Condensation trails left behind by jet airliners are composed of ice crystals formed by the exhaust of jet engines in areas with sufficient water vapor. Conspiracy theories suggesting these trails are "chem trails" produced by governmental agencies for nefarious purposes have no basis in fact. That didn t stop the state of Tennessee from passing a bill to prohibit them.
Weather apps for smart phones provide convenient access to current weather and forecasts. They can provide information on high temperatures, precipitation, air quality, and other weather conditions. Some apps also include live weather radar and severe weather alerts.
The National Weather Service calculates a probability of precipitation, or PoP, which describes the likelihood of measurable rain (at least 0.01 inches) occurring in a given time in the forecast area. The PoP is calculated by multiplying two factors: the certainty that rain will fall and its widespread coverage. While expressing the precipitation forecast as a single-event probability can cause confusion, understanding the probability of precipitation as a percentage can help with planning outdoor activities.
The Plant Hardiness Zone Map (PHZM) developed by the U.S. Department of Agriculture has been updated in 2023, reflecting the influence of global warming. The revised map shows that half of the country has shifted to a warmer half zone, while the other half remains in the same half zone. However, the hardiness zones cannot account for all climate and weather conditions, so it is recommended to consult local master gardeners and nurseries for planting plans.