Record envelope, standing records and threshold days for Reading 4 NNW (USC00367322), Pennsylvania, United States, with 40 years of record.
Key Facts for Reading 4 NNW
Reading 4 NNW (USC00367322) is a weather station in Pennsylvania, United States at 40.43 latitude and -75.93 longitude, 110 m (360 ft) above sea level.
The station reports from 1969 to 2008, 40 years of record.
1,464 records set at Reading 4 NNW still stand.
Records are tracked for tmax, tmin, prcp, snow, snwd: an element needs 30 years of data to be eligible.
Reading 4 NNW set a daily record precipitation of 40.9 mm (1.6 in) on 5 March 2008.
About the Station
Location: Pennsylvania, United States, 40.43 latitude, -75.93 longitude.
Elevation: 110 m (360 ft).
Period of record: 1969 to 2008, 40 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 Reading 4 NNW. 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 Reading 4 NNW, with 2026 drawn through them
Month
Highest record high
Lowest record low
2026 highest maximum
2026 lowest minimum
Jan
21.7 C (71.1 F)
-28.9 C (-20.0 F)
n/a
n/a
Feb
25.0 C (77.0 F)
-22.2 C (-8.0 F)
n/a
n/a
Mar
31.1 C (88.0 F)
-18.9 C (-2.0 F)
n/a
n/a
Apr
36.1 C (97.0 F)
-8.9 C (16.0 F)
n/a
n/a
May
35.6 C (96.1 F)
-3.3 C (26.1 F)
n/a
n/a
Jun
36.1 C (97.0 F)
2.2 C (36.0 F)
n/a
n/a
Jul
38.9 C (102.0 F)
7.8 C (46.0 F)
n/a
n/a
Aug
38.9 C (102.0 F)
5.6 C (42.1 F)
n/a
n/a
Sep
37.8 C (100.0 F)
-1.1 C (30.0 F)
n/a
n/a
Oct
33.3 C (91.9 F)
-6.7 C (19.9 F)
n/a
n/a
Nov
27.8 C (82.0 F)
-13.3 C (8.1 F)
n/a
n/a
Dec
25.0 C (77.0 F)
-20.0 C (-4.0 F)
n/a
n/a
Which Years Hold Standing Records
1,464 standing records
Year with most
1,464 records at Reading 4 NNW still stand. 1976 holds the most, with 71.
Standing records at Reading 4 NNW by the year they were set
Year set
Standing records
1969
17
1970
34
1971
40
1972
38
1973
28
1974
34
1975
35
1976
71
1977
43
1978
37
1979
64
1980
37
1981
28
1982
44
1983
37
1984
46
1985
33
1986
39
1987
26
1988
38
1989
53
1990
44
1991
39
1992
33
1993
41
1994
26
1995
34
1996
42
1997
21
1998
41
1999
39
2000
39
2001
30
2002
52
2003
26
2004
25
2005
35
2006
35
2007
37
2008
3
All-Time Record Progression
2 new records
2 all-time records were set at Reading 4 NNW between 17 February 2003 and 19 February 2003. Each dot is a new record.
When Reading 4 NNW set new all-time records
Date
Kind
Detail
2003-02-17
Record daily snowfall
Record daily snowfall 55.9 cm (22.0 in)
2003-02-19
Record snow depth
Record snow depth 53.3 cm (21.0 in)
Wettest Day of Each Month
Jun: 164.8 mm (6.5 in)
The wettest day on record for each calendar month at Reading 4 NNW. The most was 164.8 mm (6.5 in) on 23 June 1972.
Record daily precipitation for each month at Reading 4 NNW
Month
Record daily precipitation (mm)
Date
Jan
54.1 mm (2.1 in)
8 January 1979
Feb
64.8 mm (2.6 in)
14 February 2007
Mar
120.7 mm (4.8 in)
17 March 2004
Apr
59.2 mm (2.3 in)
2 April 1970
May
95.8 mm (3.8 in)
6 May 1989
Jun
164.8 mm (6.5 in)
23 June 1972
Jul
110.5 mm (4.4 in)
26 July 2001
Aug
103.6 mm (4.1 in)
22 August 1994
Sep
158.8 mm (6.3 in)
9 September 1987
Oct
118.1 mm (4.6 in)
9 October 2005
Nov
79.5 mm (3.1 in)
25 November 1971
Dec
81.8 mm (3.2 in)
13 December 1983
Period of Record Coverage
1969 to 2008
Complete yearUnder 90 percent of days
40 years of record at Reading 4 NNW, 1969 to 2008. 2 years have data for under 90 percent of days and are left out of rankings: 1969, 2008.
Cooler than the station meanWarmer than the station mean
One stripe for each of 36 complete years at Reading 4 NNW, 1970 to 2007. Blue stripes are years cooler than the station's own mean of 11.3 C (52.3 F); red stripes are warmer. The coolest year was 1976, at 9.8 C (49.6 F), and the warmest was 1998, at 13.5 C (56.3 F). The strongest colour marks a difference of 2.2 C (4.0 F).
Annual mean temperature at Reading 4 NNW as warming stripes, 1970 to 2007
Year
Annual mean temperature
Difference from the station mean
1970
11.6 C
+0.28 C
1972
10.3 C
-0.97 C
1973
11.6 C
+0.35 C
1974
11.0 C
-0.30 C
1975
11.0 C
-0.30 C
1976
9.8 C
-1.49 C
1977
10.4 C
-0.90 C
1978
10.0 C
-1.31 C
1979
10.8 C
-0.51 C
1980
10.9 C
-0.42 C
1981
10.5 C
-0.75 C
1982
10.5 C
-0.79 C
1983
11.4 C
+0.13 C
1984
11.1 C
-0.18 C
1985
11.5 C
+0.22 C
1986
11.2 C
-0.08 C
1988
10.5 C
-0.78 C
1989
10.2 C
-1.05 C
1990
12.1 C
+0.79 C
1991
12.0 C
+0.71 C
1992
10.1 C
-1.22 C
1993
10.6 C
-0.64 C
1994
10.5 C
-0.81 C
1995
11.2 C
-0.06 C
1996
11.0 C
-0.27 C
1997
11.5 C
+0.19 C
1998
13.5 C
+2.20 C
1999
12.7 C
+1.38 C
2000
11.5 C
+0.23 C
2001
12.2 C
+0.95 C
2002
12.6 C
+1.33 C
2003
11.1 C
-0.18 C
2004
11.8 C
+0.48 C
2005
12.2 C
+0.89 C
2006
13.1 C
+1.82 C
2007
12.4 C
+1.07 C
The annual mean temperature here has risen by 0.5 C (0.3 to 0.7) per decade over 1970 to 2007. In Fahrenheit: 0.9 F (0.5 to 1.3) per decade. The slope is a straight line fitted to 36 complete years; the brackets give its 95 percent interval.
Fitted temperature trends per decade at Reading 4 NNW
Measure
Per decade (C)
Per decade (F)
Period
Complete years
Reading
Annual mean temperature
0.5 C (0.3 to 0.7) per decade
0.9 F (0.5 to 1.3) per decade
1970 to 2007
36
Rise
Mean daily maximum
0.2 C (-0.1 to 0.4) per decade
0.3 F (-0.2 to 0.8) per decade
1970 to 2007
36
Not clearly different from zero
Mean daily minimum
0.8 C (0.6 to 1.0) per decade
1.4 F (1.0 to 1.9) per decade
1970 to 2007
36
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
1969 to 2008
Yearly extremes at Reading 4 NNW: the record and the median year
Measure
Record
Year of the record
Median year
Years with a value
Hottest day (TXx)
38.9 C (102.0 F)
1988
35.6 C (96.1 F)
40
Coldest night (TNn)
-28.9 C (-20.0 F)
1994
-16.7 C (1.9 F)
40
Wettest day (Rx1day)
164.8 mm (6.5 in)
1972
67.3 mm (2.6 in)
40
Wettest five days (Rx5day)
256.5 mm (10.1 in)
1972
101.3 mm (4.0 in)
40
Longest dry spell (CDD)
33 days
1998
17 days
40
Hottest day (TXx)
The hottest day of the year at Reading 4 NNW, 1969 to 2008. The record is 38.9 C (102.0 F) in 1988, marked on the chart; the median year is 35.6 C (96.1 F).
Hottest day (TXx) at Reading 4 NNW by year
Year
Hottest day (TXx)
1969
35.6 C (96.1 F)
1970
35.0 C (95.0 F)
1971
35.0 C (95.0 F)
1972
35.0 C (95.0 F)
1973
36.7 C (98.1 F)
1974
35.0 C (95.0 F)
1975
36.1 C (97.0 F)
1976
36.1 C (97.0 F)
1977
35.0 C (95.0 F)
1978
34.4 C (93.9 F)
1979
33.9 C (93.0 F)
1980
37.8 C (100.0 F)
1981
34.4 C (93.9 F)
1982
34.4 C (93.9 F)
1983
37.8 C (100.0 F)
1984
35.6 C (96.1 F)
1985
35.6 C (96.1 F)
1986
37.2 C (99.0 F)
1987
36.1 C (97.0 F)
1988
38.9 C (102.0 F)
1989
33.3 C (91.9 F)
1990
35.6 C (96.1 F)
1991
36.1 C (97.0 F)
1992
33.9 C (93.0 F)
1993
35.6 C (96.1 F)
1994
34.4 C (93.9 F)
1995
37.2 C (99.0 F)
1996
35.6 C (96.1 F)
1997
36.1 C (97.0 F)
1998
33.9 C (93.0 F)
1999
38.9 C (102.0 F)
2000
33.9 C (93.0 F)
2001
37.2 C (99.0 F)
2002
38.9 C (102.0 F)
2003
33.9 C (93.0 F)
2004
33.3 C (91.9 F)
2005
36.1 C (97.0 F)
2006
36.7 C (98.1 F)
2007
35.6 C (96.1 F)
2008
19.4 C (66.9 F)
Coldest night (TNn)
The coldest night of the year at Reading 4 NNW, 1969 to 2008. The record is -28.9 C (-20.0 F) in 1994, marked on the chart; the median year is -16.7 C (1.9 F).
Coldest night (TNn) at Reading 4 NNW by year
Year
Coldest night (TNn)
1969
-16.7 C (1.9 F)
1970
-21.1 C (-6.0 F)
1971
-16.1 C (3.0 F)
1972
-16.7 C (1.9 F)
1973
-14.4 C (6.1 F)
1974
-16.7 C (1.9 F)
1975
-17.8 C (0.0 F)
1976
-16.7 C (1.9 F)
1977
-22.8 C (-9.0 F)
1978
-18.9 C (-2.0 F)
1979
-22.2 C (-8.0 F)
1980
-20.0 C (-4.0 F)
1981
-22.8 C (-9.0 F)
1982
-23.3 C (-9.9 F)
1983
-20.0 C (-4.0 F)
1984
-24.4 C (-11.9 F)
1985
-22.8 C (-9.0 F)
1986
-15.6 C (3.9 F)
1987
-20.6 C (-5.1 F)
1988
-22.2 C (-8.0 F)
1989
-18.3 C (-0.9 F)
1990
-14.4 C (6.1 F)
1991
-14.4 C (6.1 F)
1992
-13.9 C (7.0 F)
1993
-16.1 C (3.0 F)
1994
-28.9 C (-20.0 F)
1995
-16.1 C (3.0 F)
1996
-20.6 C (-5.1 F)
1997
-16.7 C (1.9 F)
1998
-10.6 C (12.9 F)
1999
-13.3 C (8.1 F)
2000
-15.0 C (5.0 F)
2001
-15.6 C (3.9 F)
2002
-13.3 C (8.1 F)
2003
-16.1 C (3.0 F)
2004
-17.8 C (0.0 F)
2005
-18.9 C (-2.0 F)
2006
-11.1 C (12.0 F)
2007
-15.0 C (5.0 F)
2008
-13.3 C (8.1 F)
Wettest day (Rx1day)
The wettest day of the year at Reading 4 NNW, 1969 to 2008. The record is 164.8 mm (6.5 in) in 1972, marked on the chart; the median year is 67.3 mm (2.6 in).
Wettest day (Rx1day) at Reading 4 NNW by year
Year
Wettest day (Rx1day)
1969
90.7 mm (3.6 in)
1970
59.2 mm (2.3 in)
1971
79.5 mm (3.1 in)
1972
164.8 mm (6.5 in)
1973
96.0 mm (3.8 in)
1974
34.5 mm (1.4 in)
1975
72.4 mm (2.9 in)
1976
51.8 mm (2.0 in)
1977
45.2 mm (1.8 in)
1978
52.1 mm (2.1 in)
1979
71.1 mm (2.8 in)
1980
47.5 mm (1.9 in)
1981
60.2 mm (2.4 in)
1982
51.3 mm (2.0 in)
1983
81.8 mm (3.2 in)
1984
53.3 mm (2.1 in)
1985
94.0 mm (3.7 in)
1986
66.0 mm (2.6 in)
1987
158.8 mm (6.3 in)
1988
58.4 mm (2.3 in)
1989
95.8 mm (3.8 in)
1990
50.8 mm (2.0 in)
1991
66.0 mm (2.6 in)
1992
57.9 mm (2.3 in)
1993
56.1 mm (2.2 in)
1994
103.6 mm (4.1 in)
1995
73.7 mm (2.9 in)
1996
77.2 mm (3.0 in)
1997
43.7 mm (1.7 in)
1998
45.7 mm (1.8 in)
1999
90.7 mm (3.6 in)
2000
68.6 mm (2.7 in)
2001
110.5 mm (4.4 in)
2002
58.9 mm (2.3 in)
2003
95.0 mm (3.7 in)
2004
120.7 mm (4.8 in)
2005
118.1 mm (4.6 in)
2006
69.3 mm (2.7 in)
2007
64.8 mm (2.6 in)
2008
40.9 mm (1.6 in)
Wettest five days (Rx5day)
The wettest five days of the year at Reading 4 NNW, 1969 to 2008. The record is 256.5 mm (10.1 in) in 1972, marked on the chart; the median year is 101.3 mm (4.0 in).
Wettest five days (Rx5day) at Reading 4 NNW by year
Year
Wettest five days (Rx5day)
1969
138.5 mm (5.5 in)
1970
82.9 mm (3.3 in)
1971
101.1 mm (4.0 in)
1972
256.5 mm (10.1 in)
1973
115.1 mm (4.5 in)
1974
58.9 mm (2.3 in)
1975
167.5 mm (6.6 in)
1976
101.4 mm (4.0 in)
1977
81.8 mm (3.2 in)
1978
107.2 mm (4.2 in)
1979
126.5 mm (5.0 in)
1980
77.3 mm (3.0 in)
1981
72.9 mm (2.9 in)
1982
90.2 mm (3.6 in)
1983
119.4 mm (4.7 in)
1984
85.0 mm (3.3 in)
1985
139.5 mm (5.5 in)
1986
73.8 mm (2.9 in)
1987
204.2 mm (8.0 in)
1988
135.9 mm (5.4 in)
1989
137.7 mm (5.4 in)
1990
64.5 mm (2.5 in)
1991
74.9 mm (2.9 in)
1992
70.6 mm (2.8 in)
1993
82.1 mm (3.2 in)
1994
145.8 mm (5.7 in)
1995
84.3 mm (3.3 in)
1996
117.3 mm (4.6 in)
1997
68.9 mm (2.7 in)
1998
94.0 mm (3.7 in)
1999
142.8 mm (5.6 in)
2000
86.1 mm (3.4 in)
2001
113.0 mm (4.4 in)
2002
69.1 mm (2.7 in)
2003
139.7 mm (5.5 in)
2004
144.9 mm (5.7 in)
2005
202.0 mm (8.0 in)
2006
109.0 mm (4.3 in)
2007
64.8 mm (2.6 in)
2008
56.6 mm (2.2 in)
Longest dry spell (CDD)
The longest dry spell of the year at Reading 4 NNW, 1969 to 2008. The record is 33 days in 1998, marked on the chart; the median year is 17 days.
Longest dry spell (CDD) at Reading 4 NNW by year
Year
Longest dry spell (CDD)
1969
19 days
1970
17 days
1971
21 days
1972
11 days
1973
25 days
1974
15 days
1975
14 days
1976
22 days
1977
18 days
1978
19 days
1979
13 days
1980
27 days
1981
15 days
1982
16 days
1983
17 days
1984
17 days
1985
18 days
1986
15 days
1987
25 days
1988
23 days
1989
17 days
1990
17 days
1991
23 days
1992
18 days
1993
17 days
1994
14 days
1995
21 days
1996
17 days
1997
14 days
1998
33 days
1999
21 days
2000
21 days
2001
32 days
2002
19 days
2003
14 days
2004
16 days
2005
17 days
2006
17 days
2007
18 days
2008
11 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
36 years with a frost
Across 36 years with a frost, the median last spring frost at Reading 4 NNW falls on 23 April and the median first autumn frost on 19 October, which leaves a median of 177 days between them.
Fitted over all years, the growing season changes by +10.5 days per decade at this station.
Frost dates and growing season at Reading 4 NNW
Measure
Median, all years
Earliest period
Recent period (1977 to 2007)
Recent against earliest
Fitted trend
Last spring frost
23 April
n/a
20 April
n/a
-8.3 days per decade
First autumn frost
19 October
n/a
19 October
n/a
+2.3 days per decade
Growing days
177 days
n/a
179 days
n/a
+10.5 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, 1970 to 2007
A day with at least 67.9 mm (2.7 in) of rain is expected about once in 2 years. A day with at least 194.8 mm (7.7 in) of rain is expected about once in 100 years.
Rainfall return levels at Reading 4 NNW: the daily rain expected about once in a given number of years
Expected about once in
A day with at least
Note
2 years
67.9 mm (2.7 in)
5 years
93.7 mm (3.7 in)
10 years
113.7 mm (4.5 in)
25 years
142.7 mm (5.6 in)
50 years
167.3 mm (6.6 in)
Longer than the 37 years of record
100 years
194.8 mm (7.7 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 1970 to 2007.
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: 164.8 mm (6.5 in) in 1972; 158.8 mm (6.3 in) in 1987; 120.7 mm (4.8 in) in 2004.
Download the Data
Data for Reading 4 NNW standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Reading 4 NNW 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.