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View Poll Results: Of the three major definitions of a season, which do you consider to be "valid"?
Astronomical (Solar) 7 28.00%
Meteorological 15 60.00%
"Official" (invented by Romans, appears on calendars) 7 28.00%
Multiple Choice Poll. Voters: 25. You may not vote on this poll

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Old 10-02-2019, 12:57 PM
Location: Putnam County, TN
232 posts, read 47,353 times
Reputation: 138


Some posts from another thread have led to the idea that the Roman origin of season definition is a "new perspective and talking point."

Originally Posted by Sun Belt-lover L.A.M. View Post
It's actually somewhat cooler then than in June unless you're on certain coasts, but you're right that U.S. summers tend to feel longer. Subtropical regions (South, Southwest, Mid-Atlantic) tend to have longer, hotter summers and shorter, milder winters by nature, while temperate North American (excluding PNW) regions are often longer/more intense in summer AND winter.

However, don't forget, there are places like Siberia, Iceland, parts of Alaska, parts of northern Canada and parts of northern Europe where leaves actually will change and even drop as early as August. The meteorological definition of a season (Jun-Aug, Sep-Nov, Dec-Feb, Mar-May) is more like a general guideline to warmer/colder temperatures, and the more common definition (NOT the true astronomical one; that would be having solstices and equinoxes as the mid-season) was invented by the Romans because the Mediterranean Sea lags their seasons more.

I've grown to learn that the definitions of seasons are very subjective and can vary regionally, which can make for some interesting discussions (including this one!).
Originally Posted by forgotten username View Post
I definitely consider september to be a summer month here, at least the first half of it. Summers are long, but then they're also quite hot. I would probably feel differently if I lived in Helsinki, but that's a different climate. Kinda like comparing Duluth with Kansas City.

But yeah I think it all depends on what you're used to, I have yet to meet a Canadian here so he can tell me about how he feels about our winter.
Originally Posted by jbgusa View Post
I never thought about the Roman origin of season definition. That is a new perspective and talking point!
If you're interested, you can watch this video:
Why Seasons Make No Sense

What do I consider a season? Well, please note that I live in a subtropical region and am thus used to seeing milder and hotter averages.

Autumn: It takes until mid to late October for our summer heat to finally wear off and leaves to start changing big-time. Our first frost date is around October 28, seldom happening before October 10 or after November 13. It usually takes until late November or early December for all leaves to drop and average highs to drop below 55F, even though the peak of autumn colors happens in late October/early November.

Winter: Averages below 55F usually set in around late November or early December. Our annual mean minimum temperature is around 5F, placing us in USDA Hardiness Zone 7a. Most of the native vegetation is deciduous, but there are some conifers, hollies, mountain laurels and river canes mixed in. With an average winter temperature over 36F in the winter, subtropical plants like Needle Palm, Dwarf Palmetto, Southern Magnolia and Winter Pansy survive with little to no difficulty. Snow cover is present less than 10% of the average winter, and average highs begin to warm back up to pleasant levels in mid to late February.

Spring: While we can have cold days anytime in February and remain cold in early February, late and sometimes mid February are more spring-like. Buttercups, daffodils, tulips and hyacinths begin to bloom. Our "brown phase" that lasted from mid/late November ends around late February/early March with the return of cherry blossoms and Bradford Pears. Our leaf-outs usually occur in early April, but leaf-outs in late March are not uncommon. Our last frost happens around April 6, seldom happening before March 23 or after April 21. Heat begins to set in around late April to early May.

Summer: Heat begins to set in around late April to early May, but it's generally not the severe heat our area is known for until around early to mid June. The humidity still hasn't fully risen from the winter until around the last week of May or first week of June, but things get extremely uncomfortable and potentially dangerous when it does. Most of our hottest weather usually occurs between late June and early August, with highs regularly topping 90F and lows failing to fall to 70F in July. Our annual mean maximum is between 95F and 100F, but the infamous heat wave in June 2012 sent much of Middle TN into the upper 100s and scattered portions into the lower 110s. In September, humidity sticks around, making it more uncomfortable than May despite not being much hotter; this can be worse in some years due to late-season droughts raising temperatures, making deciduous plants dormant early and lowering water levels. Only around mid to late October does summer heat fully wear off, and hot days as late as mid November are not completely unheard of.

Of the three major definitions of a season, which do you consider to be "valid"?
--Astronomical: Based purely off of daylight hours and sun angle, so the solstices and equinoxes are actually mid-season.
--Meteorological: This goes in line with the warmest three months (June, July and August in non-tropical northern hemisphere) as summer, coldest three (December, January and February) as winter and spring/autumn to fill the respective gaps (MAM and SON).
--"Official": These are the seasons that appear on most calendars, at least in the contiguous U.S. They go by the solstices and equinoxes as the start of the season, which is only accurate temperature-wise in some coastal regions. This definition has Roman origins, and they were lagged and moderated by the Mediterranean Sea.

Last edited by Sun Belt-lover L.A.M.; 10-02-2019 at 01:24 PM..
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Old 10-02-2019, 01:32 PM
7,060 posts, read 4,394,826 times
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I don't live in a traditional four-season climate, but the definition of "official" matches up best with my reality.

For example, having "summer" start late in June and end late in September would more accurately predict our actual summer season than either of the other models. Our hottest months are July, August, September.
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Old 10-02-2019, 01:50 PM
Location: Norman, OK
2,630 posts, read 1,238,189 times
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Most people call the "official" season definition the astronomical one and the one you call astronomical the solar one. What's funny is that in Oklahoma Dec. 1-Feb. 28 works best for winter but June 21-Sept. 23 works best for summer.
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Old 10-02-2019, 04:19 PM
Location: Seattle Area
817 posts, read 182,363 times
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Astronomical (solar definition, summer starts in early May, winter starts in early November, etc.) is the only one with a hard scientific basis that is not refutable because it applies globally. However, very few or no places have seasons that actually correspond to astronomical seasons. It's accurate in terms of day length and sun angle though, so I'll say it's valid for what it's worth.

Meterological is pretty arbitrary for the most part. The actual warmest/coldest months depends on where you live. It's ridiculous for summer to be considered June 1 - August 31 in Delhi and in San Francisco. Same with "official" astronomical seasons that start on or around March/June/September/December 21.

In terms of what works for weather, the answer is none of the above. Spring, summer, fall, and winter start at different times depending on location. In practice it even depends on the weather for the particular year.
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Old 10-03-2019, 02:47 AM
Location: Bologna, Italy
6,460 posts, read 3,716,229 times
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I think we answered something similar elsewhere recently. Like how people define the seasons, and I think I answered something based on the weather more than on the dates. But then I also said that unusually cold weather during the warm season, or the opposite, did not constitute an actual dip into winter or summer.
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Old 10-03-2019, 04:33 AM
Location: White House, TN
5,760 posts, read 4,049,930 times
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I generally like to look at winter, at least in a C or D-group climate, as the period when average temperatures are within about 20% of the coldest mean, and summers within about 20% of the warmest mean. If smoothed daily means are available, those should be used.

Hottest day where I live is a mean of 79.6 F / 26.4 C on July 20, coldest day is 37.3 F / 2.9 C on January 12.

The difference between those is 43.3 F / 23.4 C, and 20% of that is 8.7 F / 4.8 C. That puts the thresholds for winter and summer at 37.3 + 8.7 = 46.0 F / 7.7 C and 79.6 - 8.7 = 70.9 F / 21.6 C.

Winter: November 26 - March 2, peak of 37.3 F / 2.9 C on January 12
Spring: March 3 - May 28
Summer: May 29 - September 17, peak of 79.6 F / 26.4 C on July 20
Fall: September 18 - November 25

As you can see, the seasons aren't even length, but they match up much better with the meteorological seasons than the astronomical seasons; the ideas of March 19 being winter, June 19 being spring, and December 19 being fall is laughable where I live (although in some individual years the aforementioned dates can resemble those seasons, they very rarely would all match up). The summer/fall border is an exception; summer tends to end late here.

The meteorological seasons, however, DO match up very well with three of the four seasons as well as the beginning of summer. Winter's start and end are both very close to Dec. 1 - Feb. 28/29. Same for spring and Mar. 1 - May 31. Summer starts around the June 1 it's supposed to, but ends later than Aug. 31; it's a longer season. While fall doesn't start near the Sept. 1 it's supposed to, it ends near the Nov. 30 that it's supposed to.

Overall, I would use the meteorological seasons where I live, with the exception that the first half of September is still summer. So Dec - Feb are winter, Mar - May are spring, June - Sept. 15 are summer and Sept. 16 - Nov are fall.

I got my smoothed daily means from https://w2.weather.gov/climate/xmacis.php?wfo=ohx, the NOWData tab, then Daily/Monthly normals, choose Daily.
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Old 10-03-2019, 10:43 AM
Location: Coastal Georgia
37,657 posts, read 46,512,446 times
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Summer here in coastal GA is April to October. Fall is November and December. Winter is Jan and Feb. Spring is March.
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Old 10-03-2019, 11:21 AM
8,350 posts, read 5,264,653 times
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In the Lower Midwest, summer begins in mid-May (though in recent years this has been lagging by a couple of weeks) and continues through early October. In mid-October the temperature drops abruptly. Fall is therefore about a month, from mid-October to mid-November. Winter is mid-November through mid-April. Spring is the 3-4 week period between the final snowfall (typically mid-April) and the first day in the 80s (mid-May).

Thus, this "4 season" climate is effectively two seasons: long, hot, humid and wet summer.... and long, cold, humid and wet winter. Both are miserable.
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Old 10-03-2019, 12:43 PM
Location: Moku Nui, Hawaii
9,906 posts, read 19,189,638 times
Reputation: 8922
There could be some better ways to notice seasons, I suppose, but it's not likely to find a system that is going to work over the entire planet since there's so many different seasons. Plus the Southern hemisphere is in opposition to the Northern hemisphere. Us folks here near the middle kinda ignore the whole season thing, anyway.

Summer is when there's no whales, winter is when there's whales. The first humpback whale just showed up off of Maui yesterday, so I guess we're officially doing winter now. The avocados are getting ripe as well, that's sorta a winter thing, too. Pineapples are sorta a summer thing and they've all been eaten, so I suppose it's wintertime.
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Old 10-03-2019, 01:27 PM
3,995 posts, read 1,059,287 times
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To me, my choice of activities is based on the weather. I internally "feel" that "summer" is however long the weather is more often than not in the 80's and above each week. Which, in NC, is 8 months out of the year.
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