Record envelope, standing records and threshold days for Old Faithful (USC00486845), Wyoming, United States, with 123 years of record.
Key Facts for Old Faithful
Old Faithful (USC00486845) is a weather station in Wyoming, United States at 44.46 latitude and -110.83 longitude, 2,241 m (7,351 ft) above sea level.
The station reports from 1904 to 2026, 123 years of record.
1,464 records set at Old Faithful still stand.
Records are tracked for tmax, tmin, prcp, snow, snwd: an element needs 30 years of data to be eligible.
Old Faithful set a daily record low minimum temperature of -41.1 C (-42.0 F) on 21 February 2026.
About the Station
Location: Wyoming, United States, 44.46 latitude, -110.83 longitude.
Elevation: 2,241 m (7,351 ft).
Period of record: 1904 to 2026, 123 years.
Eligible elements: tmax, tmin, prcp, snow, snwd.
Daily Record Envelope and 2026
8 days at or beyond a record
Record highRecord low2026 daily maximum2026 daily minimum
The band shows the record high and record low for each calendar day at Old Faithful. The lines show the 2026 daily maximum and minimum. 8 days in 2026 matched or passed a record. Temperatures are in degrees Celsius.
Daily record high and record low at Old Faithful, with 2026 drawn through them
Month
Highest record high
Lowest record low
2026 highest maximum
2026 lowest minimum
Jan
12.8 C (55.0 F)
-42.8 C (-45.0 F)
7.8 C (46.0 F)
-38.9 C (-38.0 F)
Feb
16.7 C (62.1 F)
-45.0 C (-49.0 F)
12.2 C (54.0 F)
-41.1 C (-42.0 F)
Mar
17.2 C (63.0 F)
-40.6 C (-41.1 F)
5.6 C (42.1 F)
-15.0 C (5.0 F)
Apr
22.8 C (73.0 F)
-33.3 C (-27.9 F)
n/a
n/a
May
27.8 C (82.0 F)
-16.1 C (3.0 F)
n/a
n/a
Jun
31.7 C (89.1 F)
-8.9 C (16.0 F)
n/a
n/a
Jul
34.4 C (93.9 F)
-6.1 C (21.0 F)
n/a
n/a
Aug
36.7 C (98.1 F)
-10.0 C (14.0 F)
n/a
n/a
Sep
30.6 C (87.1 F)
-18.9 C (-2.0 F)
n/a
n/a
Oct
26.1 C (79.0 F)
-32.8 C (-27.0 F)
n/a
n/a
Nov
17.2 C (63.0 F)
-35.6 C (-32.1 F)
n/a
n/a
Dec
14.4 C (57.9 F)
-43.9 C (-47.0 F)
n/a
n/a
Which Years Hold Standing Records
1,464 standing records
Year with most
1,464 records at Old Faithful still stand. 1913 holds the most, with 50.
Standing records at Old Faithful by the year they were set
Year set
Standing records
1904
22
1905
34
1906
30
1907
18
1908
18
1909
28
1910
22
1911
20
1912
23
1913
50
1914
16
1915
21
1916
23
1934
8
1935
10
1936
37
1937
10
1938
10
1939
20
1940
20
1941
7
1942
6
1943
3
1944
4
1945
11
1947
6
1978
14
1979
26
1980
17
1981
14
1982
19
1983
15
1984
17
1985
31
1986
31
1987
31
1988
26
1989
11
1990
34
1991
23
1992
27
1993
27
1994
25
1995
19
1996
25
1997
11
1998
14
1999
32
2000
16
2001
16
2002
28
2003
22
2004
8
2005
14
2006
18
2007
12
2008
21
2009
11
2010
22
2011
13
2012
17
2013
27
2014
25
2015
21
2016
19
2017
24
2018
13
2019
25
2020
27
2021
18
2022
28
2023
11
2024
15
2025
17
2026
10
All-Time Record Progression
3 new records
3 all-time records were set at Old Faithful between 20 December 1990 and 5 June 2001. Each dot is a new record.
When Old Faithful set new all-time records
Date
Kind
Detail
1990-12-20
Record low maximum temperature
Record low maximum temperature -22.8 C (-9.0 F)
1990-12-22
Record low maximum temperature
Record low maximum temperature -24.4 C (-11.9 F)
2001-06-05
Record daily precipitation
Record daily precipitation 76.2 mm (3.0 in)
Wettest Day of Each Month
Jun: 76.2 mm (3.0 in)
The wettest day on record for each calendar month at Old Faithful. The most was 76.2 mm (3.0 in) on 5 June 2001.
Record daily precipitation for each month at Old Faithful
Month
Record daily precipitation (mm)
Date
Jan
66.0 mm (2.6 in)
15 January 1913
Feb
39.1 mm (1.5 in)
26 February 2019
Mar
50.8 mm (2.0 in)
13 March 1906
Apr
39.4 mm (1.6 in)
27 April 2017
May
42.4 mm (1.7 in)
26 May 1980
Jun
76.2 mm (3.0 in)
5 June 2001
Jul
38.1 mm (1.5 in)
24 July 1913
Aug
48.3 mm (1.9 in)
1 August 1912
Sep
41.9 mm (1.6 in)
30 September 2013
Oct
68.6 mm (2.7 in)
15 October 1908
Nov
39.6 mm (1.6 in)
19 November 1996
Dec
34.8 mm (1.4 in)
14 December 2003
Period of Record Coverage
1904 to 2026
Complete yearUnder 90 percent of days
76 years of record at Old Faithful, 1904 to 2026. 37 years have data for under 90 percent of days and are left out of rankings: 1904, 1905, 1906, 1908, 1909, 1910, 1912, 1913 and others.
Cooler than the station meanWarmer than the station mean
One stripe for each of 34 complete years at Old Faithful, 1907 to 2022. Blue stripes are years cooler than the station's own mean of 1.3 C (34.4 F); red stripes are warmer. The coolest year was 1979, at 0.1 C (32.1 F), and the warmest was 2015, at 2.6 C (36.6 F). The strongest colour marks a difference of 1.3 C (2.3 F).
Annual mean temperature at Old Faithful as warming stripes, 1907 to 2022
Year
Annual mean temperature
Difference from the station mean
1907
1.8 C
+0.48 C
1915
1.7 C
+0.35 C
1979
0.1 C
-1.25 C
1980
0.7 C
-0.64 C
1986
1.2 C
-0.17 C
1987
1.9 C
+0.58 C
1988
2.0 C
+0.65 C
1989
1.5 C
+0.13 C
1990
0.9 C
-0.40 C
1991
1.1 C
-0.20 C
1992
1.9 C
+0.57 C
1993
0.2 C
-1.10 C
1994
1.8 C
+0.42 C
1995
1.7 C
+0.33 C
1997
0.6 C
-0.70 C
1998
1.8 C
+0.42 C
1999
1.2 C
-0.14 C
2000
1.2 C
-0.09 C
2002
0.5 C
-0.79 C
2003
1.7 C
+0.41 C
2004
1.6 C
+0.30 C
2006
1.3 C
-0.04 C
2007
2.0 C
+0.64 C
2008
0.2 C
-1.12 C
2011
0.3 C
-1.03 C
2012
2.3 C
+0.94 C
2013
1.0 C
-0.34 C
2014
1.5 C
+0.16 C
2015
2.6 C
+1.24 C
2016
2.3 C
+1.00 C
2019
0.7 C
-0.68 C
2020
1.2 C
-0.10 C
2021
2.1 C
+0.72 C
2022
0.8 C
-0.49 C
The fitted trend in annual mean temperature here over 1907 to 2022 is -0.01 C (-0.11 to 0.08) per decade. The interval includes zero, so the trend is not clearly different from zero. In Fahrenheit: -0.02 F (-0.19 to 0.15) per decade. The slope is a straight line fitted to 34 complete years; the brackets give its 95 percent interval.
Fitted temperature trends per decade at Old Faithful
Measure
Per decade (C)
Per decade (F)
Period
Complete years
Reading
Annual mean temperature
-0.01 C (-0.11 to 0.08) per decade
-0.02 F (-0.19 to 0.15) per decade
1907 to 2022
34
Not clearly different from zero
Mean daily maximum
-0.02 C (-0.14 to 0.10) per decade
-0.03 F (-0.25 to 0.18) per decade
1907 to 2022
34
Not clearly different from zero
Mean daily minimum
-0.01 C (-0.13 to 0.12) per decade
-0.01 F (-0.24 to 0.21) per decade
1907 to 2022
34
Not clearly different from zero
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
1904 to 2026
Yearly extremes at Old Faithful: the record and the median year
Measure
Record
Year of the record
Median year
Years with a value
Hottest day (TXx)
36.7 C (98.1 F)
1984
30.0 C (86.0 F)
76
Coldest night (TNn)
-45.0 C (-49.0 F)
1981
-36.4 C (-33.5 F)
76
Wettest day (Rx1day)
76.2 mm (3.0 in)
2001
29.7 mm (1.2 in)
76
Wettest five days (Rx5day)
119.0 mm (4.7 in)
1997
52.1 mm (2.0 in)
76
Longest dry spell (CDD)
81 days
1911
22 days
76
Hottest day (TXx)
The hottest day of the year at Old Faithful, 1904 to 2026. The record is 36.7 C (98.1 F) in 1984, marked on the chart; the median year is 30.0 C (86.0 F).
Hottest day (TXx) at Old Faithful by year
Year
Hottest day (TXx)
1904
28.9 C (84.0 F)
1905
36.1 C (97.0 F)
1906
29.4 C (84.9 F)
1907
32.2 C (90.0 F)
1908
29.4 C (84.9 F)
1909
20.6 C (69.1 F)
1910
31.1 C (88.0 F)
1911
27.8 C (82.0 F)
1912
31.7 C (89.1 F)
1913
28.3 C (82.9 F)
1914
27.2 C (81.0 F)
1915
28.9 C (84.0 F)
1916
31.7 C (89.1 F)
1934
26.1 C (79.0 F)
1935
32.2 C (90.0 F)
1936
33.3 C (91.9 F)
1937
30.6 C (87.1 F)
1938
28.3 C (82.9 F)
1939
31.7 C (89.1 F)
1940
31.7 C (89.1 F)
1941
30.0 C (86.0 F)
1942
31.7 C (89.1 F)
1943
30.0 C (86.0 F)
1944
30.0 C (86.0 F)
1945
28.9 C (84.0 F)
1946
29.4 C (84.9 F)
1947
29.4 C (84.9 F)
1978
25.6 C (78.1 F)
1979
29.4 C (84.9 F)
1980
28.3 C (82.9 F)
1981
28.3 C (82.9 F)
1982
28.9 C (84.0 F)
1983
34.4 C (93.9 F)
1984
36.7 C (98.1 F)
1985
30.0 C (86.0 F)
1986
30.0 C (86.0 F)
1987
31.1 C (88.0 F)
1988
31.7 C (89.1 F)
1989
29.4 C (84.9 F)
1990
30.0 C (86.0 F)
1991
29.4 C (84.9 F)
1992
28.9 C (84.0 F)
1993
28.3 C (82.9 F)
1994
31.7 C (89.1 F)
1995
29.4 C (84.9 F)
1996
28.9 C (84.0 F)
1997
30.0 C (86.0 F)
1998
30.6 C (87.1 F)
1999
31.1 C (88.0 F)
2000
31.1 C (88.0 F)
2001
29.4 C (84.9 F)
2002
32.8 C (91.0 F)
2003
31.7 C (89.1 F)
2004
28.9 C (84.0 F)
2005
30.6 C (87.1 F)
2006
30.6 C (87.1 F)
2007
31.7 C (89.1 F)
2008
31.1 C (88.0 F)
2009
28.9 C (84.0 F)
2010
27.8 C (82.0 F)
2011
28.9 C (84.0 F)
2012
29.4 C (84.9 F)
2013
31.1 C (88.0 F)
2014
28.3 C (82.9 F)
2015
31.1 C (88.0 F)
2016
30.0 C (86.0 F)
2017
30.6 C (87.1 F)
2018
32.2 C (90.0 F)
2019
29.4 C (84.9 F)
2020
31.1 C (88.0 F)
2021
32.2 C (90.0 F)
2022
30.6 C (87.1 F)
2023
31.1 C (88.0 F)
2024
31.7 C (89.1 F)
2025
15.6 C (60.1 F)
2026
12.2 C (54.0 F)
Coldest night (TNn)
The coldest night of the year at Old Faithful, 1904 to 2026. The record is -45.0 C (-49.0 F) in 1981, marked on the chart; the median year is -36.4 C (-33.5 F).
Coldest night (TNn) at Old Faithful by year
Year
Coldest night (TNn)
1904
-35.6 C (-32.1 F)
1905
-42.8 C (-45.0 F)
1906
-40.6 C (-41.1 F)
1907
-33.3 C (-27.9 F)
1908
-40.0 C (-40.0 F)
1909
-32.2 C (-26.0 F)
1910
-36.7 C (-34.1 F)
1911
-40.0 C (-40.0 F)
1912
-33.3 C (-27.9 F)
1913
-42.8 C (-45.0 F)
1914
-40.6 C (-41.1 F)
1915
-38.9 C (-38.0 F)
1916
-36.1 C (-33.0 F)
1934
-25.0 C (-13.0 F)
1935
-31.7 C (-25.1 F)
1936
-40.6 C (-41.1 F)
1937
-32.8 C (-27.0 F)
1938
-32.8 C (-27.0 F)
1939
-31.1 C (-24.0 F)
1940
-35.0 C (-31.0 F)
1941
-15.0 C (5.0 F)
1942
-11.7 C (10.9 F)
1943
-7.8 C (18.0 F)
1944
-7.2 C (19.0 F)
1945
-10.6 C (12.9 F)
1946
-3.3 C (26.1 F)
1947
-5.0 C (23.0 F)
1978
-43.9 C (-47.0 F)
1979
-42.2 C (-44.0 F)
1980
-41.7 C (-43.1 F)
1981
-45.0 C (-49.0 F)
1982
-41.7 C (-43.1 F)
1983
-29.4 C (-20.9 F)
1984
-35.6 C (-32.1 F)
1985
-41.7 C (-43.1 F)
1986
-35.6 C (-32.1 F)
1987
-34.4 C (-29.9 F)
1988
-37.8 C (-36.0 F)
1989
-37.8 C (-36.0 F)
1990
-43.3 C (-45.9 F)
1991
-36.7 C (-34.1 F)
1992
-37.8 C (-36.0 F)
1993
-35.6 C (-32.1 F)
1994
-32.8 C (-27.0 F)
1995
-35.0 C (-31.0 F)
1996
-42.2 C (-44.0 F)
1997
-35.0 C (-31.0 F)
1998
-42.8 C (-45.0 F)
1999
-33.3 C (-27.9 F)
2000
-30.6 C (-23.1 F)
2001
-37.2 C (-35.0 F)
2002
-36.7 C (-34.1 F)
2003
-41.1 C (-42.0 F)
2004
-35.0 C (-31.0 F)
2005
-36.7 C (-34.1 F)
2006
-37.2 C (-35.0 F)
2007
-41.1 C (-42.0 F)
2008
-37.2 C (-35.0 F)
2009
-33.9 C (-29.0 F)
2010
-36.7 C (-34.1 F)
2011
-40.0 C (-40.0 F)
2012
-33.3 C (-27.9 F)
2013
-38.3 C (-36.9 F)
2014
-36.1 C (-33.0 F)
2015
-34.4 C (-29.9 F)
2016
-41.1 C (-42.0 F)
2017
-35.6 C (-32.1 F)
2018
-35.6 C (-32.1 F)
2019
-40.0 C (-40.0 F)
2020
-34.4 C (-29.9 F)
2021
-31.1 C (-24.0 F)
2022
-37.8 C (-36.0 F)
2023
-35.6 C (-32.1 F)
2024
-39.4 C (-38.9 F)
2025
-42.8 C (-45.0 F)
2026
-41.1 C (-42.0 F)
Wettest day (Rx1day)
The wettest day of the year at Old Faithful, 1904 to 2026. The record is 76.2 mm (3.0 in) in 2001, marked on the chart; the median year is 29.7 mm (1.2 in).
Wettest day (Rx1day) at Old Faithful by year
Year
Wettest day (Rx1day)
1904
17.8 mm (0.7 in)
1905
29.5 mm (1.2 in)
1906
50.8 mm (2.0 in)
1907
35.6 mm (1.4 in)
1908
68.6 mm (2.7 in)
1909
30.5 mm (1.2 in)
1910
58.4 mm (2.3 in)
1911
30.5 mm (1.2 in)
1912
48.3 mm (1.9 in)
1913
66.0 mm (2.6 in)
1914
17.8 mm (0.7 in)
1915
30.5 mm (1.2 in)
1916
24.6 mm (1.0 in)
1934
21.6 mm (0.9 in)
1935
18.3 mm (0.7 in)
1936
34.0 mm (1.3 in)
1937
33.0 mm (1.3 in)
1938
19.3 mm (0.8 in)
1939
16.3 mm (0.6 in)
1940
39.4 mm (1.6 in)
1941
33.5 mm (1.3 in)
1942
10.2 mm (0.4 in)
1943
13.5 mm (0.5 in)
1944
37.3 mm (1.5 in)
1945
16.5 mm (0.6 in)
1946
4.3 mm (0.17 in)
1947
17.8 mm (0.7 in)
1978
26.4 mm (1.0 in)
1979
22.4 mm (0.9 in)
1980
42.4 mm (1.7 in)
1981
20.6 mm (0.8 in)
1982
32.3 mm (1.3 in)
1983
27.9 mm (1.1 in)
1984
23.4 mm (0.9 in)
1985
30.5 mm (1.2 in)
1986
26.2 mm (1.0 in)
1987
22.9 mm (0.9 in)
1988
20.1 mm (0.8 in)
1989
22.4 mm (0.9 in)
1990
22.9 mm (0.9 in)
1991
25.9 mm (1.0 in)
1992
22.9 mm (0.9 in)
1993
22.4 mm (0.9 in)
1994
33.0 mm (1.3 in)
1995
35.6 mm (1.4 in)
1996
39.6 mm (1.6 in)
1997
52.3 mm (2.1 in)
1998
34.8 mm (1.4 in)
1999
29.2 mm (1.1 in)
2000
25.7 mm (1.0 in)
2001
76.2 mm (3.0 in)
2002
21.6 mm (0.9 in)
2003
34.8 mm (1.4 in)
2004
46.5 mm (1.8 in)
2005
35.6 mm (1.4 in)
2006
24.4 mm (1.0 in)
2007
36.8 mm (1.4 in)
2008
29.7 mm (1.2 in)
2009
27.2 mm (1.1 in)
2010
32.5 mm (1.3 in)
2011
23.4 mm (0.9 in)
2012
23.4 mm (0.9 in)
2013
41.9 mm (1.6 in)
2014
34.8 mm (1.4 in)
2015
21.6 mm (0.9 in)
2016
37.8 mm (1.5 in)
2017
39.4 mm (1.6 in)
2018
29.7 mm (1.2 in)
2019
39.1 mm (1.5 in)
2020
38.1 mm (1.5 in)
2021
20.3 mm (0.8 in)
2022
55.4 mm (2.2 in)
2023
30.7 mm (1.2 in)
2024
22.9 mm (0.9 in)
2025
32.8 mm (1.3 in)
2026
11.9 mm (0.5 in)
Wettest five days (Rx5day)
The wettest five days of the year at Old Faithful, 1904 to 2026. The record is 119.0 mm (4.7 in) in 1997, marked on the chart; the median year is 52.1 mm (2.0 in).
Wettest five days (Rx5day) at Old Faithful by year
Year
Wettest five days (Rx5day)
1904
31.5 mm (1.2 in)
1905
37.0 mm (1.5 in)
1906
64.2 mm (2.5 in)
1907
59.5 mm (2.3 in)
1908
107.2 mm (4.2 in)
1909
55.9 mm (2.2 in)
1910
58.4 mm (2.3 in)
1911
52.2 mm (2.1 in)
1912
73.7 mm (2.9 in)
1913
69.1 mm (2.7 in)
1914
34.3 mm (1.4 in)
1915
58.4 mm (2.3 in)
1916
47.0 mm (1.9 in)
1934
34.7 mm (1.4 in)
1935
25.7 mm (1.0 in)
1936
53.9 mm (2.1 in)
1937
54.8 mm (2.2 in)
1938
42.2 mm (1.7 in)
1939
32.8 mm (1.3 in)
1940
72.1 mm (2.8 in)
1941
53.6 mm (2.1 in)
1942
18.1 mm (0.7 in)
1943
24.0 mm (0.9 in)
1944
37.3 mm (1.5 in)
1945
44.5 mm (1.8 in)
1946
9.9 mm (0.39 in)
1947
35.8 mm (1.4 in)
1978
47.0 mm (1.9 in)
1979
39.6 mm (1.6 in)
1980
66.2 mm (2.6 in)
1981
39.7 mm (1.6 in)
1982
71.9 mm (2.8 in)
1983
32.3 mm (1.3 in)
1984
30.0 mm (1.2 in)
1985
71.8 mm (2.8 in)
1986
66.6 mm (2.6 in)
1987
43.7 mm (1.7 in)
1988
46.1 mm (1.8 in)
1989
37.1 mm (1.5 in)
1990
38.2 mm (1.5 in)
1991
69.9 mm (2.8 in)
1992
49.3 mm (1.9 in)
1993
51.8 mm (2.0 in)
1994
56.3 mm (2.2 in)
1995
70.8 mm (2.8 in)
1996
97.2 mm (3.8 in)
1997
119.0 mm (4.7 in)
1998
64.3 mm (2.5 in)
1999
69.1 mm (2.7 in)
2000
44.2 mm (1.7 in)
2001
76.5 mm (3.0 in)
2002
44.7 mm (1.8 in)
2003
43.2 mm (1.7 in)
2004
88.7 mm (3.5 in)
2005
68.3 mm (2.7 in)
2006
50.1 mm (2.0 in)
2007
48.5 mm (1.9 in)
2008
47.2 mm (1.9 in)
2009
40.3 mm (1.6 in)
2010
67.4 mm (2.7 in)
2011
50.3 mm (2.0 in)
2012
53.3 mm (2.1 in)
2013
66.1 mm (2.6 in)
2014
79.3 mm (3.1 in)
2015
59.2 mm (2.3 in)
2016
74.4 mm (2.9 in)
2017
82.8 mm (3.3 in)
2018
53.6 mm (2.1 in)
2019
80.9 mm (3.2 in)
2020
46.0 mm (1.8 in)
2021
69.3 mm (2.7 in)
2022
76.2 mm (3.0 in)
2023
44.1 mm (1.7 in)
2024
51.9 mm (2.0 in)
2025
33.3 mm (1.3 in)
2026
14.4 mm (0.6 in)
Longest dry spell (CDD)
The longest dry spell of the year at Old Faithful, 1904 to 2026. The record is 81 days in 1911, marked on the chart; the median year is 22 days.
Longest dry spell (CDD) at Old Faithful by year
Year
Longest dry spell (CDD)
1904
29 days
1905
21 days
1906
19 days
1907
48 days
1908
21 days
1909
30 days
1910
32 days
1911
81 days
1912
32 days
1913
28 days
1914
42 days
1915
22 days
1916
18 days
1934
14 days
1935
16 days
1936
29 days
1937
26 days
1938
11 days
1939
37 days
1940
21 days
1941
17 days
1942
24 days
1943
23 days
1944
35 days
1945
13 days
1946
21 days
1947
11 days
1978
29 days
1979
24 days
1980
23 days
1981
33 days
1982
30 days
1983
26 days
1984
28 days
1985
17 days
1986
27 days
1987
39 days
1988
28 days
1989
23 days
1990
15 days
1991
21 days
1992
15 days
1993
20 days
1994
29 days
1995
16 days
1996
17 days
1997
16 days
1998
22 days
1999
37 days
2000
17 days
2001
21 days
2002
25 days
2003
33 days
2004
20 days
2005
23 days
2006
22 days
2007
17 days
2008
18 days
2009
13 days
2010
19 days
2011
19 days
2012
32 days
2013
17 days
2014
16 days
2015
14 days
2016
19 days
2017
19 days
2018
17 days
2019
27 days
2020
22 days
2021
28 days
2022
19 days
2023
27 days
2024
9 days
2025
20 days
2026
8 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 frost
Across 34 years with a frost, the median last spring frost at Old Faithful falls on 27 June and the median first autumn frost on 8 July, which leaves a median of 12 days between them.
Fitted over all years, the growing season changes by +2.7 days per decade at this station.
Frost dates and growing season at Old Faithful
Measure
Median, all years
Earliest period
Recent period (1986 to 2022)
Recent against earliest
Fitted trend
Last spring frost
27 June
n/a
27 June
n/a
-0.4 days per decade
First autumn frost
8 July
n/a
9 July
n/a
+2.3 days per decade
Growing days
12 days
n/a
16 days
n/a
+2.7 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
37 years, 1907 to 2022
A day with at least 29.9 mm (1.2 in) of rain is expected about once in 2 years. A day with at least 61.4 mm (2.4 in) of rain is expected about once in 100 years.
Rainfall return levels at Old Faithful: the daily rain expected about once in a given number of years
Expected about once in
A day with at least
Note
2 years
29.9 mm (1.2 in)
5 years
38.2 mm (1.5 in)
10 years
43.8 mm (1.7 in)
25 years
50.8 mm (2.0 in)
50 years
56.1 mm (2.2 in)
Longer than the 37 years of record
100 years
61.4 mm (2.4 in)
Longer than the 37 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, 37 years of values from 1907 to 2022.
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: 55.4 mm (2.2 in) in 2022; 52.3 mm (2.1 in) in 1997; 46.5 mm (1.8 in) in 2004.
Download the Data
Data for Old Faithful standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Old Faithful threshold days by year: CSV or JSON. Field meanings are on the data page.
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 2026-10-15 (15 October 2026). Records are computed by this site and are not official.