Leonardtown 4 SSW Weather Records (USC00185200)

Record envelope, standing records and threshold days for Leonardtown 4 SSW (USC00185200), Maryland, United States, with 67 years of record.

Key Facts for Leonardtown 4 SSW

Leonardtown 4 SSW (USC00185200) is a weather station in Maryland, United States at 38.25 latitude and -76.65 longitude, 6 m (20 ft) above sea level.
The station reports from 1893 to 1959, 67 years of record.
1,464 records set at Leonardtown 4 SSW still stand.
Records are tracked for no element yet: an element needs 30 years of data to be eligible.

About the Station

Location: Maryland, United States, 38.25 latitude, -76.65 longitude.
Elevation: 6 m (20 ft).
Period of record: 1893 to 1959, 67 years.
Eligible elements: none yet.

Daily Record Envelope and 2026

0 days at or beyond a record

The band shows the record high and record low for each calendar day at Leonardtown 4 SSW. 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 Leonardtown 4 SSW, with 2026 drawn through them
Month	Highest record high	Lowest record low	2026 highest maximum	2026 lowest minimum
Jan	25.6 C (78.1 F)	-22.2 C (-8.0 F)	n/a	n/a
Feb	23.3 C (73.9 F)	-16.7 C (1.9 F)	n/a	n/a
Mar	27.8 C (82.0 F)	-12.8 C (9.0 F)	n/a	n/a
Apr	35.6 C (96.1 F)	-4.4 C (24.1 F)	n/a	n/a
May	36.1 C (97.0 F)	0.0 C (32.0 F)	n/a	n/a
Jun	37.8 C (100.0 F)	6.1 C (43.0 F)	n/a	n/a
Jul	41.1 C (106.0 F)	10.0 C (50.0 F)	n/a	n/a
Aug	37.8 C (100.0 F)	8.9 C (48.0 F)	n/a	n/a
Sep	36.7 C (98.1 F)	2.8 C (37.0 F)	n/a	n/a
Oct	35.0 C (95.0 F)	-4.4 C (24.1 F)	n/a	n/a
Nov	28.9 C (84.0 F)	-8.9 C (16.0 F)	n/a	n/a
Dec	23.3 C (73.9 F)	-19.4 C (-2.9 F)	n/a	n/a

Which Years Hold Standing Records

1,464 standing records

1,464 records at Leonardtown 4 SSW still stand. 1940 holds the most, with 106.

Standing records at Leonardtown 4 SSW by the year they were set
Year set	Standing records
1893	57
1911	79
1912	71
1913	81
1914	98
1915	72
1916	33
1917	56
1939	65
1940	106
1941	61
1942	35
1948	39
1949	54
1950	74
1951	54
1952	55
1953	55
1954	64
1955	48
1956	59
1957	58
1958	47
1959	43

Wettest Day of Each Month

Aug: 109.5 mm (4.3 in)

The wettest day on record for each calendar month at Leonardtown 4 SSW. The most was 109.5 mm (4.3 in) on 12 August 1955.

Record daily precipitation for each month at Leonardtown 4 SSW
Month	Record daily precipitation (mm)	Date
Jan	43.2 mm (1.7 in)	22 January 1954
Feb	31.5 mm (1.2 in)	11 February 1893
Mar	76.2 mm (3.0 in)	15 March 1912
Apr	49.0 mm (1.9 in)	15 April 1893
May	65.3 mm (2.6 in)	3 May 1893
Jun	85.1 mm (3.4 in)	13 June 1941
Jul	107.2 mm (4.2 in)	15 July 1959
Aug	109.5 mm (4.3 in)	12 August 1955
Sep	58.7 mm (2.3 in)	24 September 1912
Oct	86.4 mm (3.4 in)	1 October 1915
Nov	68.1 mm (2.7 in)	21 November 1952
Dec	62.7 mm (2.5 in)	13 December 1941

Period of Record Coverage

1893 to 1959

24 years of record at Leonardtown 4 SSW, 1893 to 1959. 8 years have data for under 90 percent of days and are left out of rankings: 1893, 1911, 1916, 1917, 1939, 1942, 1948, 1959.

Days with data per year at Leonardtown 4 SSW
Year	Days with data	Share of year	Complete
1893	209	57%	No
1911	316	87%	No
1912	362	99%	Yes
1913	363	99%	Yes
1914	362	99%	Yes
1915	357	98%	Yes
1916	224	61%	No
1917	321	88%	No
1939	275	75%	No
1940	364	99%	Yes
1941	365	100%	Yes
1942	181	50%	No
1948	183	50%	No
1949	364	100%	Yes
1950	359	98%	Yes
1951	365	100%	Yes
1952	366	100%	Yes
1953	364	100%	Yes
1954	356	98%	Yes
1955	365	100%	Yes
1956	365	100%	Yes
1957	364	100%	Yes
1958	362	99%	Yes
1959	232	64%	No

Latest Records

No records were set at this station in the latest data.

Climate Trend

16 complete years, 1912 to 1958

One stripe for each of 16 complete years at Leonardtown 4 SSW, 1912 to 1958. Blue stripes are years cooler than the station's own mean of 13.9 C (57.0 F); red stripes are warmer. The coolest year was 1940, at 12.5 C (54.5 F), and the warmest was 1949, at 15.1 C (59.3 F). The strongest colour marks a difference of 1.5 C (2.7 F).

Annual mean temperature at Leonardtown 4 SSW as warming stripes, 1912 to 1958
Year	Annual mean temperature	Difference from the station mean
1912	13.2 C	-0.67 C
1913	14.4 C	+0.52 C
1914	13.3 C	-0.65 C
1915	13.5 C	-0.43 C
1940	12.5 C	-1.41 C
1941	14.2 C	+0.27 C
1949	15.1 C	+1.23 C
1950	14.2 C	+0.26 C
1951	14.1 C	+0.20 C
1952	14.0 C	+0.10 C
1953	14.5 C	+0.59 C
1954	14.4 C	+0.45 C
1955	14.0 C	+0.11 C
1956	13.9 C	-0.01 C
1957	14.3 C	+0.41 C
1958	12.9 C	-1.04 C

This station does not have enough complete years (30 are needed) to fit a temperature trend.

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

1893 to 1959

Yearly extremes at Leonardtown 4 SSW: the record and the median year
Measure	Record	Year of the record	Median year	Years with a value
Hottest day (TXx)	41.1 C (106.0 F)	1911	37.0 C (98.5 F)	24
Coldest night (TNn)	-22.2 C (-8.0 F)	1957	-12.5 C (9.5 F)	24
Wettest day (Rx1day)	109.5 mm (4.3 in)	1955	71.3 mm (2.8 in)	24
Wettest five days (Rx5day)	238.4 mm (9.4 in)	1948	99.2 mm (3.9 in)	24
Longest dry spell (CDD)	35 days	1941	19 days	24

Hottest day (TXx)

The hottest day of the year at Leonardtown 4 SSW, 1893 to 1959. The record is 41.1 C (106.0 F) in 1911, marked on the chart; the median year is 37.0 C (98.5 F).

Hottest day (TXx) at Leonardtown 4 SSW by year
Year	Hottest day (TXx)
1893	35.0 C (95.0 F)
1911	41.1 C (106.0 F)
1912	34.4 C (93.9 F)
1913	37.8 C (100.0 F)
1914	37.8 C (100.0 F)
1915	36.7 C (98.1 F)
1916	33.9 C (93.0 F)
1917	35.6 C (96.1 F)
1939	35.6 C (96.1 F)
1940	37.8 C (100.0 F)
1941	37.2 C (99.0 F)
1942	36.1 C (97.0 F)
1948	36.7 C (98.1 F)
1949	36.1 C (97.0 F)
1950	36.1 C (97.0 F)
1951	36.1 C (97.0 F)
1952	37.2 C (99.0 F)
1953	37.2 C (99.0 F)
1954	38.3 C (100.9 F)
1955	37.2 C (99.0 F)
1956	37.2 C (99.0 F)
1957	37.8 C (100.0 F)
1958	34.4 C (93.9 F)
1959	37.8 C (100.0 F)

Coldest night (TNn)

The coldest night of the year at Leonardtown 4 SSW, 1893 to 1959. The record is -22.2 C (-8.0 F) in 1957, marked on the chart; the median year is -12.5 C (9.5 F).

Coldest night (TNn) at Leonardtown 4 SSW by year
Year	Coldest night (TNn)
1893	-19.4 C (-2.9 F)
1911	-8.9 C (16.0 F)
1912	-21.1 C (-6.0 F)
1913	-10.6 C (12.9 F)
1914	-16.1 C (3.0 F)
1915	-7.8 C (18.0 F)
1916	-13.9 C (7.0 F)
1917	-16.7 C (1.9 F)
1939	-7.2 C (19.0 F)
1940	-20.0 C (-4.0 F)
1941	-9.4 C (15.1 F)
1942	-20.0 C (-4.0 F)
1948	-11.7 C (10.9 F)
1949	-8.9 C (16.0 F)
1950	-10.6 C (12.9 F)
1951	-12.8 C (9.0 F)
1952	-10.6 C (12.9 F)
1953	-7.8 C (18.0 F)
1954	-12.2 C (10.0 F)
1955	-12.8 C (9.0 F)
1956	-9.4 C (15.1 F)
1957	-22.2 C (-8.0 F)
1958	-19.4 C (-2.9 F)
1959	-14.4 C (6.1 F)

Wettest day (Rx1day)

The wettest day of the year at Leonardtown 4 SSW, 1893 to 1959. The record is 109.5 mm (4.3 in) in 1955, marked on the chart; the median year is 71.3 mm (2.8 in).

Wettest day (Rx1day) at Leonardtown 4 SSW by year
Year	Wettest day (Rx1day)
1893	65.3 mm (2.6 in)
1911	74.2 mm (2.9 in)
1912	76.2 mm (3.0 in)
1913	41.9 mm (1.6 in)
1914	50.8 mm (2.0 in)
1915	86.4 mm (3.4 in)
1916	40.9 mm (1.6 in)
1917	78.2 mm (3.1 in)
1939	65.8 mm (2.6 in)
1940	78.5 mm (3.1 in)
1941	85.1 mm (3.4 in)
1942	50.3 mm (2.0 in)
1948	81.0 mm (3.2 in)
1949	84.1 mm (3.3 in)
1950	67.3 mm (2.6 in)
1951	58.4 mm (2.3 in)
1952	68.1 mm (2.7 in)
1953	68.3 mm (2.7 in)
1954	46.7 mm (1.8 in)
1955	109.5 mm (4.3 in)
1956	56.4 mm (2.2 in)
1957	82.6 mm (3.3 in)
1958	106.4 mm (4.2 in)
1959	107.2 mm (4.2 in)

Wettest five days (Rx5day)

The wettest five days of the year at Leonardtown 4 SSW, 1893 to 1959. The record is 238.4 mm (9.4 in) in 1948, marked on the chart; the median year is 99.2 mm (3.9 in).

Wettest five days (Rx5day) at Leonardtown 4 SSW by year
Year	Wettest five days (Rx5day)
1893	70.4 mm (2.8 in)
1911	113.8 mm (4.5 in)
1912	120.2 mm (4.7 in)
1913	54.3 mm (2.1 in)
1914	87.6 mm (3.4 in)
1915	104.4 mm (4.1 in)
1916	77.5 mm (3.1 in)
1917	79.5 mm (3.1 in)
1939	86.4 mm (3.4 in)
1940	98.7 mm (3.9 in)
1941	99.6 mm (3.9 in)
1942	58.2 mm (2.3 in)
1948	238.4 mm (9.4 in)
1949	146.8 mm (5.8 in)
1950	134.3 mm (5.3 in)
1951	78.6 mm (3.1 in)
1952	109.6 mm (4.3 in)
1953	87.6 mm (3.4 in)
1954	63.5 mm (2.5 in)
1955	237.2 mm (9.3 in)
1956	110.5 mm (4.4 in)
1957	82.6 mm (3.3 in)
1958	145.0 mm (5.7 in)
1959	147.0 mm (5.8 in)

Longest dry spell (CDD)

The longest dry spell of the year at Leonardtown 4 SSW, 1893 to 1959. The record is 35 days in 1941, marked on the chart; the median year is 19 days.

Longest dry spell (CDD) at Leonardtown 4 SSW by year
Year	Longest dry spell (CDD)
1893	20 days
1911	23 days
1912	16 days
1913	15 days
1914	21 days
1915	30 days
1916	18 days
1917	22 days
1939	16 days
1940	13 days
1941	35 days
1942	23 days
1948	15 days
1949	26 days
1950	17 days
1951	13 days
1952	23 days
1953	19 days
1954	24 days
1955	15 days
1956	20 days
1957	19 days
1958	12 days
1959	19 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.

Download the Data

Data for Leonardtown 4 SSW standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Leonardtown 4 SSW 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.

Data as of 2025-12-31. Last revised 31 December 2025 (2025-12-31).