Though located along the Blue Ridge Mountains at elevations exceeding 900 ft , with four distinct, but generally mild, seasons; it is located in USDA hardiness zone 7b, with the suburbs falling in zone 7a. Extremes in temperature have ranged from 105 °F (41 °C) as recently as August 21, 1983, down to −12 °F (−24 °C) on December 30, 1917, though neither 100 °F (38 °C) nor 0 °F (−18 °C) is reached in most years; the most recent occurrence of each is July 8, 2012 and February 20, 2015. More typically, the area records an average of 7.7 days where the temperature stays at or below freezing and 25 days with 90 °F (32 °C)+ highs annually. The normal monthly mean temperature ranges from 36.6 °F (2.6 °C) in January to 76.7 °F (24.8 °C) in July.
Based on the 1981−2010 period, the city averages 16.6 inches (42 cm) of snow per winter. Roanoke experienced something of a snow drought in the 2000s until December 2009 when 17 inches (43 cm) of snow fell on Roanoke in a single storm. Winter snowfall has ranged from trace amounts in 1918–19 and 1919–20 to 62.7 inches (159 cm) in 1959–60; unofficially, the largest single storm dumped approximately three feet (0.9 m) from December 16−18, 1890.
Flooding is the primary weather-related hazard faced by Roanoke. Heavy rains, most frequently from remnants of a hurricane, drain from surrounding areas to the narrow Roanoke Valley. The most recent significant flood was in the fall of 2004, caused by the remains of Hurricane Ivan. The most severe flooding in the city’s history occurred on November 4, 1985, when heavy storms from the remnants of Hurricane Juan stalled over the area. Ten people drowned in the Roanoke Valley and others were saved by rescue personnel.
Many residents complain that they are prone to allergies because of pollen from trees in the surrounding mountains. Most famously, the family of Wayne Newton moved from Roanoke to the dry climate of Phoenix, Arizona, because of his childhood asthma and allergies. However, there have not been clinical studies to establish that these conditions are more prevalent in Roanoke than in other cities with similar vegetation and climate.