HELENA AIRPORT ASOS, MT

Total of Snowfall (Inches)

(244055)

File last updated on October 22, 2019
a = 1 day missing, b = 2 days missing, c = 3 days, ..etc..,
z = 26 or more days missing, A = Accumulations present
Long-term means based on columns; thus, the monthly row may not
sum (or average) to the long-term annual value.
MAXIMUM ALLOWABLE NUMBER OF MISSING DAYS : 5
Individual Months not used for annual or monthly statistics if more than 5 days are missing.
Individual Years not used for annual statistics if any month in that year has more than 5 days missing.

YEAR(S)JULAUGSEPOCTNOVDECJANFEBMARAPRMAYJUNANN
1937-38-----z-----z-----z-----z-----z-----z-----z-----z-----z-----z-----z-----z0.00l
1938-39-----z-----z-----z-----z-----z-----z-----z-----z-----z-----z0.00 0.00 0.00j
1939-400.00 0.00 -----z-----z0.00 0.00j-----z-----z-----z-----z0.00 0.00 0.00g
1940-410.00 0.00 0.00 0.00 8.30 0.50 4.80 1.30 2.00 3.10 0.00 0.00 20.00
1941-420.00 0.00 1.90 0.50 1.90 14.60 10.60 11.80 7.50 0.80 2.50 0.00 52.10
1942-430.00 0.00 0.10 0.00 11.50 3.10 24.60 8.00 9.20 2.30 0.00 0.00 58.80
1943-440.00 0.00 0.00 0.00 3.00 3.20 0.60 12.70 9.70 0.00 0.00 0.00 29.20
1944-450.00 0.00 0.00 0.00 3.30 12.40 3.30 1.30 2.50 3.70 0.00 0.00 26.50
1945-460.00 0.00 1.20 0.00 2.50 9.00 4.10 4.00 1.30 0.00 0.00 0.00 22.10
1946-470.00 0.00 0.00 4.30 14.50 12.50 4.60 3.60 7.00 1.30 0.00 0.00 47.80
1947-480.00 0.00 5.30 0.40 13.40 2.80 5.20 4.00 7.30 2.00 3.20 0.00 43.60
1948-490.00 0.00 0.00 0.50 1.60 13.20 13.80 11.20 12.10 0.00 0.60 0.00 53.00
1949-500.00 0.00 7.50 3.60 0.00 9.30 12.90 2.70 9.20 8.50 8.40 1.50 63.60
1950-510.00 0.00 0.90 0.20 19.90 9.90 5.80 2.90 11.40 3.50 4.40 0.90 59.80
1951-520.00 0.00 0.40 5.60 4.10 22.60 3.70 8.10 11.80 0.10 0.00 0.00 56.40
1952-530.00 0.00 0.00 0.00 13.60 4.30 3.20 14.50 1.40 0.60 0.40 0.00 38.00
1953-540.00 0.00 0.00 0.00 0.00 4.60 24.20 0.20 8.90 8.90 0.00 0.00 46.80
1954-550.00 0.00 1.60 1.30 9.70 0.30 3.40 3.30 21.60 10.90 2.20 0.00 54.30
1955-560.00 0.00 1.20 3.00 17.70 15.30 9.40 1.90 5.50 4.70 3.30 0.00 62.00
1956-570.00 0.00 0.00 1.90 0.70 5.40 18.70 5.80 12.90 6.30 0.00 0.00 51.70
1957-580.00 0.00 13.40 8.20 10.30 2.80 1.00 16.40 8.60 3.40 0.00 0.00 64.10
1958-590.00 0.00 0.00 0.30 7.40 15.30 7.40 19.70 0.40 1.50 0.00 0.00 52.00
1959-600.00 0.00 0.00 3.40 32.90 4.50 4.90 3.70 4.50 20.00 0.00 0.00 73.90
1960-610.00 0.00 0.00 4.10 2.00 2.90 1.80 0.40 9.10 8.30 0.00 0.00 28.60
1961-620.00 0.00 0.00 1.30 6.40 4.20 10.10 7.30 7.30 8.70 0.00 0.00 45.30
1962-630.00 0.00 0.40 0.00 1.20 1.50 9.80 2.00 5.90 2.30 0.00 0.00 23.10
1963-640.00 0.00 0.00 0.00 2.70 21.20 6.20 6.30 7.40 6.60 10.10 0.00 60.50
1964-650.00 0.00 0.00 0.00 6.30 13.20 2.30 9.40 12.90 6.30 5.00 0.00 55.40
1965-660.00 0.00 13.70 0.00 2.10 1.40 6.30 5.10 2.30 1.90 0.00 0.00 32.80
1966-670.00 0.00 0.00 0.00 9.50 5.70 7.30 10.50 14.90 20.60 12.70 0.00 81.20
1967-680.00 0.00 0.00 0.00 2.70 22.80 8.70 0.90 0.80 10.00 0.00 0.00 45.90
1968-690.00 0.00 3.00 0.40 7.40 11.00 35.60 3.60 7.00 2.60 0.70 2.70 74.00
1969-700.00 0.00 0.00 11.00 0.10 6.10 7.00 9.50 9.00 7.90 1.40 0.00 52.00
1970-710.00 0.00 0.00 1.40 5.40 7.50 16.20 3.50 2.50 0.70 0.00 0.00 37.20
1971-720.00 0.00 0.00 0.80 4.60 14.50 14.90 3.30 4.50 3.80 0.00 0.00 46.40
1972-730.00 0.00 0.30 4.70 0.70 7.80 3.20 1.80 0.10 6.50 0.00 0.00 25.10
1973-740.00 0.00 1.30 7.20 12.50 7.20 9.90 5.90 2.20 1.50 0.20 0.00 47.90
1974-750.00 0.00 0.00 1.50 0.80 2.70 15.20 10.70 12.30 15.40 0.20 0.00 58.80
1975-760.00 0.00 0.00 6.30 4.90 3.90 3.30 4.40 6.70 10.90 0.00 0.00 40.40
1976-770.00 0.00 0.00 0.00 2.90 0.90 13.80 0.80 14.10 0.50 1.00 0.00 34.00
1977-780.00 0.00 0.00 0.40 6.80 19.50 15.70 13.30 2.60 0.90 0.00 0.00 59.20
1978-790.00 0.00 0.00 0.00 22.10 13.80 11.70 7.20 12.40 9.30 0.00 0.00 76.50
1979-800.00 0.00 0.00 0.20 0.60 6.50 9.30 10.50 10.10 3.10 0.00 0.00 40.30
1980-810.00 0.00 0.00 3.70 1.20 3.80 2.70 2.10 3.30 0.10 0.00 0.00 16.90
1981-820.00 0.00 0.00 5.20 3.40 6.10 18.40 4.80 13.90 4.10 0.80 0.00 56.70
1982-830.00 0.00 6.50 0.50 4.10 11.30 3.20 0.20 2.20 1.10 9.90 0.00 39.00
1983-840.00 0.00 6.40 0.00 1.30 13.00 1.30 1.50 5.70 2.30 0.80 0.00 32.30
1984-850.00 0.00 6.30 9.00 5.70 7.50 3.90 6.20 4.00 0.80 0.00 0.00 43.40
1985-860.00 0.00 2.90 8.80 10.40 8.50 4.20 15.60 1.20 11.60 0.20 0.00 63.40
1986-870.00 0.00 0.00 0.00 7.60 5.00 0.20 0.20 9.10 4.30 3.80 0.00 30.20
1987-880.00 0.00 0.00 0.30 0.90 1.20 4.40 8.00 5.20 2.90 0.00 0.00 22.90
1988-890.00 0.00 5.90 1.50 6.00 5.00 23.00 13.00 20.70 7.90 3.50 0.00 86.50
1989-900.00 0.00 0.00 2.60 1.80 9.40 4.30 1.80 14.00 0.80 0.10 0.00 34.80
1990-910.00 0.00 0.00 0.50 8.60 11.60 5.90 0.80 12.20 5.60 0.40 0.50 46.10
1991-920.00 0.00 0.00 7.30 8.80 15.70 4.70 1.30 0.00 2.20 0.00 0.00 40.00
1992-930.00 6.20 0.00 8.60 1.50 11.80 10.20 17.90 2.30 2.50 0.00 0.00 61.00
1993-940.00 0.00 0.00 4.60 7.30 1.10 4.40 5.00 4.40 8.00 0.00 0.00 34.80
1994-950.00 0.00 0.00 0.00 8.60 2.00 0.30 1.60 8.10 7.10 0.90 0.00 28.60
1995-960.00 0.00 0.00 0.00 2.40 2.70 14.20 -----z-----z-----z-----z-----z19.30e
1996-970.00 0.00 0.00 0.00a2.30e10.20a-----z-----z-----z-----z-----z-----z12.50f
1997-98-----z-----z-----z-----z-----z-----z-----z-----z-----z-----z-----z-----z0.00l
1998-99-----z-----z-----z-----z-----z-----z2.00i2.90h0.00c4.70e2.20 0.00 6.90h
1999-000.00 0.00 0.00 0.00 0.00b0.50d3.90 5.70 2.30 -----z-----z0.00t12.40c
2000-01-----z-----z-----z-----z0.00x-----z-----z-----z-----z-----z-----z-----z0.00l
2001-02-----z-----z-----z-----z-----z-----z-----z-----z-----z-----z-----z-----z0.00l
2002-03-----z-----z-----z-----z-----z-----z-----z-----z-----z-----z-----z-----z0.00l
2003-04-----z-----z-----z-----z-----z-----z-----z-----z0.00o4.80 0.00 0.00 4.80i
2004-050.00 0.00 0.00 0.00 1.30 6.70 11.20 0.40 10.90 0.00 0.00 0.00 30.50
2005-060.00 0.00 0.00 0.00 3.90 6.50 1.20 0.90 6.60 0.20 0.00 0.00 19.30
2006-070.00 0.00 0.00 1.20 6.10 0.40 1.70 8.80 0.30 0.30 0.00 0.00 18.80
2007-080.00 0.00 0.00 0.00 3.80 0.00 12.70 6.80 1.00 7.00 0.00 0.00 31.30
2008-090.00 0.00 0.00 1.20 0.20 15.90 5.70 4.70 8.30 5.70 0.00 0.20 41.90
2009-100.00 0.00 0.00 3.70 1.20 10.40 9.40 1.30 0.10 1.60 0.20 0.00 27.90
2010-110.00 0.00 0.00 0.00 9.40 8.20 2.20 12.60 1.00 3.00 0.00 0.00 36.40
2011-120.00 0.00 0.00 0.00 12.00 0.90 15.70 10.10 1.40 0.00 0.00 0.00 40.10
2012-130.00 0.00 0.00 0.00 17.00 7.10 5.30 6.30 0.40 3.60 0.00 0.00 39.70
2013-140.00 0.00 0.00 2.00 1.50 1.20a6.70a26.50a3.40a0.00 0.00 0.00 41.30
2014-150.00 0.00 0.00a0.00 10.80b-----z7.40 1.70 0.00 0.00 0.00 0.00 19.90a
2015-160.00 0.00 0.00 0.00 3.50 7.60 3.70 0.30 0.00 0.00 0.00 0.00 15.10
2016-170.00 0.00 0.00 1.00 0.30 23.80 12.70 10.80 2.90 0.00 0.00 0.00 51.50
2017-180.00 0.00 0.00 1.30 7.50 23.20 3.40 12.50 10.70 6.10 0.00 0.00 64.70
2018-190.00 0.00 0.00 0.40 2.00 2.00 8.50 26.80 9.20 0.60 0.00 0.00 49.50
2019-200.00 0.00 3.20 2.50j-----z-----z-----z-----z-----z-----z-----z-----z3.20i
Period of Record Statistics
MEAN0.00 0.08 1.13 1.86 5.95 8.06 8.21 6.62 6.44 4.28 1.07 0.08 44.71
S.D.0.00 0.72 2.76 2.75 5.99 6.23 6.63 5.95 5.08 4.46 2.52 0.37 16.32
SKEW0.00 8.49 3.07 1.60 1.83 0.83 1.56 1.34 0.67 1.59 3.03 5.69 0.31
MAX0.00 6.20 13.70 11.00 32.90 23.80 35.60 26.80 21.60 20.60 12.70 2.70 86.50
MIN0.00 0.00 0.00 0.00 0.00 0.00 0.20 0.20 0.00 0.00 0.00 0.00 15.10
YRS75 75 74 73 74 72 72 71 72 72 74 74 69