Wind Speed

WIND SPEED (km/h)	WHAT TO LOOK FOR
10	Wind felt on face; leaves rustle; wind vanes begin to move.
20	Leaves & small twigs constantly moving; small flags extended.
30	Dust, leaves, & loose paper lifted; large flags flap; small tree branches move.
40	Small trees begin to sway; large flags extend and flap.
50	Larger tree branches moving; whistling heard in power lines; large flags extend and flap more wildly.
60	Whole trees moving; resistance felt in walking against wind; large flags extend fully and flap only at the end

Wind Chill Index

Temperature (°C) Wind Speed (km/h)	0	-5	-10	-15	-20	-25	-30	-35	-40	-45
10	-3	-9	-15	-21	-27	-33	-39	-45	-51	-57
20	-5	-12	-18	-24	-31	-37	-43	-49	-56	-62
30	-7	-13	-20	-26	-33	-39	-46	-52	-59	-65
40	-7	-14	-21	-27	-34	-41	-48	-54	-61	-68
50	-8	-15	-22	-29	-35	-42	-49	-56	-63	-70
60	-9	-16	-23	-30	-37	-43	-50	-57	-64	-71

Notes regarding wind chill

1. For a given combination of temperature and wind speed, the wind chill index corresponds roughly to the temperature that one would feel in a very light wind. For example, a temperature of -25°C and a wind speed of 20 km/h give a wind chill index of -37. This means that, with a wind of 20 km/h and a temperature of -25°C, one would feel as if it were -37°C in a very light wind.

2. Wind chill does not affect objects and does not lower the actual temperature. It only describe how a human being would feel in the wind at the ambient temperature.

3. The wind chill index does not take into account the effect of sunshine. Bright sunshine may reduce the effect of wind chill (make it feel warmer) by 6 to 10 units.

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