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 2025-08-05.

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	12% 6% 2 6% 4 5% 5% 4 6% 8% 42%	125467
	Night	13% 6% 2 6% 4 4 4 4 6% 8% 44%	122615
Transparency	Day	37% 7% 12% 19% 18% 7%	129280
	Night	37% 6% 11% 19% 20% 8%	126858
Seeing	Day	14% 9% 22% 25% 20% 10%	15731
	Night	14% 7% 24% 30% 21% 4	25703

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	16% 9% 2 5% 3 3 3 3 4 5% 49%	4056
	11th to 20th	Day	12% 7% 3 4 3 3 4 3 5% 6% 51%	4085
	21st to end	Day	23% 10% 3 6% 3 3 3 2 4 5% 39%	4972
February	1st to 10th	Day	17% 8% 3 6% 5% 5% 4 3 5% 6% 39%	2000
	11th to 20th	Day	20% 7% 3 6% 3 3 4 3 4 5% 42%	1948
	21st to end	Day	15% 8% 3 7% 4 4 4 3 4 7% 40%	1650
March	1st to 10th	Day	20% 7% 2 7% 4 4 4 4 6% 5% 37%	4480
	11th to 20th	Day	11% 5% 2 5% 4 4 5% 4 5% 6% 51%	4975
	21st to end	Day	17% 6% 2 6% 4 4 4 3 5% 6% 43%	5465
April	1st to 10th	Day	13% 5% 2 6% 4 4 4 4 6% 7% 45%	2360
	11th to 20th	Day	11% 5% 2 6% 4 4 4 3 5% 7% 47%	2374
	21st to end	Day	8% 4 2 5% 4 4 4 4 6% 8% 51%	2436
May	1st to 10th	Day	12% 6% 3 8% 5% 5% 5% 4 6% 8% 38%	5862
	11th to 20th	Day	16% 6% 2 6% 4 5% 5% 4 7% 9% 35%	5861
	21st to end	Day	9% 5% 2 6% 4 5% 5% 4 6% 9% 44%	6433
June	1st to 10th	Day	9% 7% 2 8% 6% 6% 6% 6% 9% 10% 32%	2600
	11th to 20th	Day	6% 3 1 5% 6% 6% 6% 6% 9% 11% 41%	2600
	21st to end	Day	6% 5% 2 7% 6% 7% 7% 5% 9% 11% 34%	2600
July	1st to 10th	Day	9% 5% 2 7% 6% 6% 7% 7% 9% 12% 31%	5900
	11th to 20th	Day	6% 4 2 7% 6% 7% 7% 6% 9% 12% 34%	5900
	21st to end	Day	8% 5% 2 7% 7% 8% 8% 7% 11% 13% 25%	6424
August	1st to 10th	Day	5% 3 1 5% 5% 6% 6% 5% 9% 14% 41%	3899
	11th to 20th	Day	8% 5% 2 6% 4 5% 5% 4 6% 9% 48%	3729
	21st to end	Day	7% 5% 2 4 4 5% 5% 5% 8% 10% 46%	4180
September	1st to 10th	Day	10% 6% 3 8% 5% 7% 7% 5% 6% 8% 36%	2148
	11th to 20th	Day	14% 6% 2 7% 4 5% 6% 4 6% 7% 40%	2090
	21st to end	Day	11% 5% 2 6% 5% 4 5% 4 5% 6% 49%	2090
October	1st to 10th	Day	10% 6% 2 5% 4 3 3 4 4 6% 54%	2090
	11th to 20th	Day	10% 4 2 4 3 3 3 4 5% 7% 57%	2081
	21st to end	Day	12% 5% 2 4 3 3 3 3 4 5% 56%	2048
November	1st to 10th	Day	11% 6% 2 4 4 4 4 3 4 5% 53%	1762
	11th to 20th	Day	13% 5% 1 4 3 2 4 2 4 6% 56%	1800
	21st to end	Day	14% 5% 2 5% 4 4 5% 3 5% 6% 47%	1800
December	1st to 10th	Day	18% 5% 2 5% 3 3 4 3 4 6% 48%	2930
	11th to 20th	Day	14% 7% 3 5% 4 4 4 3 5% 6% 46%	3373
	21st to end	Day	21% 7% 2 6% 4 4 3 3 4 5% 41%	4466
January	1st to 10th	Night	16% 8% 3 5% 3 3 3 3 4 5% 48%	5889
	11th to 20th	Night	14% 7% 3 7% 4 4 4 3 4 5% 45%	5872
	21st to end	Night	19% 10% 2 5% 3 3 3 3 4 6% 41%	5984
February	1st to 10th	Night	15% 8% 3 6% 5% 3 3 3 4 6% 43%	2400
	11th to 20th	Night	20% 7% 2 6% 4 3 3 3 4 5% 43%	2338
	21st to end	Night	15% 7% 3 6% 4 4 4 3 5% 7% 43%	1980
March	1st to 10th	Night	21% 9% 3 6% 4 3 4 3 5% 6% 36%	5373
	11th to 20th	Night	12% 6% 2 5% 4 4 4 3 5% 6% 49%	4985
	21st to end	Night	12% 6% 2 6% 4 4 4 4 5% 7% 46%	5467
April	1st to 10th	Night	12% 5% 2 5% 5% 3 4 4 6% 7% 46%	2055
	11th to 20th	Night	12% 5% 2 5% 3 3 3 3 6% 9% 49%	1975
	21st to end	Night	7% 5% 2 5% 3 4 5% 3 4 7% 54%	1960
May	1st to 10th	Night	12% 5% 3 6% 5% 4 5% 4 7% 9% 40%	4033
	11th to 20th	Night	17% 7% 2 7% 4 4 5% 4 6% 7% 36%	4032
	21st to end	Night	8% 5% 2 5% 4 4 5% 5% 7% 11% 44%	4421
June	1st to 10th	Night	7% 6% 2 8% 6% 6% 6% 5% 8% 11% 34%	1800
	11th to 20th	Night	5% 4 2 5% 4 5% 6% 5% 8% 11% 44%	1800
	21st to end	Night	5% 5% 2 6% 6% 5% 5% 6% 8% 13% 39%	1800
July	1st to 10th	Night	10% 6% 3 7% 6% 6% 7% 6% 8% 12% 29%	4058
	11th to 20th	Night	5% 4 2 6% 5% 6% 6% 6% 10% 14% 36%	4057
	21st to end	Night	9% 6% 3 8% 6% 6% 7% 6% 8% 13% 28%	4427
August	1st to 10th	Night	5% 4 2 7% 4 5% 6% 6% 8% 13% 39%	3112
	11th to 20th	Night	7% 4 2 5% 4 4 5% 4 7% 11% 48%	3100
	21st to end	Night	7% 5% 2 5% 3 4 4 4 6% 10% 52%	3476
September	1st to 10th	Night	9% 6% 2 6% 5% 4 5% 6% 7% 9% 42%	2011
	11th to 20th	Night	13% 7% 3 6% 4 4 5% 4 6% 7% 43%	2090
	21st to end	Night	9% 5% 2 6% 4 4 4 3 5% 7% 50%	2090
October	1st to 10th	Night	8% 4 2 5% 3 3 3 3 5% 6% 57%	2090
	11th to 20th	Night	9% 4 1 5% 3 2 3 3 4 6% 59%	2096
	21st to end	Night	11% 5% 2 4 3 3 3 2 3 4 59%	2546
November	1st to 10th	Night	10% 4 2 5% 3 3 4 4 4 5% 56%	2536
	11th to 20th	Night	12% 5% 2 5% 3 3 3 3 4 5% 55%	2600
	21st to end	Night	13% 6% 2 6% 3 3 3 3 4 6% 50%	2600
December	1st to 10th	Night	17% 5% 2 5% 3 3 3 2 4 6% 52%	4250
	11th to 20th	Night	15% 5% 2 6% 4 3 3 3 5% 7% 48%	4822
	21st to end	Night	20% 6% 2 6% 4 3 4 3 4 6% 42%	6490

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	39% 3 5% 20% 28% 6%	4057
	11th to 20th	Day	34% 3 4 18% 32% 8%	4085
	21st to end	Day	48% 3 8% 11% 18% 11%	4972
February	1st to 10th	Day	46% 4 7% 16% 19% 7%	2000
	11th to 20th	Day	44% 5% 5% 16% 22% 8%	1958
	21st to end	Day	43% 5% 7% 16% 18% 10%	1650
March	1st to 10th	Day	47% 6% 7% 13% 21% 7%	4480
	11th to 20th	Day	33% 5% 7% 13% 21% 20%	4975
	21st to end	Day	41% 5% 9% 17% 19% 10%	5465
April	1st to 10th	Day	36% 6% 10% 21% 17% 10%	2360
	11th to 20th	Day	35% 5% 8% 18% 25% 9%	2374
	21st to end	Day	30% 7% 11% 22% 26% 5%	2436
May	1st to 10th	Day	41% 7% 13% 21% 16% 2	5897
	11th to 20th	Day	42% 8% 19% 21% 9% 1	5865
	21st to end	Day	34% 8% 14% 23% 20% 1	6447
June	1st to 10th	Day	41% 11% 15% 19% 11% 2	2600
	11th to 20th	Day	32% 11% 18% 23% 14% 2	2600
	21st to end	Day	38% 13% 17% 20% 10% 3	2600
July	1st to 10th	Day	41% 13% 23% 19% 4 1	5835
	11th to 20th	Day	37% 12% 30% 18% 3	5831
	21st to end	Day	45% 14% 23% 16% 3	6240
August	1st to 10th	Day	30% 11% 16% 29% 14% 1	3886
	11th to 20th	Day	31% 9% 15% 28% 16% 1	3765
	21st to end	Day	29% 10% 18% 26% 15% 3	4179
September	1st to 10th	Day	42% 10% 12% 16% 15% 5%	2148
	11th to 20th	Day	41% 9% 10% 17% 18% 4	2090
	21st to end	Day	35% 7% 9% 21% 21% 7%	2090
October	1st to 10th	Day	27% 4 7% 13% 27% 22%	3480
	11th to 20th	Day	16% 3 4 16% 26% 34%	3437
	21st to end	Day	20% 3 5% 18% 42% 13%	3350
November	1st to 10th	Day	35% 4 6% 15% 27% 13%	1762
	11th to 20th	Day	31% 3 7% 16% 26% 16%	1800
	21st to end	Day	37% 5% 8% 16% 25% 9%	1800
December	1st to 10th	Day	37% 4 6% 18% 26% 8%	2930
	11th to 20th	Day	40% 3 9% 18% 22% 7%	3370
	21st to end	Day	44% 4 6% 22% 21% 3	4466
January	1st to 10th	Night	39% 3 4 19% 28% 6%	5889
	11th to 20th	Night	41% 3 5% 18% 24% 10%	5872
	21st to end	Night	45% 3 6% 14% 24% 8%	5984
February	1st to 10th	Night	42% 4 7% 18% 19% 11%	2400
	11th to 20th	Night	43% 5% 5% 14% 22% 11%	2339
	21st to end	Night	40% 5% 8% 17% 16% 14%	1980
March	1st to 10th	Night	48% 5% 6% 14% 17% 10%	5373
	11th to 20th	Night	34% 5% 8% 13% 21% 19%	4985
	21st to end	Night	37% 5% 8% 19% 21% 11%	5467
April	1st to 10th	Night	35% 7% 10% 18% 19% 11%	2055
	11th to 20th	Night	31% 5% 7% 22% 25% 11%	1975
	21st to end	Night	29% 5% 12% 23% 23% 8%	1960
May	1st to 10th	Night	36% 9% 16% 21% 15% 3	4060
	11th to 20th	Night	45% 7% 15% 22% 9% 2	4033
	21st to end	Night	31% 8% 15% 26% 18% 2	4429
June	1st to 10th	Night	41% 11% 17% 15% 15% 1	1800
	11th to 20th	Night	29% 10% 20% 24% 14% 2	1800
	21st to end	Night	33% 11% 20% 20% 12% 4	1800
July	1st to 10th	Night	44% 12% 23% 16% 4 1	4015
	11th to 20th	Night	34% 13% 30% 18% 4	4006
	21st to end	Night	46% 12% 23% 17% 3	4297
August	1st to 10th	Night	34% 9% 17% 28% 11% 1	3101
	11th to 20th	Night	29% 8% 18% 28% 15% 2	3130
	21st to end	Night	28% 7% 18% 26% 19% 2	3476
September	1st to 10th	Night	36% 11% 16% 17% 15% 6%	2011
	11th to 20th	Night	38% 8% 13% 18% 16% 5%	2090
	21st to end	Night	34% 7% 9% 20% 21% 8%	2090
October	1st to 10th	Night	31% 4 8% 13% 25% 19%	3480
	11th to 20th	Night	16% 3 4 13% 30% 33%	3479
	21st to end	Night	21% 2 4 19% 35% 18%	4182
November	1st to 10th	Night	31% 4 8% 16% 25% 15%	2536
	11th to 20th	Night	32% 3 5% 17% 27% 16%	2600
	21st to end	Night	37% 4 8% 16% 23% 12%	2600
December	1st to 10th	Night	36% 3 6% 20% 27% 9%	4250
	11th to 20th	Night	37% 3 10% 19% 23% 7%	4824
	21st to end	Night	43% 4 6% 20% 24% 3	6490

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% 36% 17% 3	300
	11th to 20th	Day	16% 24% 35% 18% 7% 1	300
	21st to end	Day	24% 22% 38% 13% 2 1	330
February	1st to 10th	Day	25% 19% 37% 15% 5%	300
	11th to 20th	Day	29% 22% 33% 14% 2	300
	21st to end	Day	20% 23% 42% 12% 2	249
March	1st to 10th	Day	23% 19% 36% 19% 3 1	300
	11th to 20th	Day	20% 17% 33% 22% 7% 1	495
	21st to end	Day	21% 16% 33% 23% 7% 1	550
April	1st to 10th	Day	19% 16% 28% 26% 10% 2	500
	11th to 20th	Day	13% 13% 34% 23% 14% 2	492
	21st to end	Day	12% 9% 25% 34% 18% 3	500
May	1st to 10th	Day	11% 9% 27% 28% 19% 6%	503
	11th to 20th	Day	12% 4 24% 29% 22% 10%	527
	21st to end	Day	12% 4 18% 31% 23% 12%	573
June	1st to 10th	Day	12% 3 15% 31% 27% 12%	530
	11th to 20th	Day	7% 2 15% 24% 30% 22%	530
	21st to end	Day	7% 3 13% 26% 28% 22%	530
July	1st to 10th	Day	8% 2 7% 22% 35% 25%	525
	11th to 20th	Day	6% 2 6% 18% 37% 31%	524
	21st to end	Day	7% 2 6% 22% 37% 27%	576
August	1st to 10th	Day	8% 1 8% 23% 34% 25%	502
	11th to 20th	Day	10% 2 6% 22% 38% 23%	479
	21st to end	Day	13% 2 9% 27% 31% 18%	539
September	1st to 10th	Day	10% 4 9% 29% 33% 15%	490
	11th to 20th	Day	15% 3 13% 30% 31% 9%	490
	21st to end	Day	9% 2 18% 29% 31% 10%	490
October	1st to 10th	Day	11% 7% 24% 32% 20% 6%	490
	11th to 20th	Day	10% 7% 24% 33% 20% 6%	490
	21st to end	Day	14% 9% 26% 29% 18% 4	497
November	1st to 10th	Day	19% 9% 27% 29% 13% 3	300
	11th to 20th	Day	15% 10% 40% 26% 8% 1	300
	21st to end	Day	14% 13% 36% 26% 10% 1	300
December	1st to 10th	Day	23% 15% 35% 20% 6% 1	300
	11th to 20th	Day	23% 19% 32% 22% 4	300
	21st to end	Day	23% 18% 27% 25% 5% 1	330
January	1st to 10th	Night	22% 15% 35% 24% 5%	800
	11th to 20th	Night	20% 13% 31% 29% 8%	800
	21st to end	Night	22% 13% 38% 23% 4	880
February	1st to 10th	Night	19% 10% 32% 34% 6%	800
	11th to 20th	Night	23% 13% 34% 25% 5%	783
	21st to end	Night	17% 16% 38% 27% 3	660
March	1st to 10th	Night	16% 13% 35% 30% 5%	800
	11th to 20th	Night	15% 13% 34% 28% 10%	800
	21st to end	Night	14% 15% 31% 29% 10% 1	880
April	1st to 10th	Night	15% 10% 32% 30% 13%	655
	11th to 20th	Night	15% 8% 31% 31% 15% 2	593
	21st to end	Night	9% 7% 26% 37% 21% 1	600
May	1st to 10th	Night	8% 5% 24% 35% 24% 4	600
	11th to 20th	Night	10% 4 20% 35% 25% 5%	591
	21st to end	Night	8% 3 14% 35% 34% 5%	650
June	1st to 10th	Night	9% 2 12% 38% 34% 5%	600
	11th to 20th	Night	5% 3 10% 30% 38% 14%	600
	21st to end	Night	5% 2 7% 30% 46% 11%	600
July	1st to 10th	Night	7% 2 6% 24% 44% 16%	585
	11th to 20th	Night	5% 3 4 21% 48% 20%	582
	21st to end	Night	7% 1 5% 25% 49% 14%	657
August	1st to 10th	Night	6% 1 6% 26% 43% 18%	579
	11th to 20th	Night	10% 1 5% 26% 45% 12%	564
	21st to end	Night	13% 2 11% 26% 35% 13%	627
September	1st to 10th	Night	11% 2 10% 30% 38% 10%	681
	11th to 20th	Night	16% 2 13% 33% 31% 5%	760
	21st to end	Night	11% 1 17% 34% 33% 4	760
October	1st to 10th	Night	8% 4 24% 35% 24% 4	760
	11th to 20th	Night	11% 6% 24% 34% 22% 3	760
	21st to end	Night	13% 7% 23% 34% 21% 2	836
November	1st to 10th	Night	12% 6% 26% 34% 20% 2	780
	11th to 20th	Night	14% 10% 32% 30% 14% 1	800
	21st to end	Night	16% 9% 31% 31% 12% 1	800
December	1st to 10th	Night	19% 10% 30% 31% 10% 1	800
	11th to 20th	Night	21% 8% 33% 29% 8% 1	800
	21st to end	Night	25% 11% 28% 30% 6%	880

Page generated at 2025-08-02 00:32:28. Version ac07

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