Lewistown Montana Climate Data

Monthly Average Climate Data for Lewistown Montana

Switch Data to Celsius/Metric Units
MonthAvg. LowAvg. HighAvg. Precip
January13.9 °F34.7 °F0.59 in.
February14.3 °F35.6 °F0.63 in.
March21.6 °F44.3 °F0.8 in.
April29.8 °F53.0 °F1.77 in.
May38.2 °F62.1 °F2.33 in.
June46.5 °F72.4 °F3.34 in.
July51.9 °F81.1 °F1.74 in.
August50.6 °F81.0 °F1.5 in.
September42.1 °F70.6 °F1.3 in.
October31.7 °F56.5 °F1.15 in.
November22.0 °F44.0 °F0.68 in.
December14.5 °F35.4 °F0.54 in.
Annual31.4 °F55.9 °F16.37 in.

Climate Data for Lewistown Montana

Average First Frost DateSep. 21 - Sep. 30
Average Last Frost DateMay 21 - May 31
Average Days With FrostOver 180 Days
Plant Hardiness Zone - 2023Zone 4b : -25°F to -20°F
Plant Hardiness Zone - 2012Zone 4a : -30°F to -25°F
Current Drought ConditionsAbnormally Dry
Köppen Climate ClassificationDfb - Humid Continental Mild Summer, Wet All Year
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