Good questions.
Real answers.

Weather apps tell you what's happening outside — temperature, rainfall, cloud cover. Open Window Today tells you what to do about it. We run that data through 32 home-specific logic models, each with its own thresholds for Yes, No or Wait. You get decisions, not data dumps.

A regular app might say "22°C, 78% humidity, partly cloudy." We say "Don't hang laundry out — humidity above 75% will leave clothes damp and musty."

Genuinely free. All 32 cards, every feature, no sign-in, no ads, no paywall. We're funded by optional coffee donations from people who find it useful.

There is no catch. We believe useful tools shouldn't cost money or attention.

No. Just type your city and get results instantly. We will never ask for your details to show you the laundry card. Saved locations are stored locally in your browser — nothing goes to our servers.

Yes. We use global OpenWeatherMap data covering every city and suburb worldwide. Type any location in any language and get live results. Logic checks are tuned to work across all climates — we don't assume you're in any particular region.

The interface is available in English, Spanish, French, German, Portuguese, Hindi, Arabic, Japanese and Chinese. Use the language buttons in the footer to switch. Your preference is remembered between visits.

We use OpenWeatherMap, which aggregates data from thousands of meteorological stations, satellites, weather balloons and models worldwide. We pull three data feeds simultaneously: current conditions, air quality (PM2.5), and a 48-hour forecast in 3-hour intervals.

Data is fetched fresh every time you search. We cache results for up to 10 minutes to avoid hammering the API — which also matches the frequency at which OpenWeatherMap updates its free-tier data. If you leave the page open, it auto-refreshes every 10 minutes. The 48-hour forecast strip updates with every search.

We measure PM2.5 particulate matter (fine particles under 2.5 microns) and translate them into the US EPA AQI scale (0–500):

0–50: Good — air is clean
51–100: Moderate — acceptable for most
101–150: Unhealthy for sensitive groups
151+: Unhealthy — avoid prolonged outdoor exposure

We show it as Good / Moderate / Unhealthy rather than raw numbers, so it's always instantly clear.

The OpenWeatherMap free tier doesn't include a direct UV index. We estimate UV using the current hour, cloud cover percentage, and season. It's a reasonable approximation but not a medically precise reading. For critical UV decisions (e.g. photosensitive conditions), treat it as directional rather than definitive.

We don't have access to real-time pollen count sensors (these are expensive and sparse). Instead we derive a risk score from conditions strongly correlated with high pollen: temperature above 12°C, humidity below 75%, low or no rain, and light wind. This captures the majority of high-pollen days but isn't a substitute for local pollen monitoring services during severe allergy season.

The forecast comes from OpenWeatherMap's global model in 3-hour slots. Accuracy degrades naturally the further out you go — the first 12–18 hours are reliable, 24–48 hours should be treated as directional. The check verdicts in forecast slots also estimate air quality at 50 (Good/Moderate) since AQ forecast data isn't available on the free tier.

Five conditions must all pass for a Yes: air quality below AQI 100, humidity at or below 80%, temperature between 15–30°C, no rain, no snow. If any single condition fails, you get a No with the specific reason. A Wait means conditions are borderline — open briefly but keep an eye on it.

Barometric pressure drops are a clinically documented migraine trigger. We compare the current pressure reading against the 3-hour forecast and flag drops greater than 5 hPa — the threshold most commonly associated with migraine onset in published research. We also flag high or very high pollen, which can trigger inflammatory responses linked to head pain.

For everyday sun protection decisions (SPF before a beach day, whether to reapply), yes. For medical decisions — such as photosensitive skin conditions or post-surgery care — please use a dedicated UV index service with real sensor data and consult your doctor.

Sunshine is just one factor. High humidity (above ~65%) means clothes won't dry properly even on bright days, because the air is already saturated with moisture. Laundry needs both low humidity and adequate airflow, not just sunshine.

No. Location data is sent directly to OpenWeatherMap to fetch weather and returned to your browser. We don't log it, store it, or associate it with any profile. Saved cities live in your browser's localStorage — they never touch our servers.

We use Google Analytics (GA4) to understand aggregate usage — page views, geography, device type. This is anonymised and doesn't identify you personally. We don't use advertising cookies or sell data to third parties. See our Privacy Policy for the full picture.

Use the 📍 pin to save up to 5 locations. They're stored using your browser's localStorage — entirely on your device. Clearing your browser data will remove them. Nothing is stored server-side. You can save home, work, a family member's address, holiday destination — whatever helps you most.