Quick Reference The 50-degree line. Below 50 degrees Fahrenheit, almost no warm-season seeds will germinate. Above 50, cool-season crops thrive. How to measure: Soil thermometer, 4 inches deep, in the morning, in the planting bed itself. Cool-season crops (germinate at 40-65 degrees): Lettuce, spinach, peas, kale, radishes, beets, carrots, onions, broccoli, cabbage, cauliflower. Warm-season crops
Quick Reference Humidity: Water vapor in the air, in invisible gas form. Three types: Relative humidity (a percentage), absolute humidity (grams per cubic meter), specific humidity (grams per kilogram of air). Dew point: The temperature at which the air would be 100 percent saturated. The cleaner outdoor-comfort measure. Why warm air feels mugger: Warm air
Quick Reference What it is: A blood moon is a total lunar eclipse, when Earth’s shadow falls completely across the Moon and the Moon turns deep red or copper. Why red: Earth’s atmosphere bends red wavelengths of sunlight through the shadow and onto the Moon. Same physics as a sunset. NASA terminology: NASA calls it
Quick Reference What it is: A large area of cold low-pressure air that circulates around each pole. Always there, always strongest in winter. Two layers: A stratospheric polar vortex (10 to 30 miles up) and a tropospheric polar vortex (lower, where weather happens). Strong vortex: Cold air locked at the pole. Winter cold stays north.
Quick Reference The two main numbers: Kp index (0 to 9, planetary geomagnetic activity) and the G-scale (G1 minor through G5 extreme storms). Kp 5 (G1 minor): Aurora possible across far northern US, including Maine, Michigan, Minnesota, Wisconsin, and the Dakotas. Kp 7 (G3 strong): Aurora visible as far south as Pennsylvania, Iowa, and northern
Quick Reference Severe threshold: Hail of 1 inch or larger is officially severe per the National Weather Service. 1-inch hail can dent vehicles and damage roofs. Hail size scale: Pea (0.25″), marble (0.5″), penny (0.75″), quarter (1″), golf ball (1.75″), tennis ball (2.5″), baseball (2.75″), softball (4″), grapefruit (4.5″+). Largest US hailstone: Vivian, South Dakota,
Quick Reference What it is: Body core temperature below 95 degrees Fahrenheit (35 degrees Celsius). Mild (90 to 95): Shivering, slurred speech, fast heart rate, fatigue, mild confusion. Watch for the “umbles”: stumbles, mumbles, fumbles, grumbles. Moderate (82 to 90): Violent shivering that then stops, severe confusion, drowsiness, slow weak pulse, blue lips and fingers.
Quick Reference Created: 1805 by Royal Navy Rear-Admiral Sir Francis Beaufort. Range: Force 0 (calm, less than 1 mph) through Force 12 (hurricane, 73 mph and above). Original purpose: Standardize sailing condition reports across the British Navy. Adopted: Royal Navy 1838, internationally 1853, land observations added 1916. Why still used: Lets observers describe wind without
Learn how these storms form and why they’re so serious.
Hurricane season begins June 1st! What signs from nature did our ancestors watch to warn against weather’s fiercest storm? Check out the list and watch the cows and alligators.
