highest record high | Lowest record low | 2026 highest maximum | 2026 lowest minimum |
|---|---|---|---|---|
| Jan | 28.9 C (84.0 F) | -9.4 C (15.1 F) | n/a | n/a |
| Feb | 31.7 C (89.1 F) | -7.2 C (19.0 F) | n/a | n/a |
| Mar | 35.0 C (95.0 F) | -4.4 C (24.1 F) | n/a | n/a |
| Apr | 38.9 C (102.0 F) | 0.0 C (32.0 F) | n/a | n/a |
| May | 37.8 C (100.0 F) | 3.9 C (39.0 F) | n/a | n/a |
| Jun | 37.8 C (100.0 F) | 5.6 C (42.1 F) | n/a | n/a |
| Jul | 35.6 C (96.1 F) | 6.7 C (44.1 F) | n/a | n/a |
| Aug | 33.9 C (93.0 F) | 7.8 C (46.0 F) | n/a | n/a |
| Sep | 32.8 C (91.0 F) | 2.8 C (37.0 F) | n/a | n/a |
| Oct | 32.8 C (91.0 F) | -2.2 C (28.0 F) | n/a | n/a |
| Nov | 30.6 C (87.1 F) | -7.2 C (19.0 F) | n/a | n/a |
| Dec | 30.0 C (86.0 F) | -9.4 C (15.1 F) | n/a | n/a |
Which Years Hold Standing Records
1,464 standing records| Year set | Standing records |
|---|---|
| 1970 | 28 |
| 1971 | 45 |
| 1972 | 65 |
| 1973 | 45 |
| 1974 | 34 |
| 1975 | 32 |
| 1976 | 38 |
| 1977 | 29 |
| 1978 | 42 |
| 1979 | 54 |
| 1980 | 49 |
| 1981 | 40 |
| 1982 | 30 |
| 1983 | 27 |
| 1984 | 32 |
| 1985 | 24 |
| 1986 | 32 |
| 1987 | 50 |
| 1988 | 34 |
| 1989 | 36 |
| 1990 | 32 |
| 1991 | 32 |
| 1992 | 48 |
| 1993 | 17 |
| 1994 | 11 |
| 1995 | 33 |
| 1996 | 30 |
| 1997 | 31 |
| 1998 | 58 |
| 1999 | 29 |
| 2000 | 31 |
| 2001 | 29 |
| 2002 | 16 |
| 2003 | 39 |
| 2004 | 19 |
| 2005 | 29 |
| 2006 | 22 |
| 2007 | 15 |
| 2008 | 29 |
| 2009 | 71 |
| 2010 | 31 |
| 2011 | 22 |
| 2012 | 9 |
| 2013 | 15 |
All-Time Record Progression
2 new records| Date | Kind | Detail |
|---|---|---|
| 2002-04-20 | Record high maximum temperature | Record high maximum temperature 38.9 C (102.0 F) |
| 2004-06-23 | Record daily precipitation | Record daily precipitation 85.3 mm (3.4 in) |
Wettest Day of Each Month
Jun: 85.3 mm (3.4 in)| Month | Record daily precipitation (mm) | Date |
|---|---|---|
| Jan | 60.5 mm (2.4 in) | 12 January 2002 |
| Feb | 66.8 mm (2.6 in) | 3 February 2010 |
| Mar | 39.9 mm (1.6 in) | 4 March 1968 |
| Apr | 26.4 mm (1.0 in) | 16 April 1981 |
| May | 51.8 mm (2.0 in) | 14 May 2013 |
| Jun | 85.3 mm (3.4 in) | 23 June 2004 |
| Jul | 78.5 mm (3.1 in) | 5 July 2008 |
| Aug | 82.3 mm (3.2 in) | 11 August 1978 |
| Sep | 78.0 mm (3.1 in) | 2 September 2011 |
| Oct | 52.8 mm (2.1 in) | 15 October 1973 |
| Nov | 49.3 mm (1.9 in) | 3 November 2002 |
| Dec | 27.7 mm (1.1 in) | 2 December 1979 |
Period of Record Coverage
1970 to 2013| Year | Days with data | Share of year | Complete |
|---|---|---|---|
| 1970 | 146 | 40% | No |
| 1971 | 365 | 100% | Yes |
| 1972 | 366 | 100% | Yes |
| 1973 | 365 | 100% | Yes |
| 1974 | 365 | 100% | Yes |
| 1975 | 365 | 100% | Yes |
| 1976 | 366 | 100% | Yes |
| 1977 | 365 | 100% | Yes |
| 1978 | 365 | 100% | Yes |
| 1979 | 365 | 100% | Yes |
| 1980 | 366 | 100% | Yes |
| 1981 | 364 | 100% | Yes |
| 1982 | 334 | 92% | Yes |
| 1983 | 334 | 92% | Yes |
| 1984 | 366 | 100% | Yes |
| 1985 | 365 | 100% | Yes |
| 1986 | 365 | 100% | Yes |
| 1987 | 365 | 100% | Yes |
| 1988 | 366 | 100% | Yes |
| 1989 | 365 | 100% | Yes |
| 1990 | 334 | 92% | Yes |
| 1991 | 365 | 100% | Yes |
| 1992 | 366 | 100% | Yes |
| 1993 | 365 | 100% | Yes |
| 1994 | 365 | 100% | Yes |
| 1995 | 365 | 100% | Yes |
| 1996 | 366 | 100% | Yes |
| 1997 | 365 | 100% | Yes |
| 1998 | 365 | 100% | Yes |
| 1999 | 365 | 100% | Yes |
| 2000 | 366 | 100% | Yes |
| 2001 | 365 | 100% | Yes |
| 2002 | 365 | 100% | Yes |
| 2003 | 364 | 100% | Yes |
| 2004 | 365 | 100% | Yes |
| 2005 | 365 | 100% | Yes |
| 2006 | 365 | 100% | Yes |
| 2007 | 365 | 100% | Yes |
| 2008 | 366 | 100% | Yes |
| 2009 | 365 | 100% | Yes |
| 2010 | 365 | 100% | Yes |
| 2011 | 365 | 100% | Yes |
| 2012 | 365 | 100% | Yes |
| 2013 | 273 | 75% | No |
Latest Records
20| Date | Station | Record | Value | Beat old record by | Old record stood | Significance |
|---|---|---|---|---|---|---|
| 24 September 2013 | Palo Alto, MX | daily high min | 15.6 C (60.1 F) | 0.6 C (1.1 F) | 35 years | 16 of 100 (Routine) |
| 23 September 2013 | Palo Alto, MX | daily high min (Tie) | 15.0 C (59.0 F) | tie | 20 years | 2 of 100 (Routine) |
| 22 September 2013 | Palo Alto, MX | daily high min (Tie) | 15.0 C (59.0 F) | tie | 24 years | 2 of 100 (Routine) |
| 21 September 2013 | Palo Alto, MX | daily high min (Tie) | 15.0 C (59.0 F) | tie | 10 years | 1 of 100 (Routine) |
| 20 September 2013 | Palo Alto, MX | daily high min (Tie) | 15.6 C (60.1 F) | tie | 3 years | 1 of 100 (Routine) |
| 19 September 2013 | Palo Alto, MX | daily high min (Tie) | 15.6 C (60.1 F) | tie | 15 years | 2 of 100 (Routine) |
| 18 September 2013 | Palo Alto, MX | daily high min (Tie) | 15.0 C (59.0 F) | tie | 15 years | 2 of 100 (Routine) |
| 17 September 2013 | Palo Alto, MX | daily high min (Tie) | 13.9 C (57.0 F) | tie | 42 years | 4 of 100 (Routine) |
| 16 September 2013 | Palo Alto, MX | daily high min (Tie) | 15.0 C (59.0 F) | tie | 15 years | 2 of 100 (Routine) |
| 12 September 2013 | Palo Alto, MX | daily high min (Tie) | 15.0 C (59.0 F) | tie | 40 years | 4 of 100 (Routine) |
| 8 September 2013 | Palo Alto, MX | daily high min | 15.6 C (60.1 F) | 0.6 C (1.1 F) | 36 years | 16 of 100 (Routine) |
| 7 September 2013 | Palo Alto, MX | daily high min (Tie) | 15.0 C (59.0 F) | tie | 22 years | 2 of 100 (Routine) |
| 31 August 2013 | Palo Alto, MX | daily high max (Tie) | 30.0 C (86.0 F) | tie | 40 years | 4 of 100 (Routine) |
| 22 August 2013 | Palo Alto, MX | daily rain | 33.8 mm (1.3 in) | 8.1 mm (0.32 in) | 32 years | 19 of 100 (Routine) |
| 21 August 2013 | Palo Alto, MX | daily rain | 42.9 mm (1.7 in) | 7.1 mm (0.28 in) | 14 years | 13 of 100 (Routine) |
| 11 August 2013 | Palo Alto, MX | daily high min (Tie) | 15.0 C (59.0 F) | tie | 40 years | 4 of 100 (Routine) |
| 9 August 2013 | Palo Alto, MX | daily high max (Tie) | 30.6 C (87.1 F) | tie | 32 years | 3 of 100 (Routine) |
| 8 August 2013 | Palo Alto, MX | daily high max (Tie) | 30.0 C (86.0 F) | tie | 32 years | 3 of 100 (Routine) |
| 8 August 2013 | Palo Alto, MX | daily high min (Tie) | 15.6 C (60.1 F) | tie | 18 years | 2 of 100 (Routine) |
| 20 July 2013 | Palo Alto, MX | daily high min (Tie) | 15.0 C (59.0 F) | tie | 30 years | 3 of 100 (Routine) |
Climate Trend
39 complete years, 1971 to 2012| Year | Annual mean temperature | Difference from the station mean |
|---|---|---|
| 1971 | 17.3 C | +0.23 C |
| 1972 | 17.9 C | +0.78 C |
| 1973 | 17.1 C | +0.04 C |
| 1974 | 17.1 C | +0.04 C |
| 1975 | 17.2 C | +0.13 C |
| 1976 | 16.8 C | -0.34 C |
| 1977 | 16.6 C | -0.47 C |
| 1978 | 16.7 C | -0.37 C |
| 1979 | 16.5 C | -0.60 C |
| 1980 | 17.2 C | +0.11 C |
| 1981 | 16.9 C | -0.25 C |
| 1984 | 16.4 C | -0.69 C |
| 1985 | 16.6 C | -0.52 C |
| 1986 | 16.8 C | -0.34 C |
| 1987 | 16.6 C | -0.52 C |
| 1988 | 16.8 C | -0.29 C |
| 1989 | 16.6 C | -0.46 C |
| 1991 | 16.8 C | -0.30 C |
| 1992 | 16.3 C | -0.79 C |
| 1993 | 17.1 C | -0.03 C |
| 1994 | 17.6 C | +0.50 C |
| 1995 | 17.5 C | +0.43 C |
| 1996 | 17.4 C | +0.29 C |
| 1997 | 16.9 C | -0.21 C |
| 1998 | 17.7 C | +0.63 C |
| 1999 | 17.2 C | +0.14 C |
| 2000 | 17.5 C | +0.35 C |
| 2001 | 17.3 C | +0.17 C |
| 2002 | 17.4 C | +0.34 C |
| 2003 | 17.6 C | +0.45 C |
| 2004 | 16.7 C | -0.39 C |
| 2005 | 17.1 C | -0.05 C |
| 2006 | 17.1 C | +0.02 C |
| 2007 | 17.1 C | -0.03 C |
| 2008 | 16.8 C | -0.28 C |
| 2009 | 18.5 C | +1.35 C |
| 2010 | 16.4 C | -0.71 C |
| 2011 | 17.9 C | +0.84 C |
| 2012 | 17.9 C | +0.82 C |
The fitted trend in annual mean temperature here over 1971 to 2012 is 0.12 C (0.00 to 0.24) per decade. The interval includes zero, so the trend is not clearly different from zero. In Fahrenheit: 0.22 F (-0.01 to 0.44) per decade. The slope is a straight line fitted to 39 complete years; the brackets give its 95 percent interval.
| Measure | Per decade (C) | Per decade (F) | Period | Complete years | Reading |
|---|---|---|---|---|---|
| Annual mean temperature | 0.12 C (0.00 to 0.24) per decade | 0.22 F (-0.01 to 0.44) per decade | 1971 to 2012 | 39 | Not clearly different from zero |
| Mean daily maximum | 0.5 C (0.2 to 0.7) per decade | 0.8 F (0.4 to 1.3) per decade | 1971 to 2012 | 39 | Rise |
| Mean daily minimum | -0.2 C (-0.3 to -0.1) per decade | -0.4 F (-0.6 to -0.2) per decade | 1971 to 2012 | 39 | Fall |
A year is complete when all 12 months have at least 20 days of both daily maximum and daily minimum readings. The annual mean is the mean of the monthly means. The trend describes this one station over this period; it does not say what caused the change.
Extremes by Year
1967 to 2013| Measure | Record | Year of the record | Median year | Years with a value |
|---|---|---|---|---|
| Hottest day (TXx) | 38.9 C (102.0 F) | 2002 | 35.0 C (95.0 F) | 44 |
| Coldest night (TNn) | -9.4 C (15.1 F) | 1997 | -4.4 C (24.1 F) | 44 |
| Wettest day (Rx1day) | 85.3 mm (3.4 in) | 2004 | 47.0 mm (1.9 in) | 47 |
| Wettest five days (Rx5day) | 177.8 mm (7.0 in) | 2008 | 90.2 mm (3.6 in) | 47 |
| Longest dry spell (CDD) | 171 days | 2011 | 93 days | 47 |
Hottest day (TXx)
| Year | Hottest day (TXx) |
|---|---|
| 1967 | n/a |
| 1968 | n/a |
| 1969 | n/a |
| 1970 | 30.0 C (86.0 F) |
| 1971 | 35.0 C (95.0 F) |
| 1972 | 35.6 C (96.1 F) |
| 1973 | 35.6 C (96.1 F) |
| 1974 | 33.9 C (93.0 F) |
| 1975 | 35.0 C (95.0 F) |
| 1976 | 33.9 C (93.0 F) |
| 1977 | 32.2 C (90.0 F) |
| 1978 | 32.8 C (91.0 F) |
| 1979 | 31.7 C (89.1 F) |
| 1980 | 33.9 C (93.0 F) |
| 1981 | 33.9 C (93.0 F) |
| 1982 | 35.6 C (96.1 F) |
| 1983 | 35.6 C (96.1 F) |
| 1984 | 32.8 C (91.0 F) |
| 1985 | 33.9 C (93.0 F) |
| 1986 | 35.0 C (95.0 F) |
| 1987 | 31.7 C (89.1 F) |
| 1988 | 33.9 C (93.0 F) |
| 1989 | 35.0 C (95.0 F) |
| 1990 | 35.0 C (95.0 F) |
| 1991 | 35.0 C (95.0 F) |
| 1992 | 31.7 C (89.1 F) |
| 1993 | 33.9 C (93.0 F) |
| 1994 | 33.9 C (93.0 F) |
| 1995 | 35.6 C (96.1 F) |
| 1996 | 35.6 C (96.1 F) |
| 1997 | 32.8 C (91.0 F) |
| 1998 | 36.7 C (98.1 F) |
| 1999 | 33.9 C (93.0 F) |
| 2000 | 35.0 C (95.0 F) |
| 2001 | 35.6 C (96.1 F) |
| 2002 | 38.9 C (102.0 F) |
| 2003 | 37.8 C (100.0 F) |
| 2004 | 33.9 C (93.0 F) |
| 2005 | 37.8 C (100.0 F) |
| 2006 | 33.9 C (93.0 F) |
| 2007 | 33.9 C (93.0 F) |
| 2008 | 36.7 C (98.1 F) |
| 2009 | 35.6 C (96.1 F) |
| 2010 | 35.6 C (96.1 F) |
| 2011 | 37.8 C (100.0 F) |
| 2012 | 36.7 C (98.1 F) |
| 2013 | 35.0 C (95.0 F) |
Coldest night (TNn)
| Year | Coldest night (TNn) |
|---|---|
| 1967 | n/a |
| 1968 | n/a |
| 1969 | n/a |
| 1970 | -4.4 C (24.1 F) |
| 1971 | -3.3 C (26.1 F) |
| 1972 | -2.2 C (28.0 F) |
| 1973 | -3.3 C (26.1 F) |
| 1974 | -2.2 C (28.0 F) |
| 1975 | -5.0 C (23.0 F) |
| 1976 | -7.2 C (19.0 F) |
| 1977 | -1.1 C (30.0 F) |
| 1978 | -2.2 C (28.0 F) |
| 1979 | -3.3 C (26.1 F) |
| 1980 | -2.2 C (28.0 F) |
| 1981 | -4.4 C (24.1 F) |
| 1982 | -2.2 C (28.0 F) |
| 1983 | -5.0 C (23.0 F) |
| 1984 | -2.2 C (28.0 F) |
| 1985 | -6.1 C (21.0 F) |
| 1986 | -6.1 C (21.0 F) |
| 1987 | -4.4 C (24.1 F) |
| 1988 | -2.2 C (28.0 F) |
| 1989 | -5.0 C (23.0 F) |
| 1990 | -3.3 C (26.1 F) |
| 1991 | -1.1 C (30.0 F) |
| 1992 | -2.2 C (28.0 F) |
| 1993 | -1.1 C (30.0 F) |
| 1994 | -1.1 C (30.0 F) |
| 1995 | -1.1 C (30.0 F) |
| 1996 | -3.3 C (26.1 F) |
| 1997 | -9.4 C (15.1 F) |
| 1998 | -6.1 C (21.0 F) |
| 1999 | -4.4 C (24.1 F) |
| 2000 | -5.0 C (23.0 F) |
| 2001 | -4.4 C (24.1 F) |
| 2002 | -4.4 C (24.1 F) |
| 2003 | -8.3 C (17.1 F) |
| 2004 | -7.2 C (19.0 F) |
| 2005 | -2.2 C (28.0 F) |
| 2006 | -9.4 C (15.1 F) |
| 2007 | -4.4 C (24.1 F) |
| 2008 | -5.0 C (23.0 F) |
| 2009 | -4.4 C (24.1 F) |
| 2010 | -6.1 C (21.0 F) |
| 2011 | -7.2 C (19.0 F) |
| 2012 | -2.2 C (28.0 F) |
| 2013 | -3.3 C (26.1 F) |
Wettest day (Rx1day)
| Year | Wettest day (Rx1day) |
|---|---|
| 1967 | 42.9 mm (1.7 in) |
| 1968 | 39.9 mm (1.6 in) |
| 1969 | 19.8 mm (0.8 in) |
| 1970 | 59.9 mm (2.4 in) |
| 1971 | 39.9 mm (1.6 in) |
| 1972 | 39.9 mm (1.6 in) |
| 1973 | 52.8 mm (2.1 in) |
| 1974 | 31.8 mm (1.3 in) |
| 1975 | 59.9 mm (2.4 in) |
| 1976 | 36.8 mm (1.4 in) |
| 1977 | 34.5 mm (1.4 in) |
| 1978 | 82.3 mm (3.2 in) |
| 1979 | 30.0 mm (1.2 in) |
| 1980 | 38.1 mm (1.5 in) |
| 1981 | 33.5 mm (1.3 in) |
| 1982 | 28.4 mm (1.1 in) |
| 1983 | 57.9 mm (2.3 in) |
| 1984 | 49.8 mm (2.0 in) |
| 1985 | 53.3 mm (2.1 in) |
| 1986 | 32.3 mm (1.3 in) |
| 1987 | 31.0 mm (1.2 in) |
| 1988 | 64.8 mm (2.6 in) |
| 1989 | 50.3 mm (2.0 in) |
| 1990 | 64.8 mm (2.6 in) |
| 1991 | 36.8 mm (1.4 in) |
| 1992 | 47.5 mm (1.9 in) |
| 1993 | 47.0 mm (1.9 in) |
| 1994 | 31.0 mm (1.2 in) |
| 1995 | 31.0 mm (1.2 in) |
| 1996 | 45.5 mm (1.8 in) |
| 1997 | 28.4 mm (1.1 in) |
| 1998 | 52.3 mm (2.1 in) |
| 1999 | 35.8 mm (1.4 in) |
| 2000 | 82.3 mm (3.2 in) |
| 2001 | 55.4 mm (2.2 in) |
| 2002 | 62.5 mm (2.5 in) |
| 2003 | 48.3 mm (1.9 in) |
| 2004 | 85.3 mm (3.4 in) |
| 2005 | 53.3 mm (2.1 in) |
| 2006 | 42.4 mm (1.7 in) |
| 2007 | 50.8 mm (2.0 in) |
| 2008 | 78.5 mm (3.1 in) |
| 2009 | 41.9 mm (1.6 in) |
| 2010 | 66.8 mm (2.6 in) |
| 2011 | 78.0 mm (3.1 in) |
| 2012 | 40.4 mm (1.6 in) |
| 2013 | 52.8 mm (2.1 in) |
Wettest five days (Rx5day)
| Year | Wettest five days (Rx5day) |
|---|---|
| 1967 | 104.6 mm (4.1 in) |
| 1968 | 68.1 mm (2.7 in) |
| 1969 | 34.8 mm (1.4 in) |
| 1970 | 105.6 mm (4.2 in) |
| 1971 | 93.3 mm (3.7 in) |
| 1972 | 96.8 mm (3.8 in) |
| 1973 | 91.7 mm (3.6 in) |
| 1974 | 54.5 mm (2.1 in) |
| 1975 | 153.8 mm (6.1 in) |
| 1976 | 146.5 mm (5.8 in) |
| 1977 | 101.2 mm (4.0 in) |
| 1978 | 122.7 mm (4.8 in) |
| 1979 | 73.2 mm (2.9 in) |
| 1980 | 98.4 mm (3.9 in) |
| 1981 | 45.2 mm (1.8 in) |
| 1982 | 49.4 mm (1.9 in) |
| 1983 | 74.1 mm (2.9 in) |
| 1984 | 71.4 mm (2.8 in) |
| 1985 | 78.7 mm (3.1 in) |
| 1986 | 82.9 mm (3.3 in) |
| 1987 | 58.4 mm (2.3 in) |
| 1988 | 143.7 mm (5.7 in) |
| 1989 | 77.2 mm (3.0 in) |
| 1990 | 75.7 mm (3.0 in) |
| 1991 | 138.0 mm (5.4 in) |
| 1992 | 106.7 mm (4.2 in) |
| 1993 | 78.3 mm (3.1 in) |
| 1994 | 56.6 mm (2.2 in) |
| 1995 | 54.6 mm (2.1 in) |
| 1996 | 57.7 mm (2.3 in) |
| 1997 | 48.5 mm (1.9 in) |
| 1998 | 90.2 mm (3.6 in) |
| 1999 | 99.3 mm (3.9 in) |
| 2000 | 125.3 mm (4.9 in) |
| 2001 | 128.8 mm (5.1 in) |
| 2002 | 99.5 mm (3.9 in) |
| 2003 | 95.0 mm (3.7 in) |
| 2004 | 154.0 mm (6.1 in) |
| 2005 | 80.2 mm (3.2 in) |
| 2006 | 86.8 mm (3.4 in) |
| 2007 | 118.9 mm (4.7 in) |
| 2008 | 177.8 mm (7.0 in) |
| 2009 | 88.4 mm (3.5 in) |
| 2010 | 120.3 mm (4.7 in) |
| 2011 | 98.6 mm (3.9 in) |
| 2012 | 79.8 mm (3.1 in) |
| 2013 | 78.3 mm (3.1 in) |
Longest dry spell (CDD)
| Year | Longest dry spell (CDD) |
|---|---|
| 1967 | 63 days |
| 1968 | 47 days |
| 1969 | 170 days |
| 1970 | 98 days |
| 1971 | 67 days |
| 1972 | 49 days |
| 1973 | 75 days |
| 1974 | 147 days |
| 1975 | 110 days |
| 1976 | 90 days |
| 1977 | 70 days |
| 1978 | 97 days |
| 1979 | 109 days |
| 1980 | 51 days |
| 1981 | 38 days |
| 1982 | 107 days |
| 1983 | 126 days |
| 1984 | 89 days |
| 1985 | 83 days |
| 1986 | 79 days |
| 1987 | 93 days |
| 1988 | 62 days |
| 1989 | 125 days |
| 1990 | 70 days |
| 1991 | 115 days |
| 1992 | 41 days |
| 1993 | 101 days |
| 1994 | 87 days |
| 1995 | 48 days |
| 1996 | 113 days |
| 1997 | 50 days |
| 1998 | 158 days |
| 1999 | 137 days |
| 2000 | 140 days |
| 2001 | 75 days |
| 2002 | 48 days |
| 2003 | 113 days |
| 2004 | 48 days |
| 2005 | 72 days |
| 2006 | 86 days |
| 2007 | 108 days |
| 2008 | 110 days |
| 2009 | 127 days |
| 2010 | 101 days |
| 2011 | 171 days |
| 2012 | 98 days |
| 2013 | 130 days |
Each chart shows one value per year; the dot marks the record year. TXx is the hottest daily maximum, TNn the coldest daily minimum, Rx1day and Rx5day the largest one-day and five-day rain totals, and CDD the longest run of days with less than 1 mm of rain. A year with missing days can understate an extreme.
Frost Dates and Growing Season
34 years with a frostAcross 34 years with a frost, the median last spring frost at Palo Alto falls on 27 February and the median first autumn frost on 27 November, which leaves a median of 269 days between them.
Fitted over all years, the growing season changes by -5.4 days per decade at this station.
| Measure | Median, all years | Earliest period | Recent period (1975 to 2012) | Recent against earliest | Fitted trend |
|---|---|---|---|---|---|
| Last spring frost | 27 February | n/a | 27 February | n/a | +2.6 days per decade |
| First autumn frost | 27 November | n/a | 27 November | n/a | -2.7 days per decade |
| Growing days | 269 days | n/a | 267 days | n/a | -5.4 days per decade |
A frost day is a day with a daily minimum at or below 0 C (32 F). The last spring frost and the first autumn frost are the last and first such days of the cold season, and growing days are the days between them. A negative trend for the last spring frost means it comes earlier.
Rainfall Return Levels
45 years, 1968 to 2012A day with at least 45.6 mm (1.8 in) of rain is expected about once in 2 years. A day with at least 100.7 mm (4.0 in) of rain is expected about once in 100 years.
| Expected about once in | A day with at least | Note |
|---|---|---|
| 2 years | 45.6 mm (1.8 in) | |
| 5 years | 60.7 mm (2.4 in) | |
| 10 years | 70.5 mm (2.8 in) | |
| 25 years | 82.8 mm (3.3 in) | |
| 50 years | 91.8 mm (3.6 in) | Longer than the 45 years of record |
| 100 years | 100.7 mm (4.0 in) | Longer than the 45 years of record |
The levels come from a generalised extreme value (GEV) distribution fitted by L-moments to the wettest-day total of each year, 45 years of values from 1968 to 2012.
A return level is an estimate. It is least reliable for the long periods, 50 and 100 years, and for any period longer than the record behind the fit, where the fit has to reach past the largest day actually observed. It is not a forecast.
The largest wettest-day totals in the fit: 85.3 mm (3.4 in) in 2004; 82.3 mm (3.2 in) in 1978; 82.3 mm (3.2 in) in 2000.
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Source: NOAA National Centers for Environmental Information, Global Historical Climatology Network Daily (GHCN-Daily). Records are computed by World Extreme Weather Monitor and are not official NOAA products. (US Government open data (NOAA NCEI)) Data as of 2026-10-17 (17 October 2026). Records are computed by this site and are not official.
Data as of . Last revised (2025-12-31).