Het weer in Pittsburgh in september

Pittsburgh's forum calls September, alongside October, the nicest stretch of the year — mid-70s to 80s by day, cool enough for a light sweater by evening. Regulars still note the odd genuinely hot day can turn up even this late in summer, so packing only for mild weather is a mistake.

Regulars are candid this month resists easy prediction, warning visitors to be ready for rain, snow, and unexpected warm, sunny days all as real possibilities - snow as early as October has happened, even if it's not the norm. Our row backs the cooling, changeable read, 19.5C over 7.5C nights feeling 6C, with 87.2mm of rain across 9.5 days. Regulars are consistent this stretch into November is genuinely tricky weather-wise, with locals themselves saying they never really know what a given week will bring, so layering plus a real rain jacket beats trusting a single forecast. The record: humidity 74 percent, 7.2 hours of sun, a 15.1 kph wind and one of the cleanest air readings in this project, AQI 35.

August is the driest month of the summer here on the board's own reckoning, which is a relative claim: our row still carries 88mm across 9.3 days, arriving as the short heavy thunderstorms they say July and August specialise in. The other local observation is that the cloud and the humidity keep the temperature from swinging, so a hot day stays hot and a cool one stays cool; our 29C reads as 31C at 76 percent humidity, over 17C nights. The rivers are what the city does with a summer evening - the trails along them and the boats on them. Sun is generous at 10.7 hours inside 13.7 of daylight. The record: a dew point of 17.6C and AQI 58.

June is where the year changes character here, and regulars describe both ends of it: cool sunny days and all-day spring rain at the start, hazy humid ones with short thunderstorms by the finish. Highs can be anywhere from the sixties to the nineties, with the upper seventies and low eighties likeliest - our row gives 27.5C reading as 29C over 14.7C nights. June is also the month most likely to produce a whole day of rain rather than a burst, and our 98.5mm across 9.1 days carries both patterns. The cloud and humidity keep the days from swinging much, so the heat that builds tends to linger. The record: 10.9 hours of sun and AQI 67.

Pittsburgh-forum threads on May weather describe genuine spring: T-shirt days with a light jacket or hoodie for the evenings, frosts finally behind for the year, and the occasional 80-degree Fahrenheit afternoon that posters say is really borrowing from June rather than typical May. The standing advice is to pack long pants plus that light layer and check the forecast close to the trip, since the month runs changeable rather than settled. Rain shows up on close to half the days by some counts, which the record backs: 22.5C days, 10.4C nights, 109mm of rain across nearly twelve days and 9.8 hours of sun - spring here means real rain, not just the odd shower.