How RouteWeather Works: Data Sources & Methodology

Last updated: August 2026. This page explains every data source, calculation, and logic rule behind RouteWeather's recommendations. It is regenerated automatically whenever underlying methodology changes.

What RouteWeather Does

RouteWeather is a travel decision intelligence tool. It computes the logistics, weather risk, and cost for driving a specific route — then surfaces an honest comparison of driving versus flying versus taking the train. The goal is to answer the question: "Given today's conditions, what is the safest and most cost-effective way to make this trip?"

RouteWeather is not a booking engine. It helps you decide before you book.

Data Sources

Source	What We Use It For	Refresh	Reliability
Open-Meteo + MET Norway fallback	Hourly model forecasts matched to estimated arrival time along the route. MET Norway is used only if the primary forecast service fails.	Per route request; cached briefly	Forecast guidance, not observed road conditions. Accuracy declines with time and local terrain.
OSRM (Open Source Routing Machine)	Route geometry, distance, and estimated driving time. A second OSRM endpoint is tried if the primary endpoint fails.	Per route request	Community road data. Not turn-by-turn navigation and not truck-restriction routing.
Photon + Nominatim fallback / OpenStreetMap	User-triggered location search and route-point labels. Nominatim is rate-limited and is not used for autocomplete.	Per request	High for city and address-level resolution. Occasional gaps in rural areas.
FuelEconomy.gov / U.S. Energy Information Administration	National regular-gasoline and diesel planning averages and exact EPA vehicle efficiency records.	Gasoline and diesel usually update weekly	Authoritative national average; explicitly not a station-specific pump price.
NREL, Open Charge Map, and OpenStreetMap	Candidate public EV charging locations near range-based charge windows, with a live map-search fallback.	Per EV route request; cached for six hours	Location records only. Connector, access, working status, and live stall availability must be verified.

Route Calculation Logic

When you enter an origin and destination, RouteWeather:

Geocodes the origin, destination, and optional stops with Photon, then tries Nominatim if the primary service is unavailable.
Requests up to three OSRM road-route alternatives and selects according to the user’s Fastest, Balanced, Scenic-ish, or Family priority.
Interpolates route waypoints at the selected interval and assigns an estimated arrival time to each point.
Matches hourly Open-Meteo forecasts to each ETA, with MET Norway as a failure fallback, then checks U.S. National Weather Service alerts.
Uses the selected vehicle profile or exact EPA vehicle record to estimate fuel or charging cost.
For EVs, estimates charge windows from range, starting charge, reserve, connector, and charging-speed preferences, then looks for candidate chargers.
Suggests break and overnight windows without inventing business inventory, prices, ratings, or availability.

Default: The Sedan profile starts at 32 MPG. Users can choose SUV, pickup, large truck, EV, or an exact FuelEconomy.gov vehicle and edit every energy assumption.

Weather Risk Classification

Each waypoint is given a severity label from forecast conditions, visibility, wind, precipitation, and snowfall thresholds:

Severity	Display	Definition
Clear	✅	No weather impact on route safety. Normal driving conditions.
Caution	⚠️	Precipitation, reduced visibility, or temperatures below 32°F. Slow down; allow extra stopping distance.
Hazard	🚨	Active snow, ice, thunderstorm, or freezing rain. Delay departure or consider alternatives.

Fuel Price & Cost Calculation

The default Sedan profile uses 32 MPG. SUV, pickup, large-truck, and EV profiles use different editable assumptions. When “weekly U.S. average” is selected, RouteWeather uses the regular-gasoline or diesel value published by FuelEconomy.gov from EIA data. This is a national planning baseline—not a current price for any station. RouteWeather never invents a station discount or “savings” percentage.

Formula: route miles ÷ selected MPG × selected fuel-price assumption. EV cost uses route miles × kWh/100 miles ÷ 100 × the public-charging price assumption.

Drive vs. Fly vs. Train Logic

RouteWeather shows the calculated driving baseline beside clearly labeled links that open current travel searches. It does not fabricate fares, schedules, inventory, or a “cheapest” winner. Weather risk remains visible so a lower commission or price can never override safety context.

Known Limitations

Station fuel prices: No reliable licensed free source provides live prices for every U.S. station. RouteWeather shows a weekly national average or the user’s own observed price and labels it honestly.
EV charging: Charge windows and times are estimates. Charger records do not guarantee connector compatibility, access, working status, pricing, or an open stall.
Large trucks: Costs can be estimated, but OSRM car routing does not verify height, weight, hazmat, or commercial-road restrictions.
Travel searches: Partner buttons open current searches. RouteWeather does not claim a fare, room, rental, coupon, or deal unless the linked provider supplies one.
Weather horizon: ETA-matched planning is limited to 16 days, and forecast confidence declines farther from departure.
Rural locations: Community geocoding and charger data can be incomplete in rural areas; verify critical stops independently.

Update Frequency

Data Type	Refresh Rate
Hourly weather (per waypoint)	Per route request; cached for about 15 minutes
Route geometry & drive time	Real-time on each route request (OSRM)
U.S. national fuel-price assumptions	Gasoline and diesel usually update weekly at the source
EV charging locations	Per EV route request; cached for about six hours
This methodology page	Updated whenever calculation logic changes

Affiliate & Referral Disclosure
Some clearly labeled links, currently including Expedia, are affiliate links. RouteWeather may earn a commission if you complete a purchase, at no added cost to you. Commission never changes route safety, weather, charging, or stop order. A link is labeled “Sponsored” beside the recommendation; unlabeled external search links are not presented as paid deals.