Indianapolis, the capital of Indiana, sits on the White River on the flat till plains of central Indiana at approximately 39.77°N, 86.16°W. It has a humid continental climate (Köppen Dfa) — with hot, humid summers and cold winters — and four sharply distinct seasons, with precipitation spread through the year.

Summer, from June to August, is hot and humid, with July the warmest month — average highs around 30°C — and heatwaves that can exceed 35°C, made muggy by Gulf moisture drawn north. It is the wettest season, with frequent afternoon thunderstorms, some severe enough to produce damaging hail or tornadoes across the open farmland.

Winter, from December to February, is cold and grey, with January the coldest month — average highs around 3°C and lows near -7°C, with cold snaps below -18°C. Snow falls, around 65 cm a year, though thaws are frequent, and the flat, open landscape offers no shelter from the biting winds.

Indianapolis receives around 1,050–1,100 mm of precipitation a year, spread through every month with a spring and summer maximum from thunderstorms; spring is the peak severe-weather season across the Ohio valley. Live rainfall, humidity, and pressure readings for the city are shown in the panels above.

Indianapolis sits on the flat plains where Canadian and Gulf air masses collide, making spring its most volatile season: severe thunderstorms, damaging hail and tornadoes strike the surrounding farmland most often in April and May, at the northern edge of the country's tornado corridor.

To follow any single measurement in Indianapolis more closely, use our live instruments: the online barometer for atmospheric pressure, the thermometer for temperature, the hygrometer for humidity, the anemometer for wind speed, the wind vane for wind direction, and the rain gauge for rainfall.