Past Weather History: Eranorms

Yellowsquared

In-app purchases

About this app

Tired of opening a weather app and still not knowing whether today is unusual?

Eranorms is a weather almanac and historical climate companion for travelers, researchers, gardeners, and curious locals who want context instead of a bare forecast. Compare current conditions with decades of observations from local weather stations before you book a trip, move to a new city, or plant a garden.

GLOBAL COVERAGE
Explore past weather from 7,500+ stations across 200+ countries and territories. Many locations have 70+ years of history; coverage varies by station and weather variable. No forecasts—just decades of what actually happened.

DATA SOURCES
Historical station records from the Iowa Environmental Mesonet (IEM), with additional data from NOAA and ECMWF ERA5.

WEATHER ON THIS DATE
Pick any calendar day and see how it has behaved across 70+ years. The average temperature by date, the record high and record low, how often it rained or snowed, and where today sits inside that range. It is the difference between "it is 28 degrees" and "it is 28 degrees, which is 9 degrees above normal for this date."

WHAT ARE CLIMATE NORMALS?
A climate normal is the multi-decade average that meteorologists measure "above normal" and "below normal" against. Eranorms computes normals for temperature, rainfall, and snowfall at every station, so you can see the baseline instead of taking a forecast's word for it.

HOW IT WORKS
1. Pick a city or weather station.
2. Compare temperature, rainfall, and normals across decades.
3. Switch between box plots, climate stripes, heat maps, and seasonal charts.
4. Export charts and historical weather data for deeper analysis.

KEY FEATURES
- 70+ years of historical weather data from local stations
- Weather on this date: daily records, averages, and anomalies
- Climate normals for temperature, precipitation, and snowfall
- Average temperature by date, month, season, and year
- Record highs, record lows, and first and last frost dates
- City comparisons for travel and relocation planning
- Box plots and climate stripes for fast visual insight
- Rainfall, snowfall, and wind rose charts
- Seasonal trend and anomaly charts across decades
- ENSO context for El Nino and La Nina patterns
- Station maps and export-ready data views

WHO IT IS FOR
Travelers checking whether a destination is usually hot, wet, or windy in the month they are going. People relocating who want to know what a winter there actually looks like. Gardeners tracking frost dates and growing-season heat. Researchers, students, and journalists who need real station data instead of a summary. Anyone who has wondered whether this summer was genuinely hotter, or whether it only felt that way.

WHY IT IS DIFFERENT
Most weather apps answer "what is it doing right now." Eranorms answers "is that normal." Forecasts look days ahead; a weather almanac looks decades back, and that history is what tells you whether to pack a raincoat for a trip in April or whether to worry about a late frost.

Stop guessing local weather trends. Download Eranorms and see how today fits into history.

What’s new

Eranorms 4.0.0

• Redesigned Weather Recap with poster-style layouts and milestone historical indicators.
• New severe weather event tracking and drought monitoring.
• Interactive snapshot evidence charts for deep-dive climate metrics.
• Performance improvements and bug fixes for chart rendering.