Before my late father began a career as a pastor and then a religious scholar, he was trained as a weather forecaster.
He learned this discipline at first in university, but later in the United States Air Force.
As a scientist training in the observation of the weather, he always took this matter into consideration when it came to his research studies dealing with the Bible.
A number of books that he wrote which he has been recognized for from an academic point of view dealing with the birth of Jesus Christ come to my mind at this time of year.
What is interesting though as far as I can remember, the only point that he mentioned concerning the matter of the weather and its relevance concerning the time Jesus was born is the following quotation from his book "The Star of Bethlehem: The Star that Astonished the World."
"Luke said that Jesus was born at a time when his parents went to Bethlehem in response to Caesar's command for a census. Ramsay showed that considerable confidence can be placed in the belief that the general time of the year for the start of a census was from August to October. The September period for Jesus' birth we are suggesting fits this well.
A late Summer or early Autumn date for Jesus' birth has also been suggested because Luke said the shepherds were tending their flocks at night at his nativity (Luke 2:8). Many have believed this precludes a wintertime birth (either early Winter on December 25th or a late Winter in early March) because it would have been too cold for the flocks to be out in the open at that time.
But this evidence is very problematic. In exceptionally cold Winters this may have been the case, but in mild Winters sheep are often out of doors in Palestine all night. Since no one knows what kind of weather there was in Palestine the year of Jesus birth (either severe or mild), this factor can be of no chronological value." (Martin, pg. 183-4)
The thing is though, in one way we do know what kind of weather there would have been in the land of Israel during this time especially if we say that Jesus was born in late December. Baly shows us the basic seasonal pattern that has existed in the Holy Land for 1,000s of years. It is important because it shows the environment that people who lived in the land would have known about very well. Because of this, the idea that Joseph and Mary would have set out on a trip to Bethlehem in December makes no sense at all in a practical sense.
“The Palestinian year is divided into two major seasons, the dry summer from mid-June to mid-September and the rainy season in the cooler half of the year. The summer drought, during which no rain falls at all, is actually somewhat longer than the true ‘summer’ and extends into the transitional seasons which dive the summer from the winter at either end. Thus, even on the coast of Cis-Jordan (Israel), the drought is usually complete for five continuous months from the middle of May to the second fortnight in October. It is better to avoid using the word “winter” for the rainy season, for winter inevitably suggests to an English-speaking person a cold season, but in Palestine, the cold weather is normally confined to the three months after Christmas, that is to the second half of the rainy season. In modern Arabic, the word “summer” is so emphatically suggestive of the long dry period (cf. Ps. 32:4, ‘My strength was dried up as the heat of summer”) that winter means more than anything else that blessed period when the rain comes. The Arabic word shittah is in fact used impartially for both “winter” and “rain” and there seems to be something of the same thought in Song of Solomon 2:11, “ For lo, the winter is past, the rain is over and gone.” (Baly, The Geography of the Bible, pg. 43)
This description by Baly is 100% correct as anyone who lives here in the land knows. Anytime after October 15, the rainy season starts and in the beginning of that season, the rains start in a sporadic way, but get into December and there is a regular occurrence of rainstorms that come systematically and after January those storms will get more intense.
As Professor Ramsay mentions, the idea the Romans would undertake a census during the rainy season moving to the middle of winter makes zero sense at all.
September though would have been a very suitable time for such a journey to take place and be completed before the beginning of the olive harvest, which was a very important annual agricultural event in ancient times as it still is today.
During September, the days are long and warm and the nights are mild and not cold at all.
Knowing the weather and the seasons of the Bible lands in a practical sense helps us better understand the stories of the Bible especially those ones we hold so dear to our hearts and minds.