Those swirling lines and triangular symbols on a weather map are a language. Once you can read it, a single chart tells …
Sharing your station’s data to networks like Weather Underground and the Ambient network is free, easy, and turns your h…
Measuring air temperature accurately is far harder than it looks, and most home stations get it wrong for one avoidable …
Fog is simply a cloud at ground level, but the different ways it forms explain why some mornings are socked in and other…
A heat dome can lock a region into days of dangerous, record-breaking heat. The mechanism behind it is a particular trap…
La Niña reshuffles weather patterns across the globe in broadly predictable ways. Here’s what the pattern is, and the ki…
Rennes, the capital of Brittany, sits in the east of the region at the confluence of two rivers, about 60 km inland from the English Channel at approximately 48.11°N, 1.68°W. Its position in the Breton interior gives it a temperate oceanic climate (Köppen Cfb) — mild, changeable and moderated by the Atlantic — with warm summers, mild winters and rain spread through every month, though slightly drier than the Breton coast.
Summer, from June to August, is warm and pleasant, with July and August the warmest months — average highs around 24–25°C — and occasional heatwaves that can exceed 35°C. It is the driest, sunniest season, though Atlantic fronts keep it changeable and showers can arrive at any time; the maritime influence keeps the heat comfortable and the nights cool.
Winter, from December to February, is mild and damp, with January the coolest month — average highs around 9°C and lows near 3°C. Frost occurs on clear nights, but snow is rare and rarely lies; the season is dominated by grey, wet, windy weather as Atlantic depressions sweep in off the Channel and the Bay of Biscay, giving Brittany its reputation for frequent rain.
Rennes receives around 690–700 mm of rain a year, spread through every month with an autumn and winter maximum and a drier summer; its inland position makes it somewhat drier than Brittany's exposed western coast, and rain tends to be light and frequent rather than heavy. Live rainfall, humidity, and pressure readings for the city are shown in the panels above.
Rennes shares Brittany's mild, damp, breezy oceanic climate, though its position in the sheltered eastern interior spares it the worst of the Atlantic weather that lashes the region's western capes. The frequent light rain that keeps the Breton countryside green is proverbial, and autumn and winter storms rolling in off the Atlantic are the region's most dramatic weather.
To follow any single measurement in Rennes 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.