Record envelope, standing records and threshold days for Charles Mill Lake (USC00331466), Ohio, United States, with 49 years of record.
Key Facts for Charles Mill Lake
Charles Mill Lake (USC00331466) is a weather station in Ohio, United States at 40.74 latitude and -82.36 longitude, 312 m (1,025 ft) above sea level.
The station reports from 1939 to 1987, 49 years of record.
1,464 records set at Charles Mill Lake still stand.
Records are tracked for tmax, tmin, prcp, snow, snwd: an element needs 30 years of data to be eligible.
Charles Mill Lake tied a daily record high maximum temperature of 32.8 C (91.0 F) on 24 July 1987.
About the Station
Location: Ohio, United States, 40.74 latitude, -82.36 longitude.
Elevation: 312 m (1,025 ft).
Period of record: 1939 to 1987, 49 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 Charles Mill Lake. 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 Charles Mill Lake, with 2026 drawn through them
Month
Highest record high
Lowest record low
2026 highest maximum
2026 lowest minimum
Jan
22.2 C (72.0 F)
-32.2 C (-26.0 F)
n/a
n/a
Feb
21.1 C (70.0 F)
-33.3 C (-27.9 F)
n/a
n/a
Mar
27.2 C (81.0 F)
-27.8 C (-18.0 F)
n/a
n/a
Apr
31.1 C (88.0 F)
-17.2 C (1.0 F)
n/a
n/a
May
32.8 C (91.0 F)
-7.2 C (19.0 F)
n/a
n/a
Jun
37.8 C (100.0 F)
-1.1 C (30.0 F)
n/a
n/a
Jul
37.2 C (99.0 F)
3.3 C (37.9 F)
n/a
n/a
Aug
37.2 C (99.0 F)
0.6 C (33.1 F)
n/a
n/a
Sep
37.8 C (100.0 F)
-3.9 C (25.0 F)
n/a
n/a
Oct
31.1 C (88.0 F)
-11.1 C (12.0 F)
n/a
n/a
Nov
26.7 C (80.1 F)
-20.0 C (-4.0 F)
n/a
n/a
Dec
23.3 C (73.9 F)
-26.7 C (-16.1 F)
n/a
n/a
Which Years Hold Standing Records
1,464 standing records
Year with most
1,464 records at Charles Mill Lake still stand. 1963 holds the most, with 54.
Standing records at Charles Mill Lake by the year they were set
Year set
Standing records
1939
40
1940
44
1941
44
1942
28
1943
29
1944
31
1945
37
1946
38
1947
36
1948
25
1949
46
1950
45
1951
25
1952
42
1953
42
1954
34
1955
23
1956
32
1957
20
1958
29
1959
32
1960
23
1961
19
1962
31
1963
54
1964
37
1965
32
1966
25
1967
28
1968
24
1969
21
1970
15
1971
16
1972
32
1973
18
1974
26
1975
25
1976
31
1977
38
1978
26
1979
29
1980
20
1981
21
1982
28
1983
28
1984
34
1985
22
1986
34
1987
5
All-Time Record Progression
3 new records
3 all-time records were set at Charles Mill Lake between 5 July 1969 and 25 December 1983. Each dot is a new record.
When Charles Mill Lake set new all-time records
Date
Kind
Detail
1969-07-05
Record daily precipitation
Record daily precipitation 157.5 mm (6.2 in)
1970-01-09
Record low maximum temperature
Record low maximum temperature -20.0 C (-4.0 F)
1983-12-25
Record low maximum temperature
Record low maximum temperature -24.4 C (-11.9 F)
Wettest Day of Each Month
Jul: 157.5 mm (6.2 in)
The wettest day on record for each calendar month at Charles Mill Lake. The most was 157.5 mm (6.2 in) on 5 July 1969.
Record daily precipitation for each month at Charles Mill Lake
Month
Record daily precipitation (mm)
Date
Jan
52.8 mm (2.1 in)
21 January 1959
Feb
52.1 mm (2.1 in)
10 February 1959
Mar
62.7 mm (2.5 in)
12 March 1939
Apr
50.0 mm (2.0 in)
27 April 1959
May
79.5 mm (3.1 in)
19 May 1969
Jun
92.2 mm (3.6 in)
12 June 1946
Jul
157.5 mm (6.2 in)
5 July 1969
Aug
74.9 mm (2.9 in)
1 August 1950
Sep
108.7 mm (4.3 in)
14 September 1979
Oct
56.4 mm (2.2 in)
7 October 1941
Nov
68.6 mm (2.7 in)
16 November 1955
Dec
49.3 mm (1.9 in)
28 December 1968
Period of Record Coverage
1939 to 1987
Complete yearUnder 90 percent of days
49 years of record at Charles Mill Lake, 1939 to 1987. 3 years have data for under 90 percent of days and are left out of rankings: 1978, 1979, 1987.
Cooler than the station meanWarmer than the station mean
One stripe for each of 44 complete years at Charles Mill Lake, 1939 to 1986. Blue stripes are years cooler than the station's own mean of 9.1 C (48.3 F); red stripes are warmer. The coolest year was 1963, at 7.3 C (45.2 F), and the warmest was 1949, at 10.9 C (51.6 F). The strongest colour marks a difference of 1.9 C (3.4 F).
Annual mean temperature at Charles Mill Lake as warming stripes, 1939 to 1986
Year
Annual mean temperature
Difference from the station mean
1939
10.6 C
+1.49 C
1940
8.1 C
-0.96 C
1941
9.7 C
+0.60 C
1942
9.2 C
+0.12 C
1943
9.2 C
+0.17 C
1944
9.8 C
+0.70 C
1945
9.1 C
+0.07 C
1946
10.2 C
+1.14 C
1947
9.5 C
+0.44 C
1948
9.8 C
+0.74 C
1949
10.9 C
+1.85 C
1951
9.3 C
+0.26 C
1952
10.4 C
+1.29 C
1953
10.5 C
+1.44 C
1954
10.1 C
+1.01 C
1955
9.9 C
+0.83 C
1956
9.4 C
+0.33 C
1957
9.4 C
+0.36 C
1958
8.2 C
-0.83 C
1959
9.5 C
+0.45 C
1960
8.7 C
-0.38 C
1961
8.9 C
-0.20 C
1962
8.3 C
-0.75 C
1963
7.3 C
-1.73 C
1964
8.8 C
-0.31 C
1965
8.8 C
-0.26 C
1966
8.2 C
-0.82 C
1967
8.3 C
-0.75 C
1968
8.3 C
-0.78 C
1969
8.3 C
-0.81 C
1970
8.7 C
-0.35 C
1971
8.6 C
-0.44 C
1972
7.9 C
-1.16 C
1973
9.7 C
+0.60 C
1974
8.6 C
-0.45 C
1975
9.0 C
-0.05 C
1976
7.9 C
-1.20 C
1977
8.6 C
-0.43 C
1981
8.5 C
-0.58 C
1982
8.7 C
-0.40 C
1983
9.2 C
+0.10 C
1984
8.7 C
-0.36 C
1985
8.6 C
-0.44 C
1986
9.5 C
+0.47 C
The annual mean temperature here has fallen by 0.3 C (0.1 to 0.4) per decade over 1939 to 1986. In Fahrenheit: 0.5 F (0.2 to 0.8) per decade. The slope is a straight line fitted to 44 complete years; the brackets give its 95 percent interval.
Fitted temperature trends per decade at Charles Mill Lake
Measure
Per decade (C)
Per decade (F)
Period
Complete years
Reading
Annual mean temperature
-0.3 C (-0.4 to -0.1) per decade
-0.5 F (-0.8 to -0.2) per decade
1939 to 1986
44
Fall
Mean daily maximum
-0.3 C (-0.4 to -0.1) per decade
-0.5 F (-0.8 to -0.2) per decade
1939 to 1986
44
Fall
Mean daily minimum
-0.3 C (-0.5 to -0.1) per decade
-0.5 F (-0.9 to -0.2) per decade
1939 to 1986
44
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
1939 to 1987
Yearly extremes at Charles Mill Lake: the record and the median year
Measure
Record
Year of the record
Median year
Years with a value
Hottest day (TXx)
37.8 C (100.0 F)
1952
34.4 C (93.9 F)
49
Coldest night (TNn)
-33.3 C (-27.9 F)
1963
-25.0 C (-13.0 F)
49
Wettest day (Rx1day)
157.5 mm (6.2 in)
1969
52.1 mm (2.1 in)
49
Wettest five days (Rx5day)
189.8 mm (7.5 in)
1969
82.1 mm (3.2 in)
49
Longest dry spell (CDD)
40 days
1963
16 days
49
Hottest day (TXx)
The hottest day of the year at Charles Mill Lake, 1939 to 1987. The record is 37.8 C (100.0 F) in 1952, marked on the chart; the median year is 34.4 C (93.9 F).
Hottest day (TXx) at Charles Mill Lake by year
Year
Hottest day (TXx)
1939
36.7 C (98.1 F)
1940
35.6 C (96.1 F)
1941
37.2 C (99.0 F)
1942
35.6 C (96.1 F)
1943
34.4 C (93.9 F)
1944
36.1 C (97.0 F)
1945
33.9 C (93.0 F)
1946
33.3 C (91.9 F)
1947
34.4 C (93.9 F)
1948
37.2 C (99.0 F)
1949
35.0 C (95.0 F)
1950
32.8 C (91.0 F)
1951
33.9 C (93.0 F)
1952
37.8 C (100.0 F)
1953
37.8 C (100.0 F)
1954
36.7 C (98.1 F)
1955
35.0 C (95.0 F)
1956
33.3 C (91.9 F)
1957
34.4 C (93.9 F)
1958
32.2 C (90.0 F)
1959
35.0 C (95.0 F)
1960
32.8 C (91.0 F)
1961
32.2 C (90.0 F)
1962
33.9 C (93.0 F)
1963
33.9 C (93.0 F)
1964
35.0 C (95.0 F)
1965
36.7 C (98.1 F)
1966
35.0 C (95.0 F)
1967
33.3 C (91.9 F)
1968
33.3 C (91.9 F)
1969
32.2 C (90.0 F)
1970
34.4 C (93.9 F)
1971
36.1 C (97.0 F)
1972
33.3 C (91.9 F)
1973
34.4 C (93.9 F)
1974
33.9 C (93.0 F)
1975
36.1 C (97.0 F)
1976
32.2 C (90.0 F)
1977
34.4 C (93.9 F)
1978
33.9 C (93.0 F)
1979
31.7 C (89.1 F)
1980
35.0 C (95.0 F)
1981
33.3 C (91.9 F)
1982
32.2 C (90.0 F)
1983
35.0 C (95.0 F)
1984
32.8 C (91.0 F)
1985
32.2 C (90.0 F)
1986
32.8 C (91.0 F)
1987
33.3 C (91.9 F)
Coldest night (TNn)
The coldest night of the year at Charles Mill Lake, 1939 to 1987. The record is -33.3 C (-27.9 F) in 1963, marked on the chart; the median year is -25.0 C (-13.0 F).
Coldest night (TNn) at Charles Mill Lake by year
Year
Coldest night (TNn)
1939
-15.6 C (3.9 F)
1940
-26.1 C (-15.0 F)
1941
-19.4 C (-2.9 F)
1942
-24.4 C (-11.9 F)
1943
-21.1 C (-6.0 F)
1944
-25.6 C (-14.1 F)
1945
-24.4 C (-11.9 F)
1946
-22.2 C (-8.0 F)
1947
-19.4 C (-2.9 F)
1948
-29.4 C (-20.9 F)
1949
-17.2 C (1.0 F)
1950
-24.4 C (-11.9 F)
1951
-26.1 C (-15.0 F)
1952
-18.9 C (-2.0 F)
1953
-20.0 C (-4.0 F)
1954
-21.1 C (-6.0 F)
1955
-21.1 C (-6.0 F)
1956
-19.4 C (-2.9 F)
1957
-22.2 C (-8.0 F)
1958
-26.7 C (-16.1 F)
1959
-25.0 C (-13.0 F)
1960
-22.2 C (-8.0 F)
1961
-27.2 C (-17.0 F)
1962
-24.4 C (-11.9 F)
1963
-33.3 C (-27.9 F)
1964
-26.1 C (-15.0 F)
1965
-26.7 C (-16.1 F)
1966
-25.0 C (-13.0 F)
1967
-26.7 C (-16.1 F)
1968
-26.1 C (-15.0 F)
1969
-21.1 C (-6.0 F)
1970
-25.6 C (-14.1 F)
1971
-23.3 C (-9.9 F)
1972
-25.6 C (-14.1 F)
1973
-22.8 C (-9.0 F)
1974
-22.2 C (-8.0 F)
1975
-26.7 C (-16.1 F)
1976
-25.0 C (-13.0 F)
1977
-28.9 C (-20.0 F)
1978
-27.2 C (-17.0 F)
1979
-28.3 C (-18.9 F)
1980
-23.9 C (-11.0 F)
1981
-26.1 C (-15.0 F)
1982
-28.3 C (-18.9 F)
1983
-26.1 C (-15.0 F)
1984
-32.2 C (-26.0 F)
1985
-31.1 C (-24.0 F)
1986
-21.1 C (-6.0 F)
1987
-21.1 C (-6.0 F)
Wettest day (Rx1day)
The wettest day of the year at Charles Mill Lake, 1939 to 1987. The record is 157.5 mm (6.2 in) in 1969, marked on the chart; the median year is 52.1 mm (2.1 in).
Wettest day (Rx1day) at Charles Mill Lake by year
Year
Wettest day (Rx1day)
1939
62.7 mm (2.5 in)
1940
49.8 mm (2.0 in)
1941
56.4 mm (2.2 in)
1942
78.0 mm (3.1 in)
1943
54.6 mm (2.1 in)
1944
51.6 mm (2.0 in)
1945
46.2 mm (1.8 in)
1946
92.2 mm (3.6 in)
1947
57.2 mm (2.3 in)
1948
41.9 mm (1.6 in)
1949
61.5 mm (2.4 in)
1950
74.9 mm (2.9 in)
1951
71.4 mm (2.8 in)
1952
44.5 mm (1.8 in)
1953
46.0 mm (1.8 in)
1954
26.2 mm (1.0 in)
1955
68.6 mm (2.7 in)
1956
40.6 mm (1.6 in)
1957
97.8 mm (3.9 in)
1958
65.0 mm (2.6 in)
1959
63.0 mm (2.5 in)
1960
28.2 mm (1.1 in)
1961
41.9 mm (1.6 in)
1962
39.4 mm (1.6 in)
1963
46.5 mm (1.8 in)
1964
62.2 mm (2.4 in)
1965
40.9 mm (1.6 in)
1966
60.2 mm (2.4 in)
1967
37.3 mm (1.5 in)
1968
52.8 mm (2.1 in)
1969
157.5 mm (6.2 in)
1970
40.4 mm (1.6 in)
1971
74.9 mm (2.9 in)
1972
73.7 mm (2.9 in)
1973
41.1 mm (1.6 in)
1974
41.4 mm (1.6 in)
1975
48.0 mm (1.9 in)
1976
33.8 mm (1.3 in)
1977
52.1 mm (2.1 in)
1978
37.1 mm (1.5 in)
1979
108.7 mm (4.3 in)
1980
50.3 mm (2.0 in)
1981
85.6 mm (3.4 in)
1982
74.2 mm (2.9 in)
1983
43.2 mm (1.7 in)
1984
57.2 mm (2.3 in)
1985
50.8 mm (2.0 in)
1986
49.8 mm (2.0 in)
1987
113.0 mm (4.4 in)
Wettest five days (Rx5day)
The wettest five days of the year at Charles Mill Lake, 1939 to 1987. The record is 189.8 mm (7.5 in) in 1969, marked on the chart; the median year is 82.1 mm (3.2 in).
Wettest five days (Rx5day) at Charles Mill Lake by year
Year
Wettest five days (Rx5day)
1939
70.1 mm (2.8 in)
1940
86.9 mm (3.4 in)
1941
102.2 mm (4.0 in)
1942
87.7 mm (3.5 in)
1943
62.0 mm (2.4 in)
1944
82.1 mm (3.2 in)
1945
72.6 mm (2.9 in)
1946
140.7 mm (5.5 in)
1947
83.2 mm (3.3 in)
1948
72.0 mm (2.8 in)
1949
62.3 mm (2.5 in)
1950
84.8 mm (3.3 in)
1951
71.4 mm (2.8 in)
1952
61.9 mm (2.4 in)
1953
73.9 mm (2.9 in)
1954
67.7 mm (2.7 in)
1955
79.3 mm (3.1 in)
1956
73.8 mm (2.9 in)
1957
168.0 mm (6.6 in)
1958
96.8 mm (3.8 in)
1959
107.0 mm (4.2 in)
1960
41.2 mm (1.6 in)
1961
83.1 mm (3.3 in)
1962
81.6 mm (3.2 in)
1963
65.0 mm (2.6 in)
1964
99.3 mm (3.9 in)
1965
71.4 mm (2.8 in)
1966
100.1 mm (3.9 in)
1967
51.4 mm (2.0 in)
1968
90.1 mm (3.5 in)
1969
189.8 mm (7.5 in)
1970
83.4 mm (3.3 in)
1971
90.9 mm (3.6 in)
1972
98.3 mm (3.9 in)
1973
70.7 mm (2.8 in)
1974
66.8 mm (2.6 in)
1975
81.5 mm (3.2 in)
1976
48.7 mm (1.9 in)
1977
70.6 mm (2.8 in)
1978
62.4 mm (2.5 in)
1979
113.3 mm (4.5 in)
1980
79.4 mm (3.1 in)
1981
108.4 mm (4.3 in)
1982
101.4 mm (4.0 in)
1983
106.7 mm (4.2 in)
1984
59.5 mm (2.3 in)
1985
85.1 mm (3.4 in)
1986
98.3 mm (3.9 in)
1987
139.1 mm (5.5 in)
Longest dry spell (CDD)
The longest dry spell of the year at Charles Mill Lake, 1939 to 1987. The record is 40 days in 1963, marked on the chart; the median year is 16 days.
Longest dry spell (CDD) at Charles Mill Lake by year
Year
Longest dry spell (CDD)
1939
21 days
1940
14 days
1941
14 days
1942
20 days
1943
20 days
1944
15 days
1945
24 days
1946
18 days
1947
13 days
1948
18 days
1949
16 days
1950
12 days
1951
19 days
1952
19 days
1953
25 days
1954
13 days
1955
16 days
1956
16 days
1957
21 days
1958
18 days
1959
15 days
1960
12 days
1961
14 days
1962
17 days
1963
40 days
1964
20 days
1965
20 days
1966
16 days
1967
25 days
1968
17 days
1969
29 days
1970
15 days
1971
14 days
1972
15 days
1973
14 days
1974
17 days
1975
15 days
1976
26 days
1977
16 days
1978
13 days
1979
11 days
1980
15 days
1981
25 days
1982
12 days
1983
24 days
1984
9 days
1985
13 days
1986
14 days
1987
17 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
44 years with a frost
Across 44 years with a frost, the median last spring frost at Charles Mill Lake falls on 14 May and the median first autumn frost on 1 October, which leaves a median of 140 days between them.
Fitted over all years, the growing season changes by -0.5 days per decade at this station.
Frost dates and growing season at Charles Mill Lake
Measure
Median, all years
Earliest period
Recent period (1954 to 1986)
Recent against earliest
Fitted trend
Last spring frost
14 May
n/a
18 May
n/a
+1.0 days per decade
First autumn frost
1 October
n/a
2 October
n/a
+0.6 days per decade
Growing days
140 days
n/a
138 days
n/a
-0.5 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
48 years, 1939 to 1986
A day with at least 52.3 mm (2.1 in) of rain is expected about once in 2 years. A day with at least 144.5 mm (5.7 in) of rain is expected about once in 100 years.
Rainfall return levels at Charles Mill Lake: the daily rain expected about once in a given number of years
Expected about once in
A day with at least
Note
2 years
52.3 mm (2.1 in)
5 years
70.8 mm (2.8 in)
10 years
85.2 mm (3.4 in)
25 years
106.3 mm (4.2 in)
50 years
124.3 mm (4.9 in)
Longer than the 48 years of record
100 years
144.5 mm (5.7 in)
Longer than the 48 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, 48 years of values from 1939 to 1986.
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: 157.5 mm (6.2 in) in 1969; 108.7 mm (4.3 in) in 1979; 97.8 mm (3.9 in) in 1957.
Station Changes
1 suspected
One change was suspected in the annual mean temperature of Charles Mill Lake, at 1957. Each is measured against neighbouring stations.
Relative to 5 neighbouring stations, the station's annual mean temperature from 1957 ran 0.3 C (0.5 F) lower than in the years before (likely change).
Suspected changes in the annual mean temperature at Charles Mill Lake, against neighbouring stations
Year
Shift (C)
Shift (F)
Strength
Neighbours
1957
-0.2
-0.4
likely
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 Charles Mill Lake standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Charles Mill Lake 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.