ChescoWx · Chester County PA · An ongoing series

ChescoWx Studies

What makes Chester County's climate unique

Each study takes one question about Chester County weather, tests it against our station records, and gives an answer with the numbers behind it. We compare stations over the same years so that era does not get mixed in with elevation or equipment, and we say where the data runs thin. New studies are added as they are finished, and existing ones are updated as new data comes in.

Climate patterns & cyclesDeep analysis of how the County's terrain, location and long-term record shape its temperature, frost, rain and snow.
Equipment & toolsThe weather monitoring instruments and how they are sited, and what that does to the readings.
Past stormsWrite-ups and details on notable Chester County storms, built from our station and observer reports.
Published studies

The series so far

02
ClimatePublished Oct 5, 2026 · Updated Oct 8, 2026

Elevation & Terrain: Do the Hills Really Run Colder?

Valley floors vs. hilltops across the Chester County Area, compared over the same years, for temperature, frost, snow and rain.

  • Daytime highs drop about 1.7°F for every 300 ft, but nights run backwards: cold air drains into the valleys, so the hills stay milder and get a growing season about 3 weeks longer.
  • The hills get about 8% more snow per 300 ft from the same storm, and closer to 18% in marginal March and April storms.
  • Rainfall shows no elevation effect at all.
Read the study →
01
EquipmentPublished Sep 27, 2026

Equipment & Siting: How Much Do They Affect Accuracy?

Three weather stations side by side in East Nantmeal: a fan-aspirated Davis at ground level, a rooftop Tempest and a ground-level Ambient with a passive shield.

  • The rooftop station ran about 3°F warm on sunny summer afternoons and logged 45 days of 90°F vs. 8 at ground level.
  • The passive shield at ground level matched the fan-aspirated station within a few tenths, so the warm bias comes from the roof, not the shield.
  • Once that shield was damaged it ran almost 7°F warm on sunny days. Location first, then upkeep.
Read the study →

More studies are on the way. Questions or suggestions for a future study are always welcome.