Auburn-Opelika Airport
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Auburn-Opelika Airport clear sky chart from 2005-11-06 to 2024-04-03.

This page is a summary of past forecasts. Even though it's based only on forecasts, some people use these pages as clue to a site's climate. But climate data based on actual observation should be preferred (if you can find it!).

Cloud, Transparency and Seeing forecasts are summarized individually. But because good observing conditions require a combination of minimum cloud cover, transparency and seeing, the individual forecast summaries can be difficult to interpret. The observing conditions section counts the combinations of conditions needed for common types of astronomical observation.

Observing Conditions

The following tables count the occurrence of the combinations of forecast and darkness conditions needed for different observations. Conditions are rated by by what percentage of the hours the observation would likely be attempted are usable.

Observation Type	Minimum conditions for hour to be usable				Out of hours
	Clear of Clouds	Transparency	Seeing	Sky Brightness
Planetary:	50%	(no limit)	Average	(no limit)	Nighttime Hours
Deep Sky:	70%	Average	(no limit)	5.9	Nighttime Hours
CCD Imaging:	70%	Below Average	Poor	(no limit)	Nighttime Hours

Percentages are of nighttime hours per month, or per year, when a particular observing conditions was met. Deep Sky percentages never exceed 50% because the moon is up half the time. Deep sky percentages are much lower for charts at high latitudes because of fewer dark hours in the summer.

Overall

By Month

Individual Forecasts

The length of each colored bar in the "occurrence of each Forecast" column is proportional to the number of times the chart forecast that color. The percentages are of the total number of hours per month, or per year, with a particular forecast. The colors as the same as those used in clear sky charts.

Note: Transparency probabilities are only counted for those hours that have 30% or less cloud cover. Seeing probabilities are only counted for those hours that have 80% or less cloud cover. If that's too tricky, try Observing Conditions instead.

Overall

		Occurrence of each Forecast	Data Points
Cloud Cover	Day	13% 6% 2 5% 5% 3 5% 5% 6% 8% 42%	79308
	Night	12% 6% 2 5% 5% 3 4 5% 5% 8% 45%	80825
Transparency	Day	38% 8% 11% 18% 18% 6%	79031
	Night	37% 7% 11% 18% 20% 8%	80621
Seeing	Day	14% 9% 22% 25% 20% 10%	13908
	Night	14% 7% 24% 30% 21% 4	24025

By Month

Percentage Cloud Cover SE (2006-)
Color Meanings: Overcast 90% covered 80% covered 70% covered 60% covered 50% covered 40% covered 30% covered 20% covered 10% covered Clear
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	17% 9% 3 5% 4 3 3 4 5% 6% 40%	2836
	11th to 20th	Day	12% 5% 2 4 3 2 3 4 5% 7% 53%	2851
	21st to end	Day	23% 9% 3 5% 3 2 3 3 4 5% 40%	3476
February	1st to 10th	Day	17% 7% 4 5% 6% 3 4 3 5% 7% 38%	1900
	11th to 20th	Day	20% 7% 2 5% 4 3 3 4 4 5% 43%	1848
	21st to end	Day	16% 8% 3 6% 4 3 5% 4 4 7% 39%	1570
March	1st to 10th	Day	15% 6% 2 5% 4 2 4 4 5% 5% 47%	1900
	11th to 20th	Day	17% 6% 3 5% 5% 3 5% 5% 5% 6% 40%	2085
	21st to end	Day	15% 6% 2 4 5% 2 4 5% 5% 8% 44%	2299
April	1st to 10th	Day	13% 5% 3 5% 4 3 5% 5% 5% 8% 45%	2146
	11th to 20th	Day	13% 5% 2 5% 4 3 5% 4 5% 7% 46%	2134
	21st to end	Day	8% 4 2 4 4 3 5% 5% 5% 8% 53%	2192
May	1st to 10th	Day	9% 4 2 4 4 3 4 4 5% 8% 51%	2340
	11th to 20th	Day	8% 4 2 5% 6% 4 5% 6% 6% 9% 44%	2301
	21st to end	Day	9% 5% 2 5% 5% 3 5% 6% 7% 9% 43%	2531
June	1st to 10th	Day	10% 6% 3 6% 7% 4 7% 7% 8% 10% 32%	2340
	11th to 20th	Day	7% 3 1 4 6% 5% 7% 7% 8% 11% 41%	2340
	21st to end	Day	6% 5% 2 7% 7% 5% 8% 7% 9% 11% 34%	2340
July	1st to 10th	Day	9% 5% 3 5% 7% 5% 8% 9% 9% 11% 29%	2340
	11th to 20th	Day	8% 6% 3 6% 8% 5% 7% 8% 8% 11% 30%	2340
	21st to end	Day	8% 5% 2 5% 8% 5% 7% 7% 9% 12% 32%	2547
August	1st to 10th	Day	7% 4 2 6% 6% 5% 7% 8% 9% 14% 32%	2184
	11th to 20th	Day	12% 6% 2 7% 6% 5% 7% 6% 8% 11% 30%	2125
	21st to end	Day	12% 7% 3 5% 7% 5% 7% 7% 8% 9% 31%	2376
September	1st to 10th	Day	9% 6% 3 7% 7% 5% 7% 7% 6% 8% 37%	2035
	11th to 20th	Day	13% 6% 2 6% 5% 4 5% 6% 6% 7% 40%	1980
	21st to end	Day	11% 4 2 5% 6% 3 5% 5% 5% 6% 48%	1980
October	1st to 10th	Day	10% 6% 2 4 5% 2 3 4 4 6% 53%	1980
	11th to 20th	Day	10% 4 2 3 3 2 3 5% 5% 7% 55%	1972
	21st to end	Day	12% 5% 2 4 4 3 3 4 4 5% 55%	1941
November	1st to 10th	Day	11% 6% 2 3 4 3 4 4 4 4 55%	1672
	11th to 20th	Day	13% 4 2 3 4 2 4 3 4 5% 56%	1710
	21st to end	Day	14% 5% 2 5% 4 3 5% 4 5% 6% 46%	1710
December	1st to 10th	Day	17% 5% 2 5% 5% 3 5% 5% 4 7% 42%	1710
	11th to 20th	Day	17% 7% 3 5% 5% 3 4 3 4 5% 42%	2153
	21st to end	Day	21% 7% 3 5% 5% 3 3 4 4 6% 38%	3124
January	1st to 10th	Night	17% 11% 2 4 4 3 4 4 4 5% 41%	4109
	11th to 20th	Night	12% 6% 2 5% 5% 3 4 4 5% 6% 47%	4106
	21st to end	Night	23% 11% 2 5% 4 2 3 3 3 4 40%	4180
February	1st to 10th	Night	15% 7% 4 6% 6% 3 4 3 4 6% 43%	2280
	11th to 20th	Night	20% 6% 2 5% 4 2 3 4 4 5% 44%	2218
	21st to end	Night	16% 7% 3 5% 5% 3 4 4 5% 7% 42%	1884
March	1st to 10th	Night	14% 6% 3 5% 3 3 4 4 4 6% 48%	2280
	11th to 20th	Night	13% 6% 3 5% 5% 3 5% 5% 6% 7% 43%	2095
	21st to end	Night	12% 6% 2 4 4 2 4 4 6% 7% 48%	2299
April	1st to 10th	Night	11% 4 3 4 7% 2 5% 6% 5% 7% 46%	1872
	11th to 20th	Night	13% 5% 2 4 3 2 3 4 5% 9% 49%	1775
	21st to end	Night	7% 4 2 4 4 3 4 4 4 8% 56%	1764
May	1st to 10th	Night	7% 3 2 4 5% 2 4 4 6% 6% 55%	1620
	11th to 20th	Night	7% 6% 3 7% 5% 3 6% 6% 6% 8% 44%	1592
	21st to end	Night	7% 5% 2 5% 5% 4 5% 5% 6% 9% 46%	1744
June	1st to 10th	Night	7% 6% 2 8% 7% 5% 7% 6% 8% 11% 34%	1620
	11th to 20th	Night	4 4 2 5% 4 3 6% 6% 8% 11% 46%	1620
	21st to end	Night	5% 5% 2 5% 6% 4 6% 7% 8% 13% 39%	1620
July	1st to 10th	Night	5% 5% 2 5% 6% 5% 7% 10% 10% 12% 32%	1620
	11th to 20th	Night	5% 5% 3 7% 5% 5% 6% 6% 9% 13% 37%	1620
	21st to end	Night	5% 4 2 5% 5% 4 7% 8% 8% 14% 39%	1771
August	1st to 10th	Night	5% 5% 2 6% 6% 4 7% 8% 8% 13% 36%	1748
	11th to 20th	Night	9% 5% 3 4 6% 4 5% 6% 8% 11% 37%	1776
	21st to end	Night	12% 7% 3 6% 5% 3 5% 5% 7% 9% 37%	1980
September	1st to 10th	Night	8% 5% 2 5% 6% 3 5% 7% 7% 9% 43%	1905
	11th to 20th	Night	11% 6% 3 6% 4 3 4 6% 6% 7% 43%	1980
	21st to end	Night	8% 5% 2 5% 5% 3 5% 4 5% 7% 50%	1980
October	1st to 10th	Night	7% 4 2 5% 3 2 4 3 5% 7% 58%	1980
	11th to 20th	Night	9% 4 2 4 4 2 3 4 4 7% 56%	1985
	21st to end	Night	11% 5% 2 4 4 2 3 3 3 4 57%	2412
November	1st to 10th	Night	9% 4 2 4 3 2 3 5% 4 5% 58%	2406
	11th to 20th	Night	12% 5% 2 4 4 2 3 3 4 5% 56%	2470
	21st to end	Night	13% 6% 2 6% 4 3 3 4 4 6% 49%	2470
December	1st to 10th	Night	17% 5% 2 5% 5% 3 4 4 4 6% 45%	2470
	11th to 20th	Night	17% 6% 3 5% 4 2 4 3 4 6% 46%	3042
	21st to end	Night	19% 7% 2 7% 5% 3 5% 4 5% 7% 36%	4532

Transparency (when cloud cover <= 30%)
Color Meanings: Too cloudy to forecast Poor Below Average Average Above average Transparent
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	44% 4 5% 18% 23% 7%	2837
	11th to 20th	Day	31% 4 5% 22% 28% 10%	2851
	21st to end	Day	47% 4 5% 13% 20% 10%	3476
February	1st to 10th	Day	47% 4 7% 16% 19% 7%	1900
	11th to 20th	Day	44% 5% 5% 15% 22% 9%	1858
	21st to end	Day	44% 5% 7% 15% 18% 10%	1570
March	1st to 10th	Day	38% 6% 8% 17% 22% 10%	1900
	11th to 20th	Day	43% 6% 10% 15% 17% 9%	2085
	21st to end	Day	38% 6% 11% 19% 20% 6%	2299
April	1st to 10th	Day	37% 6% 9% 21% 17% 9%	2146
	11th to 20th	Day	36% 5% 8% 19% 24% 8%	2134
	21st to end	Day	29% 7% 10% 22% 28% 5%	2192
May	1st to 10th	Day	31% 6% 11% 22% 25% 5%	2340
	11th to 20th	Day	34% 10% 16% 21% 16% 3	2305
	21st to end	Day	34% 9% 12% 24% 19% 2	2531
June	1st to 10th	Day	42% 12% 16% 19% 10% 2	2340
	11th to 20th	Day	32% 11% 18% 24% 12% 2	2340
	21st to end	Day	39% 13% 17% 19% 9% 3	2340
July	1st to 10th	Day	39% 17% 22% 15% 6% 1	2275
	11th to 20th	Day	43% 14% 20% 16% 6% 1	2271
	21st to end	Day	38% 15% 22% 19% 6%	2405
August	1st to 10th	Day	38% 15% 22% 21% 4	2171
	11th to 20th	Day	44% 14% 18% 14% 8% 2	2125
	21st to end	Day	45% 12% 18% 15% 9% 2	2376
September	1st to 10th	Day	42% 10% 12% 16% 16% 5%	2035
	11th to 20th	Day	40% 10% 11% 16% 18% 4	1980
	21st to end	Day	35% 7% 9% 20% 21% 7%	1980
October	1st to 10th	Day	32% 5% 10% 19% 24% 10%	1980
	11th to 20th	Day	28% 6% 7% 22% 26% 10%	1972
	21st to end	Day	31% 5% 6% 14% 31% 14%	1941
November	1st to 10th	Day	33% 4 6% 15% 28% 14%	1672
	11th to 20th	Day	31% 3 7% 17% 26% 15%	1710
	21st to end	Day	37% 5% 8% 16% 24% 9%	1710
December	1st to 10th	Day	41% 6% 10% 16% 20% 7%	1710
	11th to 20th	Day	45% 4 5% 15% 24% 8%	2150
	21st to end	Day	46% 5% 7% 19% 20% 4	3124
January	1st to 10th	Night	44% 4 6% 14% 24% 8%	4109
	11th to 20th	Night	36% 4 6% 22% 23% 10%	4106
	21st to end	Night	49% 3 4 12% 24% 8%	4180
February	1st to 10th	Night	42% 4 7% 18% 18% 11%	2280
	11th to 20th	Night	42% 5% 5% 14% 22% 12%	2219
	21st to end	Night	41% 6% 8% 16% 15% 13%	1884
March	1st to 10th	Night	36% 5% 7% 18% 21% 12%	2280
	11th to 20th	Night	38% 8% 11% 15% 20% 9%	2095
	21st to end	Night	35% 5% 10% 20% 22% 8%	2299
April	1st to 10th	Night	35% 7% 10% 18% 19% 10%	1872
	11th to 20th	Night	32% 5% 7% 22% 24% 10%	1775
	21st to end	Night	27% 5% 11% 24% 24% 9%	1764
May	1st to 10th	Night	28% 7% 11% 21% 27% 7%	1620
	11th to 20th	Night	36% 9% 15% 19% 16% 5%	1593
	21st to end	Night	32% 9% 12% 21% 21% 5%	1745
June	1st to 10th	Night	41% 11% 17% 16% 14% 1	1620
	11th to 20th	Night	28% 10% 20% 26% 14% 2	1620
	21st to end	Night	33% 12% 21% 19% 11% 3	1620
July	1st to 10th	Night	35% 18% 23% 14% 8% 2	1575
	11th to 20th	Night	34% 16% 23% 18% 7% 1	1566
	21st to end	Night	31% 12% 27% 22% 7% 1	1672
August	1st to 10th	Night	36% 13% 22% 23% 5%	1737
	11th to 20th	Night	36% 13% 22% 16% 10% 3	1776
	21st to end	Night	42% 10% 16% 17% 11% 3	1980
September	1st to 10th	Night	34% 12% 16% 18% 15% 6%	1905
	11th to 20th	Night	37% 9% 14% 18% 17% 6%	1980
	21st to end	Night	33% 7% 10% 19% 22% 8%	1980
October	1st to 10th	Night	27% 5% 11% 21% 24% 12%	1980
	11th to 20th	Night	28% 5% 8% 19% 29% 11%	1985
	21st to end	Night	31% 3 5% 15% 29% 16%	2412
November	1st to 10th	Night	29% 4 8% 16% 26% 16%	2406
	11th to 20th	Night	32% 3 5% 17% 27% 16%	2470
	21st to end	Night	38% 4 8% 16% 23% 11%	2470
December	1st to 10th	Night	40% 6% 9% 17% 22% 6%	2470
	11th to 20th	Night	40% 4 6% 15% 27% 8%	3044
	21st to end	Night	46% 6% 7% 19% 19% 3	4532

Seeing (when cloud cover <= 80%)
Color Meanings: Too cloudy to forecast Bad 1/5 Poor 2/5 Average 3/5 Good 4/5 Excellent 5/5
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	22% 22% 35% 18% 3	270
	11th to 20th	Day	17% 23% 33% 19% 7% 1	270
	21st to end	Day	23% 24% 38% 12% 2 1	297
February	1st to 10th	Day	25% 20% 36% 13% 5%	270
	11th to 20th	Day	29% 21% 34% 13% 2	270
	21st to end	Day	22% 25% 42% 11%	225
March	1st to 10th	Day	21% 20% 34% 21% 3 1	270
	11th to 20th	Day	20% 16% 34% 22% 7% 1	455
	21st to end	Day	21% 16% 33% 22% 8% 1	506
April	1st to 10th	Day	18% 16% 27% 27% 11% 2	428
	11th to 20th	Day	15% 13% 33% 22% 14% 2	412
	21st to end	Day	13% 9% 25% 32% 18% 3	420
May	1st to 10th	Day	11% 10% 25% 29% 21% 6%	423
	11th to 20th	Day	10% 2 23% 29% 25% 11%	447
	21st to end	Day	12% 4 14% 30% 26% 14%	485
June	1st to 10th	Day	13% 2 13% 31% 28% 13%	450
	11th to 20th	Day	8% 3 13% 23% 30% 24%	450
	21st to end	Day	8% 2 15% 26% 27% 22%	450
July	1st to 10th	Day	9% 2 7% 22% 35% 26%	445
	11th to 20th	Day	5% 2 7% 19% 35% 32%	444
	21st to end	Day	6% 2 6% 21% 37% 28%	488
August	1st to 10th	Day	9% 2 7% 23% 35% 25%	446
	11th to 20th	Day	10% 2 5% 19% 40% 23%	439
	21st to end	Day	13% 3 9% 26% 31% 18%	495
September	1st to 10th	Day	8% 4 8% 29% 35% 16%	450
	11th to 20th	Day	13% 3 13% 30% 31% 10%	450
	21st to end	Day	8% 2 18% 30% 31% 10%	450
October	1st to 10th	Day	11% 6% 23% 33% 20% 6%	450
	11th to 20th	Day	11% 7% 22% 33% 21% 6%	450
	21st to end	Day	15% 10% 27% 28% 16% 4	456
November	1st to 10th	Day	19% 9% 26% 29% 14% 3	270
	11th to 20th	Day	15% 11% 41% 25% 7% 1	270
	21st to end	Day	14% 12% 36% 26% 11% 1	270
December	1st to 10th	Day	23% 16% 33% 21% 6% 1	270
	11th to 20th	Day	24% 21% 31% 21% 4	270
	21st to end	Day	25% 19% 27% 25% 4 1	297
January	1st to 10th	Night	22% 14% 34% 24% 5%	760
	11th to 20th	Night	19% 13% 30% 30% 8%	760
	21st to end	Night	23% 13% 37% 23% 3	836
February	1st to 10th	Night	19% 11% 32% 33% 6%	760
	11th to 20th	Night	23% 12% 35% 26% 5%	743
	21st to end	Night	18% 16% 38% 26% 3	628
March	1st to 10th	Night	16% 13% 35% 31% 6%	760
	11th to 20th	Night	15% 13% 35% 27% 10%	760
	21st to end	Night	14% 15% 31% 28% 11% 1	836
April	1st to 10th	Night	14% 9% 32% 30% 15% 1	598
	11th to 20th	Night	16% 8% 31% 28% 16% 2	533
	21st to end	Night	10% 7% 26% 35% 21% 1	540
May	1st to 10th	Night	7% 5% 25% 34% 25% 4	540
	11th to 20th	Night	8% 4 20% 35% 28% 5%	531
	21st to end	Night	9% 2 14% 33% 37% 6%	584
June	1st to 10th	Night	9% 1 12% 39% 34% 6%	540
	11th to 20th	Night	5% 3 10% 29% 38% 15%	540
	21st to end	Night	5% 2 7% 30% 46% 11%	540
July	1st to 10th	Night	6% 2 6% 25% 45% 16%	525
	11th to 20th	Night	5% 3 4 22% 47% 20%	522
	21st to end	Night	7% 1 5% 26% 48% 14%	591
August	1st to 10th	Night	6% 1 5% 27% 43% 19%	537
	11th to 20th	Night	11% 1 5% 25% 45% 13%	534
	21st to end	Night	14% 3 10% 25% 35% 13%	594
September	1st to 10th	Night	9% 2 10% 30% 39% 10%	645
	11th to 20th	Night	14% 2 14% 34% 32% 6%	720
	21st to end	Night	10% 1 17% 35% 34% 4	720
October	1st to 10th	Night	8% 4 25% 35% 24% 4	720
	11th to 20th	Night	11% 6% 24% 33% 22% 3	720
	21st to end	Night	14% 7% 24% 33% 20% 2	792
November	1st to 10th	Night	11% 6% 26% 35% 20% 2	740
	11th to 20th	Night	13% 11% 32% 30% 13% 1	760
	21st to end	Night	16% 9% 30% 32% 12% 1	760
December	1st to 10th	Night	19% 10% 29% 30% 11% 1	760
	11th to 20th	Night	21% 8% 33% 29% 8% 1	760
	21st to end	Night	25% 12% 27% 30% 6%	836

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