The magnetic compass is an old Chinese invention, probably first made in China during the Qin dynasty (221-206 B.C.). Chinese fortune tellers used lodestones (a mineral composed of an iron oxide which aligns itself in a north-south direction) to construct their fortune telling boards.
Guide to Pennsylvania weather in April. The average maximum daytime temperature in Pennsylvania in April is a comfortable 17Â°C (63Â°F). The average night-time temperature is usually a cold 5Â°C (41Â°F). There are usually 7 hours of bright sunshine each day, which represents 55% of the 13 hours of daylight. Expect 95mm (3.7 inches) of rainfall across the whole of April with 11 days with some rain falling.
Days of Hot Weather in Philadelphia. The temperature at Philadelphia climbs into the 90s Fahrenheit for 24 days a year on average, scattered throughout late spring and summer. About once every two or three years, the thermometer here reaches 100 Â°F (38 Â°C).A day of 100-degree weather can show up in July or August.he coldest nights of winter at Philadelphia drop down to 10 Â°F (-12 Â°C) or below. About once in five years the city gets as cold as 0 Â°F (-18 Â°C). From December to March, Philadelphia can remain below freezing all day long. The city typically has 13 days a year when the temperature never rises above 32 Â°F.