Mercersburg 1 E Weather Records (USC00365662)
Record envelope, standing records and threshold days for Mercersburg 1 E (USC00365662), Pennsylvania, United States, with 63 years of record.
Key Facts for Mercersburg 1 E
- Mercersburg 1 E (USC00365662) is a weather station in Pennsylvania, United States at 39.83 latitude and -77.90 longitude, 165 m (541 ft) above sea level.
- The station reports from 1928 to 1990, 63 years of record.
- 1,464 records set at Mercersburg 1 E still stand.
- Records are tracked for tmax, tmin, prcp, snow, snwd: an element needs 30 years of data to be eligible.
- Mercersburg 1 E set a daily record high minimum temperature of 21.7 C (71.1 F) on 29 June 1990.
About the Station
- Location: Pennsylvania, United States, 39.83 latitude, -77.90 longitude.
- Elevation: 165 m (541 ft).
- Period of record: 1928 to 1990, 63 years.
- Eligible elements: tmax, tmin, prcp, snow, snwd.
Daily Record Envelope and 2026
0 days at or beyond a record| Month | Highest record high | Lowest record low | 2026 highest maximum | 2026 lowest minimum |
|---|---|---|---|---|
| Jan | 22.8 C (73.0 F) | -27.8 C (-18.0 F) | n/a | n/a |
| Feb | 27.8 C (82.0 F) | -24.4 C (-11.9 F) | n/a | n/a |
| Mar | 31.1 C (88.0 F) | -16.1 C (3.0 F) | n/a | n/a |
| Apr | 33.9 C (93.0 F) | -8.9 C (16.0 F) | n/a | n/a |
| May | 35.0 C (95.0 F) | -6.7 C (19.9 F) | n/a | n/a |
| Jun | 38.3 C (100.9 F) | 1.7 C (35.1 F) | n/a | n/a |
| Jul | 41.1 C (106.0 F) | 4.4 C (39.9 F) | n/a | n/a |
| Aug | 40.0 C (104.0 F) | 3.3 C (37.9 F) | n/a | n/a |
| Sep | 37.8 C (100.0 F) | -1.7 C (28.9 F) | n/a | n/a |
| Oct | 31.1 C (88.0 F) | -9.4 C (15.1 F) | n/a | n/a |
| Nov | 28.9 C (84.0 F) | -15.0 C (5.0 F) | n/a | n/a |
| Dec | 26.1 C (79.0 F) | -23.3 C (-9.9 F) | n/a | n/a |
Which Years Hold Standing Records
1,464 standing records| Year set | Standing records |
|---|---|
| 1960 | 49 |
| 1961 | 57 |
| 1962 | 41 |
| 1963 | 59 |
| 1964 | 59 |
| 1965 | 58 |
| 1966 | 62 |
| 1967 | 59 |
| 1968 | 52 |
| 1969 | 35 |
| 1970 | 38 |
| 1971 | 42 |
| 1972 | 54 |
| 1973 | 44 |
| 1974 | 44 |
| 1975 | 39 |
| 1976 | 56 |
| 1977 | 51 |
| 1978 | 32 |
| 1979 | 60 |
| 1980 | 40 |
| 1981 | 42 |
| 1982 | 54 |
| 1983 | 42 |
| 1984 | 44 |
| 1985 | 36 |
| 1986 | 51 |
| 1987 | 46 |
| 1988 | 66 |
| 1989 | 42 |
| 1990 | 10 |
Wettest Day of Each Month
Oct: 143.0 mm (5.6 in)| Month | Record daily precipitation (mm) | Date |
|---|---|---|
| Jan | 52.8 mm (2.1 in) | 6 January 1944 |
| Feb | 69.3 mm (2.7 in) | 13 February 1936 |
| Mar | 86.1 mm (3.4 in) | 17 March 1936 |
| Apr | 91.4 mm (3.6 in) | 15 April 1929 |
| May | 83.8 mm (3.3 in) | 23 May 1938 |
| Jun | 93.2 mm (3.7 in) | 22 June 1972 |
| Jul | 74.2 mm (2.9 in) | 3 July 1981 |
| Aug | 79.2 mm (3.1 in) | 23 August 1933 |
| Sep | 129.0 mm (5.1 in) | 6 September 1979 |
| Oct | 143.0 mm (5.6 in) | 17 October 1942 |
| Nov | 128.3 mm (5.1 in) | 30 November 1934 |
| Dec | 53.3 mm (2.1 in) | 4 December 1950 |
Period of Record Coverage
1960 to 1990| Year | Days with data | Share of year | Complete |
|---|---|---|---|
| 1960 | 365 | 100% | Yes |
| 1961 | 365 | 100% | Yes |
| 1962 | 365 | 100% | Yes |
| 1963 | 365 | 100% | Yes |
| 1964 | 366 | 100% | Yes |
| 1965 | 364 | 100% | Yes |
| 1966 | 364 | 100% | Yes |
| 1967 | 365 | 100% | Yes |
| 1968 | 366 | 100% | Yes |
| 1969 | 364 | 100% | Yes |
| 1970 | 362 | 99% | Yes |
| 1971 | 364 | 100% | Yes |
| 1972 | 366 | 100% | Yes |
| 1973 | 332 | 91% | Yes |
| 1974 | 348 | 95% | Yes |
| 1975 | 361 | 99% | Yes |
| 1976 | 366 | 100% | Yes |
| 1977 | 365 | 100% | Yes |
| 1978 | 365 | 100% | Yes |
| 1979 | 365 | 100% | Yes |
| 1980 | 361 | 99% | Yes |
| 1981 | 345 | 95% | Yes |
| 1982 | 355 | 97% | Yes |
| 1983 | 361 | 99% | Yes |
| 1984 | 359 | 98% | Yes |
| 1985 | 361 | 99% | Yes |
| 1986 | 351 | 96% | Yes |
| 1987 | 347 | 95% | Yes |
| 1988 | 349 | 95% | Yes |
| 1989 | 315 | 86% | No |
| 1990 | 58 | 16% | No |
Latest Records
20| Date | Station | Record | Value | Beat old record by | Old record stood | Significance |
|---|---|---|---|---|---|---|
| 29 June 1990 | Mercersburg 1 E, US | daily high min | 21.7 C (71.1 F) | 1.1 C (2.0 F) | 20 years | 11 of 100 (Routine) |
| 28 June 1990 | Mercersburg 1 E, US | daily high min | 21.1 C (70.0 F) | 1.7 C (3.1 F) | 27 years | 15 of 100 (Routine) |
| 19 June 1990 | Mercersburg 1 E, US | daily high min | 21.7 C (71.1 F) | 1.1 C (2.0 F) | 12 years | 8 of 100 (Routine) |
| 18 June 1990 | Mercersburg 1 E, US | daily high min | 20.6 C (69.1 F) | 2.3 C (4.1 F) | 23 years | 14 of 100 (Routine) |
| 17 June 1990 | Mercersburg 1 E, US | daily high min | 21.1 C (70.0 F) | 1.7 C (3.1 F) | 8 years | 9 of 100 (Routine) |
| 10 June 1990 | Mercersburg 1 E, US | daily high min | 21.1 C (70.0 F) | 0.5 C (0.9 F) | 16 years | 9 of 100 (Routine) |
| 9 June 1990 | Mercersburg 1 E, US | daily high min | 22.2 C (72.0 F) | 2.2 C (4.0 F) | 3 years | 8 of 100 (Routine) |
| 8 June 1990 | Mercersburg 1 E, US | daily high min (Tie) | 20.0 C (68.0 F) | tie | 4 years | 1 of 100 (Routine) |
| 5 June 1990 | Mercersburg 1 E, US | daily low min (Tie) | 5.6 C (42.1 F) | tie | 24 years | 2 of 100 (Routine) |
| 28 April 1990 | Mercersburg 1 E, US | daily high min (Tie) | 11.1 C (52.0 F) | tie | 20 years | 2 of 100 (Routine) |
| 27 April 1990 | Mercersburg 1 E, US | daily high max (Tie) | 31.7 C (89.1 F) | tie | 28 years | 2 of 100 (Routine) |
| 26 April 1990 | Mercersburg 1 E, US | daily high max | 32.8 C (91.0 F) | 1.1 C (2.0 F) | 29 years | 12 of 100 (Routine) |
| 25 April 1990 | Mercersburg 1 E, US | daily high max (Tie) | 31.7 C (89.1 F) | tie | 29 years | 2 of 100 (Routine) |
| 19 April 1990 | Mercersburg 1 E, US | daily low min | -5.6 C (21.9 F) | 1.7 C (3.1 F) | 7 years | 8 of 100 (Routine) |
| 13 April 1990 | Mercersburg 1 E, US | daily low min | -6.7 C (19.9 F) | 0.6 C (1.1 F) | 0 years | 4 of 100 (Routine) |
| 24 November 1989 | Mercersburg 1 E, US | daily snow depth | 2.5 cm (1.0 in) | 2.5 cm (1.0 in) | 40 years | 19 of 100 (Routine) |
| 23 November 1989 | Mercersburg 1 E, US | daily snowfall | 5.1 cm (2.0 in) | 5.1 cm (2.0 in) | 44 years | 29 of 100 (Routine) |
| 23 November 1989 | Mercersburg 1 E, US | daily snow depth | 5.1 cm (2.0 in) | 5.1 cm (2.0 in) | 40 years | 20 of 100 (Routine) |
| 16 November 1989 | Mercersburg 1 E, US | daily rain | 47.5 mm (1.9 in) | 19.6 mm (0.8 in) | 4 years | 21 of 100 (Routine) |
| 31 July 1989 | Mercersburg 1 E, US | daily rain | 48.3 mm (1.9 in) | 10.7 mm (0.4 in) | 18 years | 19 of 100 (Routine) |
Climate Trend
27 complete years, 1960 to 1988| Year | Annual mean temperature | Difference from the station mean |
|---|---|---|
| 1960 | 10.4 C | -0.10 C |
| 1961 | 11.0 C | +0.47 C |
| 1962 | 10.4 C | -0.11 C |
| 1963 | 10.2 C | -0.31 C |
| 1964 | 10.8 C | +0.32 C |
| 1965 | 11.0 C | +0.46 C |
| 1966 | 10.7 C | +0.22 C |
| 1967 | 10.3 C | -0.27 C |
| 1968 | 10.9 C | +0.35 C |
| 1969 | 10.9 C | +0.33 C |
| 1970 | 11.1 C | +0.59 C |
| 1971 | 10.7 C | +0.22 C |
| 1972 | 10.6 C | +0.09 C |
| 1975 | 10.5 C | -0.04 C |
| 1976 | 9.9 C | -0.65 C |
| 1977 | 10.7 C | +0.14 C |
| 1978 | 9.8 C | -0.69 C |
| 1979 | 9.7 C | -0.80 C |
| 1980 | 10.5 C | -0.01 C |
| 1981 | 9.5 C | -1.00 C |
| 1982 | 10.1 C | -0.42 C |
| 1983 | 10.4 C | -0.17 C |
| 1984 | 10.7 C | +0.22 C |
| 1985 | 11.0 C | +0.51 C |
| 1986 | 10.7 C | +0.22 C |
| 1987 | 11.1 C | +0.59 C |
| 1988 | 10.4 C | -0.14 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
1928 to 1990| Measure | Record | Year of the record | Median year | Years with a value |
|---|---|---|---|---|
| Hottest day (TXx) | 41.1 C (106.0 F) | 1988 | 35.6 C (96.1 F) | 31 |
| Coldest night (TNn) | -27.8 C (-18.0 F) | 1982 | -19.4 C (-2.9 F) | 31 |
| Wettest day (Rx1day) | 143.0 mm (5.6 in) | 1942 | 61.0 mm (2.4 in) | 63 |
| Wettest five days (Rx5day) | 198.3 mm (7.8 in) | 1972 | 84.6 mm (3.3 in) | 60 |
| Longest dry spell (CDD) | 32 days | 1963 | 17 days | 62 |
Hottest day (TXx)
| Year | Hottest day (TXx) |
|---|---|
| 1928 | n/a |
| 1929 | n/a |
| 1930 | n/a |
| 1931 | n/a |
| 1932 | n/a |
| 1933 | n/a |
| 1934 | n/a |
| 1935 | n/a |
| 1936 | n/a |
| 1937 | n/a |
| 1938 | n/a |
| 1939 | n/a |
| 1940 | n/a |
| 1941 | n/a |
| 1942 | n/a |
| 1943 | n/a |
| 1944 | n/a |
| 1945 | n/a |
| 1946 | n/a |
| 1947 | n/a |
| 1948 | n/a |
| 1949 | n/a |
| 1950 | n/a |
| 1951 | n/a |
| 1952 | n/a |
| 1953 | n/a |
| 1954 | n/a |
| 1955 | n/a |
| 1956 | n/a |
| 1957 | n/a |
| 1958 | n/a |
| 1959 | n/a |
| 1960 | 33.9 C (93.0 F) |
| 1961 | 35.6 C (96.1 F) |
| 1962 | 38.9 C (102.0 F) |
| 1963 | 35.6 C (96.1 F) |
| 1964 | 36.1 C (97.0 F) |
| 1965 | 36.1 C (97.0 F) |
| 1966 | 38.9 C (102.0 F) |
| 1967 | 34.4 C (93.9 F) |
| 1968 | 36.7 C (98.1 F) |
| 1969 | 37.8 C (100.0 F) |
| 1970 | 35.0 C (95.0 F) |
| 1971 | 34.4 C (93.9 F) |
| 1972 | 35.6 C (96.1 F) |
| 1973 | 35.6 C (96.1 F) |
| 1974 | 32.2 C (90.0 F) |
| 1975 | 36.7 C (98.1 F) |
| 1976 | 34.4 C (93.9 F) |
| 1977 | 38.9 C (102.0 F) |
| 1978 | 35.6 C (96.1 F) |
| 1979 | 34.4 C (93.9 F) |
| 1980 | 37.8 C (100.0 F) |
| 1981 | 35.6 C (96.1 F) |
| 1982 | 35.6 C (96.1 F) |
| 1983 | 40.0 C (104.0 F) |
| 1984 | 35.0 C (95.0 F) |
| 1985 | 35.6 C (96.1 F) |
| 1986 | 37.2 C (99.0 F) |
| 1987 | 38.9 C (102.0 F) |
| 1988 | 41.1 C (106.0 F) |
| 1989 | 35.6 C (96.1 F) |
| 1990 | 35.0 C (95.0 F) |
Coldest night (TNn)
| Year | Coldest night (TNn) |
|---|---|
| 1928 | n/a |
| 1929 | n/a |
| 1930 | n/a |
| 1931 | n/a |
| 1932 | n/a |
| 1933 | n/a |
| 1934 | n/a |
| 1935 | n/a |
| 1936 | n/a |
| 1937 | n/a |
| 1938 | n/a |
| 1939 | n/a |
| 1940 | n/a |
| 1941 | n/a |
| 1942 | n/a |
| 1943 | n/a |
| 1944 | n/a |
| 1945 | n/a |
| 1946 | n/a |
| 1947 | n/a |
| 1948 | n/a |
| 1949 | n/a |
| 1950 | n/a |
| 1951 | n/a |
| 1952 | n/a |
| 1953 | n/a |
| 1954 | n/a |
| 1955 | n/a |
| 1956 | n/a |
| 1957 | n/a |
| 1958 | n/a |
| 1959 | n/a |
| 1960 | -23.3 C (-9.9 F) |
| 1961 | -20.6 C (-5.1 F) |
| 1962 | -18.3 C (-0.9 F) |
| 1963 | -23.9 C (-11.0 F) |
| 1964 | -18.9 C (-2.0 F) |
| 1965 | -18.3 C (-0.9 F) |
| 1966 | -16.7 C (1.9 F) |
| 1967 | -21.1 C (-6.0 F) |
| 1968 | -24.4 C (-11.9 F) |
| 1969 | -16.1 C (3.0 F) |
| 1970 | -17.2 C (1.0 F) |
| 1971 | -16.1 C (3.0 F) |
| 1972 | -18.9 C (-2.0 F) |
| 1973 | -15.6 C (3.9 F) |
| 1974 | -16.1 C (3.0 F) |
| 1975 | -16.7 C (1.9 F) |
| 1976 | -19.4 C (-2.9 F) |
| 1977 | -24.4 C (-11.9 F) |
| 1978 | -23.9 C (-11.0 F) |
| 1979 | -24.4 C (-11.9 F) |
| 1980 | -17.8 C (0.0 F) |
| 1981 | -22.2 C (-8.0 F) |
| 1982 | -27.8 C (-18.0 F) |
| 1983 | -23.3 C (-9.9 F) |
| 1984 | -24.4 C (-11.9 F) |
| 1985 | -26.7 C (-16.1 F) |
| 1986 | -15.6 C (3.9 F) |
| 1987 | -25.0 C (-13.0 F) |
| 1988 | -23.3 C (-9.9 F) |
| 1989 | -15.6 C (3.9 F) |
| 1990 | -6.7 C (19.9 F) |
Wettest day (Rx1day)
| Year | Wettest day (Rx1day) |
|---|---|
| 1928 | 45.7 mm (1.8 in) |
| 1929 | 128.8 mm (5.1 in) |
| 1930 | 40.6 mm (1.6 in) |
| 1931 | 50.8 mm (2.0 in) |
| 1932 | 78.7 mm (3.1 in) |
| 1933 | 79.2 mm (3.1 in) |
| 1934 | 128.3 mm (5.1 in) |
| 1935 | 49.8 mm (2.0 in) |
| 1936 | 88.1 mm (3.5 in) |
| 1937 | 85.1 mm (3.4 in) |
| 1938 | 83.8 mm (3.3 in) |
| 1939 | 71.1 mm (2.8 in) |
| 1940 | 66.0 mm (2.6 in) |
| 1941 | 69.3 mm (2.7 in) |
| 1942 | 143.0 mm (5.6 in) |
| 1943 | 83.8 mm (3.3 in) |
| 1944 | 52.8 mm (2.1 in) |
| 1945 | 76.2 mm (3.0 in) |
| 1946 | 62.0 mm (2.4 in) |
| 1947 | 47.2 mm (1.9 in) |
| 1948 | 49.5 mm (1.9 in) |
| 1949 | 39.9 mm (1.6 in) |
| 1950 | 67.6 mm (2.7 in) |
| 1951 | 50.0 mm (2.0 in) |
| 1952 | 90.9 mm (3.6 in) |
| 1953 | 57.7 mm (2.3 in) |
| 1954 | 80.0 mm (3.1 in) |
| 1955 | 66.0 mm (2.6 in) |
| 1956 | 67.3 mm (2.6 in) |
| 1957 | 42.7 mm (1.7 in) |
| 1958 | 61.0 mm (2.4 in) |
| 1959 | 50.0 mm (2.0 in) |
| 1960 | 68.6 mm (2.7 in) |
| 1961 | 44.5 mm (1.8 in) |
| 1962 | 49.3 mm (1.9 in) |
| 1963 | 45.0 mm (1.8 in) |
| 1964 | 57.4 mm (2.3 in) |
| 1965 | 78.7 mm (3.1 in) |
| 1966 | 54.6 mm (2.1 in) |
| 1967 | 64.0 mm (2.5 in) |
| 1968 | 46.0 mm (1.8 in) |
| 1969 | 46.7 mm (1.8 in) |
| 1970 | 53.1 mm (2.1 in) |
| 1971 | 70.4 mm (2.8 in) |
| 1972 | 93.2 mm (3.7 in) |
| 1973 | 65.5 mm (2.6 in) |
| 1974 | 73.2 mm (2.9 in) |
| 1975 | 64.0 mm (2.5 in) |
| 1976 | 101.6 mm (4.0 in) |
| 1977 | 37.6 mm (1.5 in) |
| 1978 | 47.5 mm (1.9 in) |
| 1979 | 129.0 mm (5.1 in) |
| 1980 | 47.0 mm (1.9 in) |
| 1981 | 74.2 mm (2.9 in) |
| 1982 | 36.8 mm (1.4 in) |
| 1983 | 50.8 mm (2.0 in) |
| 1984 | 78.7 mm (3.1 in) |
| 1985 | 59.7 mm (2.4 in) |
| 1986 | 45.0 mm (1.8 in) |
| 1987 | 53.3 mm (2.1 in) |
| 1988 | 56.9 mm (2.2 in) |
| 1989 | 60.5 mm (2.4 in) |
| 1990 | 29.2 mm (1.1 in) |
Wettest five days (Rx5day)
| Year | Wettest five days (Rx5day) |
|---|---|
| 1928 | n/a |
| 1929 | 28.5 mm (1.1 in) |
| 1930 | 47.0 mm (1.9 in) |
| 1931 | 55.7 mm (2.2 in) |
| 1932 | 91.5 mm (3.6 in) |
| 1933 | 103.5 mm (4.1 in) |
| 1934 | 59.5 mm (2.3 in) |
| 1935 | 54.7 mm (2.2 in) |
| 1936 | 107.2 mm (4.2 in) |
| 1937 | 87.6 mm (3.4 in) |
| 1938 | 52.3 mm (2.1 in) |
| 1939 | 74.6 mm (2.9 in) |
| 1940 | n/a |
| 1941 | n/a |
| 1942 | 143.0 mm (5.6 in) |
| 1943 | 83.8 mm (3.3 in) |
| 1944 | 72.4 mm (2.9 in) |
| 1945 | 114.6 mm (4.5 in) |
| 1946 | 62.5 mm (2.5 in) |
| 1947 | 85.6 mm (3.4 in) |
| 1948 | 64.5 mm (2.5 in) |
| 1949 | 54.1 mm (2.1 in) |
| 1950 | 98.0 mm (3.9 in) |
| 1951 | 111.2 mm (4.4 in) |
| 1952 | 154.6 mm (6.1 in) |
| 1953 | 64.6 mm (2.5 in) |
| 1954 | 87.6 mm (3.4 in) |
| 1955 | 102.6 mm (4.0 in) |
| 1956 | 78.7 mm (3.1 in) |
| 1957 | 64.0 mm (2.5 in) |
| 1958 | 106.6 mm (4.2 in) |
| 1959 | 80.5 mm (3.2 in) |
| 1960 | 83.7 mm (3.3 in) |
| 1961 | 83.6 mm (3.3 in) |
| 1962 | 67.1 mm (2.6 in) |
| 1963 | 70.7 mm (2.8 in) |
| 1964 | 64.3 mm (2.5 in) |
| 1965 | 92.4 mm (3.6 in) |
| 1966 | 78.2 mm (3.1 in) |
| 1967 | 95.2 mm (3.7 in) |
| 1968 | 71.6 mm (2.8 in) |
| 1969 | 73.2 mm (2.9 in) |
| 1970 | 85.4 mm (3.4 in) |
| 1971 | 94.8 mm (3.7 in) |
| 1972 | 198.3 mm (7.8 in) |
| 1973 | 108.4 mm (4.3 in) |
| 1974 | 101.4 mm (4.0 in) |
| 1975 | 179.0 mm (7.0 in) |
| 1976 | 124.8 mm (4.9 in) |
| 1977 | 74.2 mm (2.9 in) |
| 1978 | 112.0 mm (4.4 in) |
| 1979 | 139.2 mm (5.5 in) |
| 1980 | 69.9 mm (2.8 in) |
| 1981 | 108.5 mm (4.3 in) |
| 1982 | 73.1 mm (2.9 in) |
| 1983 | 75.0 mm (3.0 in) |
| 1984 | 176.5 mm (6.9 in) |
| 1985 | 99.0 mm (3.9 in) |
| 1986 | 75.5 mm (3.0 in) |
| 1987 | 131.3 mm (5.2 in) |
| 1988 | 127.5 mm (5.0 in) |
| 1989 | 99.9 mm (3.9 in) |
| 1990 | 30.5 mm (1.2 in) |
Longest dry spell (CDD)
| Year | Longest dry spell (CDD) |
|---|---|
| 1928 | 1 day |
| 1929 | 14 days |
| 1930 | 20 days |
| 1931 | 28 days |
| 1932 | 20 days |
| 1933 | 13 days |
| 1934 | 17 days |
| 1935 | 28 days |
| 1936 | 25 days |
| 1937 | 22 days |
| 1938 | 17 days |
| 1939 | 17 days |
| 1940 | 1 day |
| 1941 | n/a |
| 1942 | 15 days |
| 1943 | 19 days |
| 1944 | 16 days |
| 1945 | 14 days |
| 1946 | 21 days |
| 1947 | 24 days |
| 1948 | 16 days |
| 1949 | 15 days |
| 1950 | 15 days |
| 1951 | 22 days |
| 1952 | 29 days |
| 1953 | 19 days |
| 1954 | 14 days |
| 1955 | 27 days |
| 1956 | 16 days |
| 1957 | 20 days |
| 1958 | 25 days |
| 1959 | 14 days |
| 1960 | 21 days |
| 1961 | 15 days |
| 1962 | 16 days |
| 1963 | 32 days |
| 1964 | 26 days |
| 1965 | 18 days |
| 1966 | 15 days |
| 1967 | 12 days |
| 1968 | 26 days |
| 1969 | 17 days |
| 1970 | 16 days |
| 1971 | 22 days |
| 1972 | 15 days |
| 1973 | 22 days |
| 1974 | 18 days |
| 1975 | 15 days |
| 1976 | 24 days |
| 1977 | 17 days |
| 1978 | 16 days |
| 1979 | 17 days |
| 1980 | 13 days |
| 1981 | 16 days |
| 1982 | 16 days |
| 1983 | 17 days |
| 1984 | 11 days |
| 1985 | 27 days |
| 1986 | 20 days |
| 1987 | 22 days |
| 1988 | 29 days |
| 1989 | 16 days |
| 1990 | 14 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
27 years with a frostAcross 27 years with a frost, the median last spring frost at Mercersburg 1 E falls on 2 May and the median first autumn frost on 6 October, which leaves a median of 159 days between them.
Fitted over all years, the growing season changes by -7.0 days per decade at this station.
| Measure | Median, all years | Earliest period | Recent period (1960 to 1988) | Recent against earliest | Fitted trend |
|---|---|---|---|---|---|
| Last spring frost | 2 May | n/a | 2 May | n/a | +0.3 days per decade |
| First autumn frost | 6 October | n/a | 6 October | n/a | -6.7 days per decade |
| Growing days | 159 days | n/a | 159 days | n/a | -7.0 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
45 years, 1937 to 1989A day with at least 57.5 mm (2.3 in) of rain is expected about once in 2 years. A day with at least 128.5 mm (5.1 in) of rain is expected about once in 100 years.
| Expected about once in | A day with at least | Note |
|---|---|---|
| 2 years | 57.5 mm (2.3 in) | |
| 5 years | 73.5 mm (2.9 in) | |
| 10 years | 85.2 mm (3.4 in) | |
| 25 years | 101.3 mm (4.0 in) | |
| 50 years | 114.5 mm (4.5 in) | Longer than the 45 years of record |
| 100 years | 128.5 mm (5.1 in) | Longer than the 45 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, 45 years of values from 1937 to 1989.
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: 129.0 mm (5.1 in) in 1979; 101.6 mm (4.0 in) in 1976; 93.2 mm (3.7 in) in 1972.
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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 2026-10-17 (17 October 2026). Records are computed by this site and are not official.
Data as of . Last revised (2025-12-31).