Everyday conversations often begin with comments on the short and long term vagaries of the weather. Short term changes relate to rather sudden shifts. For example, one sunny summer or autumn day could be followed by stormy weather the next. Or, a cold front could lower the temperature substantially overnight. In contrast, seasonal shifts are noticed over several weeks or months. Potential for the first frost of autumn intensifies during late September or early October, with a killing frost possible by around mid October. Our current post relates to seasonal declines and how they relate to optimism for the future.
(Our weather posts are based on your blogger’s residence in the Upper Midwest. All our lives we have resided close 40-42º N. Latitude. In more northern latitudes many meteorological and astronomical effects are intensified; in latitudes to our south effects are diminished. In the Southern Hemisphere the effects are reversed! Astronomical and meteorological statistics are available for tens of thousands of locations on Earth.)
At this writing shortened day length and decreased sun angle are taking a toll on our temperatures in Northern Illinois. In the third week of October the lower sun angle contributes to weaker solar intensity. Day length has diminished more than four hours since the June 21 summer solstice. Sunrise is almost two hours later; sunset is more than two hours earlier. When winter solstice occurs on December 21, duration of daylight will be diminished about six hours. Solar heating from the sun’s radiation is less intense and occurs over a shorter time while Planet Earth radiates away more of its heat during the longer night. Average temperatures, therefore, fall when Earth loses more heat than it gains.
In January and February average temperatures do not fall any further. In the long term, Earth is generally losing its heat but gaining an equal amount from the Sun. Cold air masses move over the land more frequently and dominate our winter conditions. Air mass movements help generate meteorological variety. Winter weather enthusiasts are happy but some human “snow birds” escape to warmer climates at lower latitudes.
Generally stable, cold temperatures in January and February presage hope for those residents who prefer natural warmth. For them, help is on the way. Earth’s stable axis tilt results in increasing sun angles, earlier sunrises, later sunsets, longer days, and increasing temperatures as the planet continues its annual 365 day revolutionary cycle. At the December 21 winter solstice the Northern Hemisphere points farthest away from the Sun. Astronomers and meteorologists alike remind us that seasonal renewal is in prospect. One interesting sidelight is that significant temperature increases take about two months to become apparent. The general balance of heat gain and heat loss remains fairly even for weeks after the winter solstice. With increasing Sun angle, warmer temperatures will soon follow. Increased heat gain will predominate over heat loss. Future seasonal renewal is in prospect even during the decline of Autumn and the approach of cold winter months.
Our weather/astronomical system is a phenomenon of intricate beauty. Earth’s seasonal cycle has all the hallmarks of Intelligent Design. We do not shrink from proclaiming that the Intelligent Designer is the Creator of All Things. God has endowed living things with the potential to adjust to cycles of seasonal change. Some plants and animals adapt to decreasing temperatures and remain in cold conditions all year long. Their perseverance is rewarded when warm seasons return. Many animals adapt by migrating seasonally. Inherently, they know what is best for their healthy survival.
Planet Earth is “a place to thrive.” Living creatures possess the God-gifted ability to manage and adapt to a broad range of environmental conditions, including seasonal changes. We are reminded of our ability to cope with changing seasons as we examine God’s statement to Noah in Genesis 8:22 (NIV): As long as the earth endures, seedtime and harvest, cold and heat, summer and winter, day and night will never cease.