Record envelope, standing records and threshold days for Rock Hall (USC00187700), Maryland, United States, with 69 years of record.
Key Facts for Rock Hall
Rock Hall (USC00187700) is a weather station in Maryland, United States at 39.13 latitude and -76.23 longitude, 6 m (20 ft) above sea level.
The station reports from 1899 to 1967, 69 years of record.
1,464 records set at Rock Hall still stand.
Records are tracked for tmax, tmin, prcp: an element needs 30 years of data to be eligible.
Rock Hall set a daily record low minimum temperature of -9.4 C (15.1 F) on 19 March 1967.
About the Station
Location: Maryland, United States, 39.13 latitude, -76.23 longitude.
Elevation: 6 m (20 ft).
Period of record: 1899 to 1967, 69 years.
Eligible elements: tmax, tmin, prcp.
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 Rock Hall. 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 Rock Hall, with 2026 drawn through them
Month
Highest record high
Lowest record low
2026 highest maximum
2026 lowest minimum
Jan
23.3 C (73.9 F)
-20.6 C (-5.1 F)
n/a
n/a
Feb
25.6 C (78.1 F)
-25.6 C (-14.1 F)
n/a
n/a
Mar
30.0 C (86.0 F)
-15.6 C (3.9 F)
n/a
n/a
Apr
32.2 C (90.0 F)
-10.0 C (14.0 F)
n/a
n/a
May
36.7 C (98.1 F)
-0.6 C (30.9 F)
n/a
n/a
Jun
38.3 C (100.9 F)
2.8 C (37.0 F)
n/a
n/a
Jul
40.0 C (104.0 F)
8.9 C (48.0 F)
n/a
n/a
Aug
38.9 C (102.0 F)
7.2 C (45.0 F)
n/a
n/a
Sep
36.7 C (98.1 F)
0.6 C (33.1 F)
n/a
n/a
Oct
35.0 C (95.0 F)
-5.6 C (21.9 F)
n/a
n/a
Nov
29.4 C (84.9 F)
-13.9 C (7.0 F)
n/a
n/a
Dec
21.7 C (71.1 F)
-16.7 C (1.9 F)
n/a
n/a
Which Years Hold Standing Records
1,464 standing records
Year with most
1,464 records at Rock Hall still stand. 1930 holds the most, with 57.
Standing records at Rock Hall by the year they were set
Year set
Standing records
1899
46
1900
56
1901
33
1902
5
1919
14
1920
9
1921
11
1922
19
1923
29
1924
23
1925
40
1926
41
1927
44
1928
32
1929
46
1930
57
1931
30
1932
37
1933
37
1934
46
1935
34
1936
35
1937
32
1938
31
1939
25
1940
20
1941
27
1942
27
1943
32
1944
17
1945
36
1946
26
1947
35
1948
13
1949
15
1950
28
1951
28
1952
16
1953
25
1954
32
1955
17
1956
29
1957
27
1958
24
1959
20
1960
26
1961
11
1962
26
1963
18
1964
24
1965
23
1966
21
1967
9
Wettest Day of Each Month
Aug: 190.5 mm (7.5 in)
The wettest day on record for each calendar month at Rock Hall. The most was 190.5 mm (7.5 in) on 12 August 1928.
Record daily precipitation for each month at Rock Hall
Month
Record daily precipitation (mm)
Date
Jan
57.2 mm (2.3 in)
3 January 1936
Feb
55.1 mm (2.2 in)
17 February 1924
Mar
64.8 mm (2.6 in)
29 March 1942
Apr
73.7 mm (2.9 in)
16 April 1929
May
59.7 mm (2.4 in)
26 May 1946
Jun
79.8 mm (3.1 in)
19 June 1955
Jul
112.3 mm (4.4 in)
10 July 1931
Aug
190.5 mm (7.5 in)
12 August 1928
Sep
107.7 mm (4.2 in)
12 September 1960
Oct
86.4 mm (3.4 in)
19 October 1966
Nov
67.8 mm (2.7 in)
24 November 1901
Dec
51.8 mm (2.0 in)
29 December 1901
Period of Record Coverage
1899 to 1967
Complete yearUnder 90 percent of days
53 years of record at Rock Hall, 1899 to 1967. 13 years have data for under 90 percent of days and are left out of rankings: 1902, 1919, 1920, 1921, 1940, 1941, 1947, 1948 and others.
Cooler than the station meanWarmer than the station mean
One stripe for each of 37 complete years at Rock Hall, 1899 to 1966. Blue stripes are years cooler than the station's own mean of 13.1 C (55.7 F); red stripes are warmer. The coolest year was 1958, at 12.0 C (53.7 F), and the warmest was 1949, at 14.1 C (57.4 F). The strongest colour marks a difference of 1.2 C (2.2 F).
Annual mean temperature at Rock Hall as warming stripes, 1899 to 1966
Year
Annual mean temperature
Difference from the station mean
1899
12.3 C
-0.80 C
1900
13.5 C
+0.40 C
1901
12.1 C
-1.09 C
1922
13.5 C
+0.40 C
1923
13.2 C
+0.04 C
1924
12.1 C
-1.07 C
1925
13.0 C
-0.18 C
1926
12.1 C
-1.06 C
1927
13.2 C
+0.08 C
1928
13.0 C
-0.15 C
1929
13.2 C
+0.05 C
1931
14.0 C
+0.83 C
1932
13.4 C
+0.29 C
1933
13.3 C
+0.16 C
1934
12.9 C
-0.22 C
1935
13.0 C
-0.11 C
1936
12.9 C
-0.22 C
1937
13.1 C
-0.08 C
1938
13.5 C
+0.37 C
1939
13.5 C
+0.32 C
1943
13.2 C
+0.10 C
1944
13.1 C
-0.09 C
1945
13.3 C
+0.12 C
1946
13.8 C
+0.62 C
1949
14.1 C
+0.95 C
1950
12.8 C
-0.32 C
1951
13.3 C
+0.12 C
1952
13.3 C
+0.13 C
1953
14.0 C
+0.84 C
1954
13.6 C
+0.47 C
1955
13.0 C
-0.11 C
1956
12.8 C
-0.32 C
1957
13.3 C
+0.18 C
1958
12.0 C
-1.11 C
1959
13.6 C
+0.42 C
1964
13.2 C
+0.08 C
1966
13.3 C
+0.12 C
The fitted trend in annual mean temperature here over 1899 to 1966 is 0.09 C (-0.01 to 0.19) per decade. The interval includes zero, so the trend is not clearly different from zero. In Fahrenheit: 0.17 F (-0.01 to 0.35) per decade. The slope is a straight line fitted to 37 complete years; the brackets give its 95 percent interval.
Fitted temperature trends per decade at Rock Hall
Measure
Per decade (C)
Per decade (F)
Period
Complete years
Reading
Annual mean temperature
0.09 C (-0.01 to 0.19) per decade
0.17 F (-0.01 to 0.35) per decade
1899 to 1966
37
Not clearly different from zero
Mean daily maximum
0.10 C (-0.03 to 0.24) per decade
0.2 F (-0.1 to 0.4) per decade
1899 to 1966
37
Not clearly different from zero
Mean daily minimum
0.09 C (-0.01 to 0.18) per decade
0.15 F (-0.01 to 0.32) per decade
1899 to 1966
37
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
1899 to 1967
Yearly extremes at Rock Hall: the record and the median year
Measure
Record
Year of the record
Median year
Years with a value
Hottest day (TXx)
40.0 C (104.0 F)
1930
36.1 C (97.0 F)
53
Coldest night (TNn)
-25.6 C (-14.1 F)
1899
-14.4 C (6.1 F)
53
Wettest day (Rx1day)
190.5 mm (7.5 in)
1928
64.3 mm (2.5 in)
53
Wettest five days (Rx5day)
233.7 mm (9.2 in)
1928
92.9 mm (3.7 in)
53
Longest dry spell (CDD)
36 days
1930
19 days
53
Hottest day (TXx)
The hottest day of the year at Rock Hall, 1899 to 1967. The record is 40.0 C (104.0 F) in 1930, marked on the chart; the median year is 36.1 C (97.0 F).
Hottest day (TXx) at Rock Hall by year
Year
Hottest day (TXx)
1899
35.0 C (95.0 F)
1900
38.3 C (100.9 F)
1901
38.9 C (102.0 F)
1902
15.6 C (60.1 F)
1919
33.3 C (91.9 F)
1920
33.3 C (91.9 F)
1921
35.6 C (96.1 F)
1922
34.4 C (93.9 F)
1923
36.1 C (97.0 F)
1924
37.2 C (99.0 F)
1925
38.3 C (100.9 F)
1926
37.8 C (100.0 F)
1927
36.7 C (98.1 F)
1928
36.1 C (97.0 F)
1929
36.7 C (98.1 F)
1930
40.0 C (104.0 F)
1931
37.2 C (99.0 F)
1932
38.9 C (102.0 F)
1933
36.7 C (98.1 F)
1934
38.3 C (100.9 F)
1935
37.2 C (99.0 F)
1936
40.0 C (104.0 F)
1937
35.6 C (96.1 F)
1938
35.0 C (95.0 F)
1939
34.4 C (93.9 F)
1940
22.8 C (73.0 F)
1941
37.2 C (99.0 F)
1942
37.2 C (99.0 F)
1943
36.7 C (98.1 F)
1944
36.1 C (97.0 F)
1945
36.7 C (98.1 F)
1946
35.0 C (95.0 F)
1947
36.1 C (97.0 F)
1948
36.7 C (98.1 F)
1949
36.1 C (97.0 F)
1950
33.9 C (93.0 F)
1951
33.9 C (93.0 F)
1952
36.7 C (98.1 F)
1953
38.3 C (100.9 F)
1954
37.2 C (99.0 F)
1955
36.7 C (98.1 F)
1956
34.4 C (93.9 F)
1957
37.8 C (100.0 F)
1958
33.3 C (91.9 F)
1959
37.8 C (100.0 F)
1960
34.4 C (93.9 F)
1961
34.4 C (93.9 F)
1962
34.4 C (93.9 F)
1963
33.9 C (93.0 F)
1964
35.0 C (95.0 F)
1965
35.0 C (95.0 F)
1966
36.1 C (97.0 F)
1967
23.9 C (75.0 F)
Coldest night (TNn)
The coldest night of the year at Rock Hall, 1899 to 1967. The record is -25.6 C (-14.1 F) in 1899, marked on the chart; the median year is -14.4 C (6.1 F).
Coldest night (TNn) at Rock Hall by year
Year
Coldest night (TNn)
1899
-25.6 C (-14.1 F)
1900
-15.0 C (5.0 F)
1901
-13.3 C (8.1 F)
1902
-16.7 C (1.9 F)
1919
-16.7 C (1.9 F)
1920
-13.9 C (7.0 F)
1921
-11.1 C (12.0 F)
1922
-15.0 C (5.0 F)
1923
-11.7 C (10.9 F)
1924
-13.3 C (8.1 F)
1925
-16.1 C (3.0 F)
1926
-14.4 C (6.1 F)
1927
-14.4 C (6.1 F)
1928
-12.8 C (9.0 F)
1929
-12.8 C (9.0 F)
1930
-16.7 C (1.9 F)
1931
-11.7 C (10.9 F)
1932
-15.6 C (3.9 F)
1933
-15.0 C (5.0 F)
1934
-24.4 C (-11.9 F)
1935
-15.6 C (3.9 F)
1936
-17.8 C (0.0 F)
1937
-10.6 C (12.9 F)
1938
-11.7 C (10.9 F)
1939
-13.9 C (7.0 F)
1940
-18.9 C (-2.0 F)
1941
0.0 C (32.0 F)
1942
-15.6 C (3.9 F)
1943
-13.9 C (7.0 F)
1944
-11.7 C (10.9 F)
1945
-14.4 C (6.1 F)
1946
-14.4 C (6.1 F)
1947
-13.3 C (8.1 F)
1948
-12.2 C (10.0 F)
1949
-11.7 C (10.9 F)
1950
-12.2 C (10.0 F)
1951
-11.7 C (10.9 F)
1952
-10.0 C (14.0 F)
1953
-8.9 C (16.0 F)
1954
-13.9 C (7.0 F)
1955
-15.0 C (5.0 F)
1956
-12.2 C (10.0 F)
1957
-20.6 C (-5.1 F)
1958
-15.6 C (3.9 F)
1959
-15.0 C (5.0 F)
1960
-11.1 C (12.0 F)
1961
-2.8 C (27.0 F)
1962
-15.0 C (5.0 F)
1963
-16.1 C (3.0 F)
1964
-15.0 C (5.0 F)
1965
-16.1 C (3.0 F)
1966
-13.3 C (8.1 F)
1967
-15.0 C (5.0 F)
Wettest day (Rx1day)
The wettest day of the year at Rock Hall, 1899 to 1967. The record is 190.5 mm (7.5 in) in 1928, marked on the chart; the median year is 64.3 mm (2.5 in).
Wettest day (Rx1day) at Rock Hall by year
Year
Wettest day (Rx1day)
1899
61.0 mm (2.4 in)
1900
76.2 mm (3.0 in)
1901
75.4 mm (3.0 in)
1902
43.4 mm (1.7 in)
1919
33.0 mm (1.3 in)
1920
71.1 mm (2.8 in)
1921
51.3 mm (2.0 in)
1922
58.4 mm (2.3 in)
1923
45.7 mm (1.8 in)
1924
66.0 mm (2.6 in)
1925
79.8 mm (3.1 in)
1926
69.9 mm (2.8 in)
1927
41.9 mm (1.6 in)
1928
190.5 mm (7.5 in)
1929
85.9 mm (3.4 in)
1930
49.8 mm (2.0 in)
1931
112.3 mm (4.4 in)
1932
55.9 mm (2.2 in)
1933
101.6 mm (4.0 in)
1934
75.7 mm (3.0 in)
1935
88.9 mm (3.5 in)
1936
57.2 mm (2.3 in)
1937
50.8 mm (2.0 in)
1938
73.7 mm (2.9 in)
1939
83.8 mm (3.3 in)
1940
58.4 mm (2.3 in)
1941
45.7 mm (1.8 in)
1942
64.8 mm (2.6 in)
1943
50.3 mm (2.0 in)
1944
72.4 mm (2.9 in)
1945
77.5 mm (3.1 in)
1946
59.7 mm (2.4 in)
1947
49.3 mm (1.9 in)
1948
64.3 mm (2.5 in)
1949
71.6 mm (2.8 in)
1950
74.9 mm (2.9 in)
1951
51.3 mm (2.0 in)
1952
66.0 mm (2.6 in)
1953
102.6 mm (4.0 in)
1954
34.0 mm (1.3 in)
1955
85.9 mm (3.4 in)
1956
75.7 mm (3.0 in)
1957
37.3 mm (1.5 in)
1958
64.0 mm (2.5 in)
1959
55.9 mm (2.2 in)
1960
107.7 mm (4.2 in)
1961
43.9 mm (1.7 in)
1962
49.5 mm (1.9 in)
1963
55.4 mm (2.2 in)
1964
68.3 mm (2.7 in)
1965
41.9 mm (1.6 in)
1966
86.4 mm (3.4 in)
1967
42.4 mm (1.7 in)
Wettest five days (Rx5day)
The wettest five days of the year at Rock Hall, 1899 to 1967. The record is 233.7 mm (9.2 in) in 1928, marked on the chart; the median year is 92.9 mm (3.7 in).
Wettest five days (Rx5day) at Rock Hall by year
Year
Wettest five days (Rx5day)
1899
76.0 mm (3.0 in)
1900
115.6 mm (4.6 in)
1901
93.5 mm (3.7 in)
1902
74.2 mm (2.9 in)
1919
53.3 mm (2.1 in)
1920
76.2 mm (3.0 in)
1921
53.3 mm (2.1 in)
1922
78.4 mm (3.1 in)
1923
67.5 mm (2.7 in)
1924
92.9 mm (3.7 in)
1925
91.2 mm (3.6 in)
1926
132.5 mm (5.2 in)
1927
53.9 mm (2.1 in)
1928
233.7 mm (9.2 in)
1929
97.9 mm (3.9 in)
1930
56.2 mm (2.2 in)
1931
131.1 mm (5.2 in)
1932
81.2 mm (3.2 in)
1933
182.1 mm (7.2 in)
1934
106.6 mm (4.2 in)
1935
180.1 mm (7.1 in)
1936
90.4 mm (3.6 in)
1937
108.9 mm (4.3 in)
1938
126.2 mm (5.0 in)
1939
106.5 mm (4.2 in)
1940
78.7 mm (3.1 in)
1941
66.0 mm (2.6 in)
1942
143.7 mm (5.7 in)
1943
80.3 mm (3.2 in)
1944
90.9 mm (3.6 in)
1945
137.7 mm (5.4 in)
1946
106.7 mm (4.2 in)
1947
69.1 mm (2.7 in)
1948
105.7 mm (4.2 in)
1949
97.3 mm (3.8 in)
1950
156.2 mm (6.1 in)
1951
113.3 mm (4.5 in)
1952
132.4 mm (5.2 in)
1953
102.6 mm (4.0 in)
1954
61.5 mm (2.4 in)
1955
158.3 mm (6.2 in)
1956
77.2 mm (3.0 in)
1957
56.4 mm (2.2 in)
1958
89.2 mm (3.5 in)
1959
128.6 mm (5.1 in)
1960
149.9 mm (5.9 in)
1961
60.8 mm (2.4 in)
1962
67.6 mm (2.7 in)
1963
74.4 mm (2.9 in)
1964
115.8 mm (4.6 in)
1965
56.1 mm (2.2 in)
1966
104.7 mm (4.1 in)
1967
56.3 mm (2.2 in)
Longest dry spell (CDD)
The longest dry spell of the year at Rock Hall, 1899 to 1967. The record is 36 days in 1930, marked on the chart; the median year is 19 days.
Longest dry spell (CDD) at Rock Hall by year
Year
Longest dry spell (CDD)
1899
16 days
1900
20 days
1901
23 days
1902
18 days
1919
12 days
1920
10 days
1921
11 days
1922
24 days
1923
20 days
1924
27 days
1925
13 days
1926
18 days
1927
13 days
1928
12 days
1929
19 days
1930
36 days
1931
19 days
1932
16 days
1933
15 days
1934
19 days
1935
14 days
1936
22 days
1937
14 days
1938
16 days
1939
19 days
1940
13 days
1941
34 days
1942
26 days
1943
16 days
1944
19 days
1945
21 days
1946
25 days
1947
21 days
1948
20 days
1949
19 days
1950
16 days
1951
14 days
1952
22 days
1953
19 days
1954
13 days
1955
18 days
1956
15 days
1957
20 days
1958
20 days
1959
27 days
1960
20 days
1961
16 days
1962
16 days
1963
16 days
1964
29 days
1965
18 days
1966
32 days
1967
10 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
37 years with a frost
Across 37 years with a frost, the median last spring frost at Rock Hall falls on 15 April and the median first autumn frost on 24 October, which leaves a median of 192 days between them.
Fitted over all years, the growing season changes by -0.8 days per decade at this station.
Frost dates and growing season at Rock Hall
Measure
Median, all years
Earliest period
Recent period (1926 to 1966)
Recent against earliest
Fitted trend
Last spring frost
15 April
n/a
16 April
n/a
+0.8 days per decade
First autumn frost
24 October
n/a
27 October
n/a
0.0 days per decade
Growing days
192 days
n/a
192 days
n/a
-0.8 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
41 years, 1899 to 1966
A day with at least 65.8 mm (2.6 in) of rain is expected about once in 2 years. A day with at least 152.1 mm (6.0 in) of rain is expected about once in 100 years.
Rainfall return levels at Rock Hall: the daily rain expected about once in a given number of years
Expected about once in
A day with at least
Note
2 years
65.8 mm (2.6 in)
5 years
86.6 mm (3.4 in)
10 years
101.3 mm (4.0 in)
25 years
120.9 mm (4.8 in)
50 years
136.2 mm (5.4 in)
Longer than the 41 years of record
100 years
152.1 mm (6.0 in)
Longer than the 41 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, 41 years of values from 1899 to 1966.
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: 190.5 mm (7.5 in) in 1928; 112.3 mm (4.4 in) in 1931; 102.6 mm (4.0 in) in 1953.
Download the Data
Data for Rock Hall standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Rock Hall 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.