KMDT/KCXY · Temperature

Temperature Analysis

Diurnal cycles, seasonal offsets, cross-era validation · Hover any element
Peak TMIN Warm Bias
+0.9°F
July MDT overnight — both eras
TMAX Sign Reversal
Jun
Early +0.67°F → Modern -0.33°F
TMIN CI Overlap
9/12
Warm season signal robust
MK TMAX
p=0.000
Decreasing — do not fix offset
River Thermal
May-Oct
MDT warmer overnight confirmed
Diurnal Temperature Cycle — MDT vs CXY (tab for season)
TMAX Offset MDT-CXY — Early vs Modern with 95% CI
TMIN Offset MDT-CXY — Early vs Modern with 95% CI
Annual TMAX+TMIN Offset Series — Both Eras

Key Findings

01
TMIN warm-season signal is robust across both eras — MDT runs 0.7-1.1°F warmer overnight from May through October. The Susquehanna River stores summer heat and releases it nocturnally, keeping MDT warmer than upland CXY.
02
TMAX shows a complete sign reversal between eras — MDT was warmer in summer in 1948-65 (+0.67°F June) but is consistently cooler in 2001-25 (-0.33°F June). Instrumentation era artifact, not a physical change between sites.
03
The diurnal cycle confirms the valley signature. MDT and CXY converge near solar noon (strong mixing) then diverge at night — warmer at MDT in summer from river heat storage, colder in winter from cold air drainage into the floodplain.
04
For homogenization: Warm-season TMIN (May-Oct) is reliable. TMAX and winter TMIN are instrumentation-era dependent. Apply era-specific factors only and flag winter months as uncertain.