Record envelope, standing records and threshold days for Portal 4 SW (USC00026716), Arizona, United States, with 57 years of record.
Key Facts for Portal 4 SW
Portal 4 SW (USC00026716) is a weather station in Arizona, United States at 31.88 latitude and -109.21 longitude, 1,643 m (5,390 ft) above sea level.
The station reports from 1965 to 2021, 57 years of record.
1,464 records set at Portal 4 SW still stand.
Records are tracked for tmax, tmin, prcp, snow, snwd: an element needs 30 years of data to be eligible.
Portal 4 SW set a daily record precipitation of 33.5 mm (1.3 in) on 1 September 2021.
About the Station
Location: Arizona, United States, 31.88 latitude, -109.21 longitude.
Elevation: 1,643 m (5,390 ft).
Period of record: 1965 to 2021, 57 years.
Eligible elements: tmax, tmin, prcp, snow, snwd.
Daily Record Envelope and 2026
0 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 Portal 4 SW. The lines show the 2026 daily maximum and minimum. 0 days in 2026 matched or passed a record. Temperatures are in degrees Celsius.
Daily record high and record low at Portal 4 SW, with 2026 drawn through them
Month
Highest record high
Lowest record low
2026 highest maximum
2026 lowest minimum
Jan
24.4 C (75.9 F)
-18.3 C (-0.9 F)
n/a
n/a
Feb
27.8 C (82.0 F)
-16.7 C (1.9 F)
n/a
n/a
Mar
28.9 C (84.0 F)
-13.3 C (8.1 F)
n/a
n/a
Apr
31.1 C (88.0 F)
-8.9 C (16.0 F)
n/a
n/a
May
35.6 C (96.1 F)
-6.7 C (19.9 F)
n/a
n/a
Jun
38.3 C (100.9 F)
-0.6 C (30.9 F)
n/a
n/a
Jul
38.3 C (100.9 F)
5.6 C (42.1 F)
n/a
n/a
Aug
35.0 C (95.0 F)
5.0 C (41.0 F)
n/a
n/a
Sep
33.9 C (93.0 F)
-1.7 C (28.9 F)
n/a
n/a
Oct
31.7 C (89.1 F)
-8.9 C (16.0 F)
n/a
n/a
Nov
27.8 C (82.0 F)
-13.3 C (8.1 F)
n/a
n/a
Dec
23.9 C (75.0 F)
-20.6 C (-5.1 F)
n/a
n/a
Which Years Hold Standing Records
1,464 standing records
Year with most
1,464 records at Portal 4 SW still stand. 1979 holds the most, with 47.
Standing records at Portal 4 SW by the year they were set
Year set
Standing records
1965
32
1966
29
1967
25
1968
35
1969
36
1970
39
1971
43
1972
29
1973
43
1974
35
1975
35
1976
24
1977
24
1978
27
1979
47
1980
40
1981
14
1982
28
1983
37
1984
18
1985
25
1986
21
1987
36
1988
25
1989
22
1990
30
1991
30
1992
37
1993
20
1994
35
1995
27
1996
26
1997
19
1998
23
1999
17
2000
33
2001
11
2002
15
2003
18
2004
26
2005
19
2006
16
2007
18
2008
18
2009
20
2010
14
2011
30
2012
20
2013
20
2014
19
2015
19
2016
34
2017
47
2018
29
2019
4
2020
1
All-Time Record Progression
3 new records
3 all-time records were set at Portal 4 SW between 30 June 1996 and 3 February 2011. Each dot is a new record.
When Portal 4 SW set new all-time records
Date
Kind
Detail
1996-06-30
Record daily precipitation
Record daily precipitation 106.7 mm (4.2 in)
2005-08-26
Record high minimum temperature
Record high minimum temperature 23.3 C (73.9 F)
2011-02-03
Record low maximum temperature
Record low maximum temperature -7.8 C (18.0 F)
Wettest Day of Each Month
Jun: 106.7 mm (4.2 in)
The wettest day on record for each calendar month at Portal 4 SW. The most was 106.7 mm (4.2 in) on 30 June 1996.
Record daily precipitation for each month at Portal 4 SW
Month
Record daily precipitation (mm)
Date
Jan
49.3 mm (1.9 in)
22 January 2010
Feb
39.9 mm (1.6 in)
28 February 1997
Mar
41.7 mm (1.6 in)
7 March 2020
Apr
74.4 mm (2.9 in)
27 April 1987
May
40.6 mm (1.6 in)
5 May 1992
Jun
106.7 mm (4.2 in)
30 June 1996
Jul
103.1 mm (4.1 in)
15 July 1986
Aug
77.5 mm (3.1 in)
27 August 2010
Sep
64.8 mm (2.6 in)
5 September 1975
Oct
63.5 mm (2.5 in)
11 October 2000
Nov
71.1 mm (2.8 in)
12 November 1994
Dec
70.9 mm (2.8 in)
15 December 1967
Period of Record Coverage
1965 to 2021
Complete yearUnder 90 percent of days
57 years of record at Portal 4 SW, 1965 to 2021. 8 years have data for under 90 percent of days and are left out of rankings: 1965, 2006, 2008, 2009, 2018, 2019, 2020, 2021.
Cooler than the station meanWarmer than the station mean
One stripe for each of 43 complete years at Portal 4 SW, 1966 to 2017. Blue stripes are years cooler than the station's own mean of 12.6 C (54.6 F); red stripes are warmer. The coolest year was 1991, at 11.1 C (52.0 F), and the warmest was 2017, at 15.0 C (58.9 F). The strongest colour marks a difference of 2.4 C (4.3 F).
Annual mean temperature at Portal 4 SW as warming stripes, 1966 to 2017
Year
Annual mean temperature
Difference from the station mean
1966
11.8 C
-0.75 C
1967
12.4 C
-0.18 C
1968
12.0 C
-0.55 C
1969
12.7 C
+0.09 C
1970
12.3 C
-0.27 C
1971
12.3 C
-0.22 C
1972
12.5 C
-0.02 C
1973
11.4 C
-1.15 C
1974
12.2 C
-0.40 C
1975
11.7 C
-0.87 C
1976
11.5 C
-1.02 C
1977
12.5 C
-0.06 C
1978
12.6 C
-0.01 C
1979
12.1 C
-0.50 C
1980
12.7 C
+0.10 C
1981
12.9 C
+0.35 C
1982
12.7 C
+0.12 C
1983
12.5 C
-0.08 C
1984
12.6 C
+0.03 C
1985
12.6 C
-0.01 C
1986
12.6 C
+0.04 C
1987
11.6 C
-0.95 C
1988
12.0 C
-0.54 C
1989
12.1 C
-0.44 C
1990
11.8 C
-0.75 C
1991
11.1 C
-1.47 C
1992
11.3 C
-1.30 C
1993
11.8 C
-0.78 C
1994
12.9 C
+0.36 C
1995
12.9 C
+0.38 C
1996
13.2 C
+0.62 C
1998
12.4 C
-0.16 C
1999
12.7 C
+0.10 C
2002
12.9 C
+0.29 C
2003
13.2 C
+0.60 C
2005
12.8 C
+0.26 C
2010
13.0 C
+0.46 C
2011
13.7 C
+1.10 C
2013
13.2 C
+0.61 C
2014
14.1 C
+1.51 C
2015
14.0 C
+1.47 C
2016
14.2 C
+1.63 C
2017
15.0 C
+2.39 C
The annual mean temperature here has risen by 0.4 C (0.2 to 0.5) per decade over 1966 to 2017. In Fahrenheit: 0.6 F (0.4 to 0.9) per decade. The slope is a straight line fitted to 43 complete years; the brackets give its 95 percent interval.
Fitted temperature trends per decade at Portal 4 SW
Measure
Per decade (C)
Per decade (F)
Period
Complete years
Reading
Annual mean temperature
0.4 C (0.2 to 0.5) per decade
0.6 F (0.4 to 0.9) per decade
1966 to 2017
43
Rise
Mean daily maximum
0.3 C (0.2 to 0.5) per decade
0.6 F (0.3 to 0.8) per decade
1966 to 2017
43
Rise
Mean daily minimum
0.4 C (0.3 to 0.5) per decade
0.7 F (0.5 to 0.9) per decade
1966 to 2017
43
Rise
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
1965 to 2021
Yearly extremes at Portal 4 SW: the record and the median year
Measure
Record
Year of the record
Median year
Years with a value
Hottest day (TXx)
38.3 C (100.9 F)
1990
36.1 C (97.0 F)
57
Coldest night (TNn)
-20.6 C (-5.1 F)
1978
-13.3 C (8.1 F)
57
Wettest day (Rx1day)
106.7 mm (4.2 in)
1996
42.9 mm (1.7 in)
57
Wettest five days (Rx5day)
165.1 mm (6.5 in)
1967
77.0 mm (3.0 in)
56
Longest dry spell (CDD)
148 days
1972
52 days
56
Hottest day (TXx)
The hottest day of the year at Portal 4 SW, 1965 to 2021. The record is 38.3 C (100.9 F) in 1990, marked on the chart; the median year is 36.1 C (97.0 F).
Hottest day (TXx) at Portal 4 SW by year
Year
Hottest day (TXx)
1965
35.6 C (96.1 F)
1966
35.6 C (96.1 F)
1967
34.4 C (93.9 F)
1968
36.1 C (97.0 F)
1969
37.2 C (99.0 F)
1970
36.7 C (98.1 F)
1971
37.2 C (99.0 F)
1972
35.6 C (96.1 F)
1973
36.7 C (98.1 F)
1974
37.2 C (99.0 F)
1975
34.4 C (93.9 F)
1976
33.9 C (93.0 F)
1977
35.0 C (95.0 F)
1978
36.1 C (97.0 F)
1979
36.7 C (98.1 F)
1980
37.8 C (100.0 F)
1981
36.7 C (98.1 F)
1982
35.0 C (95.0 F)
1983
35.6 C (96.1 F)
1984
34.4 C (93.9 F)
1985
36.1 C (97.0 F)
1986
34.4 C (93.9 F)
1987
34.4 C (93.9 F)
1988
34.4 C (93.9 F)
1989
37.2 C (99.0 F)
1990
38.3 C (100.9 F)
1991
34.4 C (93.9 F)
1992
35.0 C (95.0 F)
1993
35.0 C (95.0 F)
1994
38.3 C (100.9 F)
1995
36.1 C (97.0 F)
1996
35.6 C (96.1 F)
1997
36.1 C (97.0 F)
1998
36.1 C (97.0 F)
1999
35.6 C (96.1 F)
2000
35.6 C (96.1 F)
2001
33.9 C (93.0 F)
2002
36.7 C (98.1 F)
2003
36.7 C (98.1 F)
2004
33.9 C (93.0 F)
2005
36.7 C (98.1 F)
2006
36.1 C (97.0 F)
2007
36.7 C (98.1 F)
2008
35.6 C (96.1 F)
2009
33.9 C (93.0 F)
2010
36.1 C (97.0 F)
2011
37.8 C (100.0 F)
2012
36.1 C (97.0 F)
2013
35.6 C (96.1 F)
2014
36.1 C (97.0 F)
2015
35.6 C (96.1 F)
2016
37.2 C (99.0 F)
2017
37.2 C (99.0 F)
2018
36.1 C (97.0 F)
2019
27.2 C (81.0 F)
2020
26.1 C (79.0 F)
2021
27.8 C (82.0 F)
Coldest night (TNn)
The coldest night of the year at Portal 4 SW, 1965 to 2021. The record is -20.6 C (-5.1 F) in 1978, marked on the chart; the median year is -13.3 C (8.1 F).
Coldest night (TNn) at Portal 4 SW by year
Year
Coldest night (TNn)
1965
-13.3 C (8.1 F)
1966
-14.4 C (6.1 F)
1967
-15.6 C (3.9 F)
1968
-14.4 C (6.1 F)
1969
-13.9 C (7.0 F)
1970
-15.6 C (3.9 F)
1971
-18.3 C (-0.9 F)
1972
-15.0 C (5.0 F)
1973
-12.8 C (9.0 F)
1974
-15.0 C (5.0 F)
1975
-15.6 C (3.9 F)
1976
-14.4 C (6.1 F)
1977
-12.2 C (10.0 F)
1978
-20.6 C (-5.1 F)
1979
-16.7 C (1.9 F)
1980
-16.7 C (1.9 F)
1981
-11.1 C (12.0 F)
1982
-13.9 C (7.0 F)
1983
-16.1 C (3.0 F)
1984
-10.6 C (12.9 F)
1985
-14.4 C (6.1 F)
1986
-11.1 C (12.0 F)
1987
-19.4 C (-2.9 F)
1988
-14.4 C (6.1 F)
1989
-14.4 C (6.1 F)
1990
-15.6 C (3.9 F)
1991
-13.3 C (8.1 F)
1992
-13.9 C (7.0 F)
1993
-12.2 C (10.0 F)
1994
-13.3 C (8.1 F)
1995
-10.6 C (12.9 F)
1996
-14.4 C (6.1 F)
1997
-18.3 C (-0.9 F)
1998
-11.7 C (10.9 F)
1999
-13.3 C (8.1 F)
2000
-11.1 C (12.0 F)
2001
-12.8 C (9.0 F)
2002
-13.3 C (8.1 F)
2003
-15.6 C (3.9 F)
2004
-14.4 C (6.1 F)
2005
-12.8 C (9.0 F)
2006
-13.3 C (8.1 F)
2007
-14.4 C (6.1 F)
2008
-10.6 C (12.9 F)
2009
-10.6 C (12.9 F)
2010
-12.2 C (10.0 F)
2011
-16.7 C (1.9 F)
2012
-9.4 C (15.1 F)
2013
-16.7 C (1.9 F)
2014
-10.0 C (14.0 F)
2015
-11.7 C (10.9 F)
2016
-11.7 C (10.9 F)
2017
-10.6 C (12.9 F)
2018
-10.0 C (14.0 F)
2019
-11.7 C (10.9 F)
2020
-8.9 C (16.0 F)
2021
15.0 C (59.0 F)
Wettest day (Rx1day)
The wettest day of the year at Portal 4 SW, 1965 to 2021. The record is 106.7 mm (4.2 in) in 1996, marked on the chart; the median year is 42.9 mm (1.7 in).
Wettest day (Rx1day) at Portal 4 SW by year
Year
Wettest day (Rx1day)
1965
44.5 mm (1.8 in)
1966
41.4 mm (1.6 in)
1967
70.9 mm (2.8 in)
1968
50.8 mm (2.0 in)
1969
37.1 mm (1.5 in)
1970
26.2 mm (1.0 in)
1971
34.5 mm (1.4 in)
1972
41.1 mm (1.6 in)
1973
26.7 mm (1.1 in)
1974
24.6 mm (1.0 in)
1975
64.8 mm (2.6 in)
1976
50.8 mm (2.0 in)
1977
34.3 mm (1.4 in)
1978
40.1 mm (1.6 in)
1979
44.2 mm (1.7 in)
1980
51.8 mm (2.0 in)
1981
48.0 mm (1.9 in)
1982
42.9 mm (1.7 in)
1983
48.8 mm (1.9 in)
1984
32.3 mm (1.3 in)
1985
54.4 mm (2.1 in)
1986
103.1 mm (4.1 in)
1987
74.4 mm (2.9 in)
1988
73.2 mm (2.9 in)
1989
37.8 mm (1.5 in)
1990
63.2 mm (2.5 in)
1991
54.9 mm (2.2 in)
1992
50.8 mm (2.0 in)
1993
40.6 mm (1.6 in)
1994
71.1 mm (2.8 in)
1995
35.8 mm (1.4 in)
1996
106.7 mm (4.2 in)
1997
39.9 mm (1.6 in)
1998
40.6 mm (1.6 in)
1999
44.2 mm (1.7 in)
2000
63.5 mm (2.5 in)
2001
45.0 mm (1.8 in)
2002
36.3 mm (1.4 in)
2003
33.8 mm (1.3 in)
2004
40.6 mm (1.6 in)
2005
41.9 mm (1.6 in)
2006
31.8 mm (1.3 in)
2007
50.8 mm (2.0 in)
2008
58.9 mm (2.3 in)
2009
26.7 mm (1.1 in)
2010
77.5 mm (3.1 in)
2011
35.3 mm (1.4 in)
2012
45.7 mm (1.8 in)
2013
33.5 mm (1.3 in)
2014
46.0 mm (1.8 in)
2015
59.2 mm (2.3 in)
2016
63.0 mm (2.5 in)
2017
31.0 mm (1.2 in)
2018
41.9 mm (1.6 in)
2019
25.4 mm (1.0 in)
2020
41.7 mm (1.6 in)
2021
33.5 mm (1.3 in)
Wettest five days (Rx5day)
The wettest five days of the year at Portal 4 SW, 1965 to 2021. The record is 165.1 mm (6.5 in) in 1967, marked on the chart; the median year is 77.0 mm (3.0 in).
Wettest five days (Rx5day) at Portal 4 SW by year
Year
Wettest five days (Rx5day)
1965
76.4 mm (3.0 in)
1966
78.5 mm (3.1 in)
1967
165.1 mm (6.5 in)
1968
85.7 mm (3.4 in)
1969
67.9 mm (2.7 in)
1970
49.3 mm (1.9 in)
1971
62.3 mm (2.5 in)
1972
89.9 mm (3.5 in)
1973
80.8 mm (3.2 in)
1974
46.6 mm (1.8 in)
1975
100.9 mm (4.0 in)
1976
83.7 mm (3.3 in)
1977
65.6 mm (2.6 in)
1978
87.5 mm (3.4 in)
1979
68.2 mm (2.7 in)
1980
71.4 mm (2.8 in)
1981
67.6 mm (2.7 in)
1982
64.8 mm (2.6 in)
1983
135.4 mm (5.3 in)
1984
57.2 mm (2.3 in)
1985
59.8 mm (2.4 in)
1986
115.1 mm (4.5 in)
1987
76.4 mm (3.0 in)
1988
107.7 mm (4.2 in)
1989
79.2 mm (3.1 in)
1990
97.2 mm (3.8 in)
1991
76.2 mm (3.0 in)
1992
66.0 mm (2.6 in)
1993
91.6 mm (3.6 in)
1994
152.2 mm (6.0 in)
1995
72.9 mm (2.9 in)
1996
120.9 mm (4.8 in)
1997
63.5 mm (2.5 in)
1998
75.4 mm (3.0 in)
1999
77.5 mm (3.1 in)
2000
90.0 mm (3.5 in)
2001
50.2 mm (2.0 in)
2002
52.4 mm (2.1 in)
2003
38.7 mm (1.5 in)
2004
58.1 mm (2.3 in)
2005
77.8 mm (3.1 in)
2006
72.0 mm (2.8 in)
2007
102.9 mm (4.1 in)
2008
120.2 mm (4.7 in)
2009
79.8 mm (3.1 in)
2010
81.8 mm (3.2 in)
2011
52.8 mm (2.1 in)
2012
66.3 mm (2.6 in)
2013
87.6 mm (3.4 in)
2014
138.5 mm (5.5 in)
2015
81.1 mm (3.2 in)
2016
111.7 mm (4.4 in)
2017
81.3 mm (3.2 in)
2018
63.3 mm (2.5 in)
2019
19.0 mm (0.7 in)
2020
59.0 mm (2.3 in)
2021
n/a
Longest dry spell (CDD)
The longest dry spell of the year at Portal 4 SW, 1965 to 2021. The record is 148 days in 1972, marked on the chart; the median year is 52 days.
Longest dry spell (CDD) at Portal 4 SW by year
Year
Longest dry spell (CDD)
1965
65 days
1966
43 days
1967
40 days
1968
40 days
1969
57 days
1970
53 days
1971
52 days
1972
148 days
1973
59 days
1974
83 days
1975
40 days
1976
38 days
1977
54 days
1978
51 days
1979
52 days
1980
59 days
1981
37 days
1982
50 days
1983
82 days
1984
83 days
1985
27 days
1986
35 days
1987
28 days
1988
50 days
1989
69 days
1990
44 days
1991
66 days
1992
29 days
1993
46 days
1994
31 days
1995
38 days
1996
63 days
1997
27 days
1998
65 days
1999
75 days
2000
65 days
2001
37 days
2002
68 days
2003
45 days
2004
45 days
2005
55 days
2006
35 days
2007
53 days
2008
91 days
2009
33 days
2010
52 days
2011
80 days
2012
56 days
2013
58 days
2014
55 days
2015
25 days
2016
56 days
2017
46 days
2018
80 days
2019
13 days
2020
14 days
2021
n/a
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
43 years with a frost
Across 43 years with a frost, the median last spring frost at Portal 4 SW falls on 12 May and the median first autumn frost on 17 October, which leaves a median of 158 days between them.
Fitted over all years, the growing season changes by +5.7 days per decade at this station.
Frost dates and growing season at Portal 4 SW
Measure
Median, all years
Earliest period
Recent period (1979 to 2017)
Recent against earliest
Fitted trend
Last spring frost
12 May
n/a
12 May
n/a
-2.3 days per decade
First autumn frost
17 October
n/a
18 October
n/a
+3.3 days per decade
Growing days
158 days
n/a
168 days
n/a
+5.7 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
51 years, 1966 to 2017
A day with at least 44.2 mm (1.7 in) of rain is expected about once in 2 years. A day with at least 114.4 mm (4.5 in) of rain is expected about once in 100 years.
Rainfall return levels at Portal 4 SW: the daily rain expected about once in a given number of years
Expected about once in
A day with at least
Note
2 years
44.2 mm (1.7 in)
5 years
59.3 mm (2.3 in)
10 years
70.6 mm (2.8 in)
25 years
86.7 mm (3.4 in)
50 years
99.9 mm (3.9 in)
100 years
114.4 mm (4.5 in)
Longer than the 51 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, 51 years of values from 1966 to 2017.
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: 106.7 mm (4.2 in) in 1996; 103.1 mm (4.1 in) in 1986; 77.5 mm (3.1 in) in 2010.
Station Changes
2 suspected
2 changes were suspected in the annual mean temperature of Portal 4 SW, at 1989 and 2011. Each is measured against neighbouring stations.
Relative to 5 neighbouring stations, the station's annual mean temperature from 1989 ran 0.3 C (0.6 F) lower than in the years before (possible change).
Relative to 5 neighbouring stations, the station's annual mean temperature from 2011 ran 0.7 C (1.3 F) higher than in the years before (possible change).
Suspected changes in the annual mean temperature at Portal 4 SW, against neighbouring stations
Year
Shift (C)
Shift (F)
Strength
Neighbours
1989
-0.3
-0.6
possible
5
2011
+0.7
+1.3
possible
5
Possible change at the station (a move, a new instrument or a new site); the record is kept as measured. A "likely" change has a larger test statistic than a "possible" one. Neither says why the station differs from its neighbours. How changes are found, and the largest ones.
Download the Data
Data for Portal 4 SW standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Portal 4 SW 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 2026-10-14 (14 October 2026). Records are computed by this site and are not official.