Geography of Sheffield (Totley Brook passes south of Totley and meets Old Hay Brook at Needham's Dyke). The Sheaf flows northwards to join the River Don near Blonk Street Bridge in the city centre. This lower section of the River Sheaf together with the River Don, between the present Blonk Street and Lady's Bridge, formed part of the perimeter of Sheffield Castle. Porter Brook's source is just inside the Peak District National Park, to the west of the city, at Clough Hollow, also near Ringinglow. From here it flows eastward to meet the Sheaf, at a point now located underneath Sheffield Midland Station.
Sheffield part of which lies within Brighton and Hove. Like the rest of the United Kingdom, the climate in Sheffield is generally temperate. The Pennines to the west of the city can create a cool, gloomy and wet environment, but they also provide shelter from the prevailing westerly winds, casting a "rain shadow" across the area. Between 1971 and 2000 Sheffield averaged of rain per year; December was the wettest month with and July the driest with . July was also the hottest month, with an average maximum temperature of . The average minimum temperature in January and February was ,