Weather & Nature Tools
Check the weather forecast for any city, or get a just-for-fun risk estimate for roaches and jellyfish based on live local conditions.
Find the moon's phase and illumination for any date, computed from real lunar astronomy rather than a lookup table.
Sunrise & Sunset CalculatorSunrise, sunset, golden hour and twilight times for any place and date, computed from your coordinates rather than a nearby city.
Tide Chart ViewerLive 7-day tide predictions for thousands of US NOAA stations, with a nearest-station finder and tide curve — and what predictions cannot include.
Snake IdentifierIdentify common North American snakes by region, pattern, colour and size — with a clear venomous flag and a plain warning about relying on identification.
Star WatcherIdentify stars, planets, constellations, meteor showers and deep-sky objects for any date, ranked for your sky and kit, with cloud and rain.
Weather CheckerCheck the current weather, an hourly forecast and a five-day outlook for any city — with what forecast accuracy actually looks like.
Roach Risk TrackerEstimate cockroach activity risk for a location from temperature, humidity and season — and what actually works if you have them.
Jellyfish WatchEstimate jellyfish risk at a coastal spot from water temperature, waves and season — plus what the evidence actually says about treating a sting.
Sky TonightWhat is visible tonight from your location — planets, the Moon, bright stars and passes — computed from real positions rather than a generic list.
Telescope Back Spacing CalculatorHit the back focus your corrector wants — with the filter shift, the real factor at your spacing, and a plate-solve calibration when the spec is unclear.
Adiabatic Lapse Rate CalculatorHow fast lifted air cools — the dry rate is gravity over heat capacity, which is why the pilot rule of 3 C per 1000 ft is the physics rounded.
Cloud Base Height CalculatorCloud base from the temperature and dewpoint — and why the famous 125 metres per degree is a subtraction of two lapse rates.
Lightning Distance CalculatorHow far the strike was, from the count and the air temperature — because five seconds to the mile is right in the cold and 7% out in the warm.
About these weather & nature tools
A thirty per cent chance of rain does not mean rain over thirty per cent of the area, or for thirty per cent of the day. Probability of precipitation is the forecaster’s confidence multiplied by the fraction of the forecast area expected to get wet, and it refers to at least a hundredth of an inch falling at any given point. Thirty per cent can mean complete certainty that scattered showers will cover thirty per cent of the region, or thirty per cent confidence in a system that would soak all of it, and the forecast reads identically either way. That is why the number feels unreliable — people check it against the wrong question. The second thing worth knowing is that thunder gives you a free rangefinder. Sound covers a mile in about five seconds, so counting from flash to thunder and dividing by five gives the distance in miles. The useful threshold is thirty: if the gap is under thirty seconds the storm is within about six miles and already close enough to strike, and the standard advice is to wait thirty minutes after the last thunder before going back out, because the trailing edge of a storm produces strikes well clear of any rain. The third is that wind chill and heat index are not temperatures. They are models of how exposed skin loses or fails to lose heat, built on assumptions about wind height, body shape and shade, and they describe an average adult rather than you. Wind chill in particular says nothing about how fast a car engine or a water pipe cools — those reach the actual air temperature and no lower, however hard the wind blows.