KMDT / KCXY · Wind Analysis · Harrisburg PA

Wind Rose Climatology

Directional frequency analysis · Early era 1949–1965 vs ASOS era 2001–2025
MDT: 40.1962°N 76.7725°W elev 91m (river floodplain) · CXY: 40.2171°N 76.8515°W elev 106m (upland) · 3.3mi separation
Early Era Obs
6,097
Daily WSFG readings 1949–1965
Modern Era Obs
9,124
Daily WDF2/WSF2 readings 2001–2025
Dominant Direction
NW
30.2% early · 35.9% modern
Biggest Shift
SE
10.3% → 18.4% (+8.1% modern)
Windiest Month
Apr
25.3 mph median gust (early)
MDT Early Era (1949–1965) · WSFG Peak Gust Direction
MDT Modern Era (2001–2025) · WDF2 Fastest 2-min Direction
CXY Modern Era (2001–2025) · WDF2 Fastest 2-min Direction
Direction Frequency Comparison (% of observations)

Key Findings

01
NW sector dominates both eras at MDT — 30.2% early, 35.9% modern. Post-frontal westerly flow channeled through the Susquehanna Valley is the consistent driver.
02
SE frequency nearly doubled in the modern era (+8.1%). This is the cold air damming signature — NE/SE low-level flow during CAD events along the Appalachian barrier.
03
Spring is windiest (Mar–Apr) in both eras. March median peak gust = 25.1 mph early; April = 25.3 mph. Consistent with strong frontal passages in spring.
04
Measurement caveat: Early WSFG = instantaneous peak gust. Modern WDF2 = fastest 2-minute average. Direction comparison is climatological only — speed not directly comparable.
05
CXY vs MDT modern: CXY records slightly higher SE frequency (19.2% vs 18.4%) — consistent with CXY's upland position being more exposed to valley channeling during CAD.
06
Summer months calmest in both eras. August median peak gust = 17.0 mph early; modern mean wind = 4.6 mph. Consistent with weakened pressure gradient in warm season.