Puckett Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Puckett Observatory clear sky chart from 2005-11-06 to 2025-12-03.

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	15% 7% 3 6% 4 5% 5% 4 6% 8% 38%	126741
	Night	15% 7% 2 6% 4 4 4 3 5% 7% 42%	123984
Transparency	Day	42% 7% 11% 19% 16% 5%	130504
	Night	40% 6% 11% 20% 18% 5%	128289
Seeing	Day	20% 13% 24% 21% 15% 7%	16232
	Night	19% 10% 21% 27% 19% 3	26247

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	19% 10% 5% 4 2 3 2 2 4 4 44%	4056
	11th to 20th	Day	17% 5% 5% 7% 3 3 2 2 3 4 48%	4060
	21st to end	Day	22% 12% 3 5% 4 3 3 2 4 5% 38%	4627
February	1st to 10th	Day	20% 10% 3 6% 5% 3 3 3 5% 5% 36%	2000
	11th to 20th	Day	25% 9% 2 6% 4 4 4 3 5% 5% 35%	1948
	21st to end	Day	24% 8% 3 6% 4 3 3 2 5% 4 38%	1650
March	1st to 10th	Day	21% 8% 3 6% 4 5% 4 4 5% 5% 34%	4568
	11th to 20th	Day	13% 6% 2 6% 4 4 3 2 4 7% 50%	4980
	21st to end	Day	17% 8% 2 6% 4 4 4 3 4 6% 42%	5465
April	1st to 10th	Day	14% 7% 2 5% 5% 5% 5% 4 5% 7% 41%	2297
	11th to 20th	Day	13% 6% 3 6% 4 5% 5% 3 5% 6% 44%	2374
	21st to end	Day	13% 6% 2 6% 5% 4 5% 4 5% 8% 41%	2559
May	1st to 10th	Day	20% 7% 3 6% 4 4 5% 4 6% 7% 32%	5862
	11th to 20th	Day	19% 8% 3 9% 6% 5% 6% 5% 6% 8% 25%	5861
	21st to end	Day	16% 7% 2 7% 4 5% 4 4 6% 7% 36%	6433
June	1st to 10th	Day	13% 6% 2 8% 5% 6% 6% 5% 8% 8% 33%	2600
	11th to 20th	Day	7% 4 2 6% 6% 7% 6% 6% 9% 10% 37%	2600
	21st to end	Day	8% 5% 2 6% 7% 6% 6% 5% 9% 11% 35%	2600
July	1st to 10th	Day	7% 5% 2 6% 5% 6% 7% 6% 8% 11% 35%	5900
	11th to 20th	Day	8% 5% 2 7% 5% 7% 8% 6% 9% 14% 28%	5900
	21st to end	Day	11% 8% 3 9% 7% 7% 8% 6% 9% 10% 21%	6424
August	1st to 10th	Day	7% 3 2 6% 6% 5% 7% 6% 10% 12% 37%	4234
	11th to 20th	Day	9% 5% 2 6% 4 6% 6% 6% 8% 12% 37%	3917
	21st to end	Day	8% 4 2 6% 5% 6% 6% 5% 7% 8% 43%	4312
September	1st to 10th	Day	11% 6% 3 7% 6% 6% 6% 4 7% 10% 35%	2230
	11th to 20th	Day	14% 6% 2 7% 5% 4 5% 4 7% 8% 38%	2200
	21st to end	Day	14% 5% 2 6% 4 4 5% 4 5% 7% 43%	2200
October	1st to 10th	Day	10% 5% 2 6% 4 4 4 3 4 6% 52%	2200
	11th to 20th	Day	12% 4 2 4 3 3 3 3 4 5% 55%	2095
	21st to end	Day	14% 6% 2 4 2 3 3 3 5% 5% 53%	2170
November	1st to 10th	Day	13% 5% 2 4 3 3 3 3 5% 5% 54%	1852
	11th to 20th	Day	15% 6% 1 4 3 3 3 3 4 7% 50%	1890
	21st to end	Day	17% 8% 3 6% 3 3 4 3 5% 6% 44%	1890
December	1st to 10th	Day	22% 7% 2 4 3 3 4 3 4 4 45%	2948
	11th to 20th	Day	22% 10% 4 7% 4 4 3 2 4 4 36%	3373
	21st to end	Day	22% 9% 5% 5% 3 3 3 3 5% 6% 36%	4466
January	1st to 10th	Night	17% 12% 2 5% 4 3 3 2 3 5% 44%	5889
	11th to 20th	Night	19% 8% 3 6% 3 3 3 2 4 4 46%	5900
	21st to end	Night	18% 11% 3 5% 3 3 3 2 4 5% 43%	6324
February	1st to 10th	Night	18% 7% 3 6% 4 4 4 3 4 6% 41%	2400
	11th to 20th	Night	24% 8% 2 6% 4 4 4 3 5% 4 36%	2338
	21st to end	Night	23% 9% 3 6% 4 3 5% 3 4 5% 36%	1980
March	1st to 10th	Night	20% 10% 3 7% 4 4 4 3 5% 7% 33%	5284
	11th to 20th	Night	13% 5% 1 5% 4 3 4 4 6% 7% 49%	4980
	21st to end	Night	15% 8% 2 6% 4 4 3 3 4 6% 43%	5467
April	1st to 10th	Night	14% 4 1 4 4 4 4 4 5% 8% 46%	2118
	11th to 20th	Night	14% 7% 2 4 3 3 3 3 5% 7% 48%	1975
	21st to end	Night	12% 7% 2 6% 4 4 4 3 5% 8% 47%	1840
May	1st to 10th	Night	16% 7% 3 7% 5% 5% 5% 5% 6% 8% 33%	4033
	11th to 20th	Night	22% 8% 3 8% 5% 5% 5% 4 6% 7% 27%	4032
	21st to end	Night	14% 7% 3 5% 4 5% 5% 4 7% 9% 38%	4421
June	1st to 10th	Night	9% 6% 3 7% 6% 6% 6% 4 7% 11% 36%	1800
	11th to 20th	Night	7% 5% 1 4 4 4 5% 5% 9% 13% 44%	1800
	21st to end	Night	7% 5% 2 5% 5% 5% 6% 4 8% 11% 44%	1800
July	1st to 10th	Night	9% 6% 2 7% 5% 6% 6% 5% 7% 11% 37%	4058
	11th to 20th	Night	7% 6% 2 8% 5% 6% 6% 4 8% 11% 38%	4057
	21st to end	Night	12% 8% 3 8% 6% 6% 6% 5% 8% 10% 29%	4427
August	1st to 10th	Night	6% 4 2 6% 5% 4 5% 5% 7% 12% 43%	2915
	11th to 20th	Night	8% 6% 3 6% 4 5% 4 4 6% 8% 47%	3128
	21st to end	Night	7% 5% 2 5% 4 4 4 3 6% 9% 50%	3586
September	1st to 10th	Night	8% 6% 3 6% 6% 5% 5% 5% 7% 9% 40%	2148
	11th to 20th	Night	10% 7% 2 6% 4 4 5% 4 6% 8% 45%	2200
	21st to end	Night	12% 5% 3 5% 4 4 4 3 5% 6% 50%	2200
October	1st to 10th	Night	10% 4 2 5% 3 4 4 3 4 6% 56%	2200
	11th to 20th	Night	12% 5% 2 5% 3 3 4 2 3 5% 56%	2304
	21st to end	Night	13% 6% 1 5% 3 3 3 3 4 5% 54%	2665
November	1st to 10th	Night	12% 6% 2 5% 3 3 3 2 4 6% 53%	2666
	11th to 20th	Night	13% 6% 2 5% 3 3 3 3 4 6% 52%	2730
	21st to end	Night	17% 7% 2 5% 4 3 4 3 5% 6% 44%	2730
December	1st to 10th	Night	21% 7% 2 4 3 3 3 3 5% 5% 44%	4277
	11th to 20th	Night	22% 9% 3 6% 3 3 3 3 4 5% 39%	4822
	21st to end	Night	21% 9% 4 6% 4 4 4 3 4 6% 35%	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	46% 3 5% 18% 25% 4	4057
	11th to 20th	Day	41% 3 5% 15% 30% 5%	4060
	21st to end	Day	50% 3 6% 16% 20% 6%	4627
February	1st to 10th	Day	49% 4 6% 19% 18% 3	2000
	11th to 20th	Day	52% 4 6% 16% 17% 5%	1958
	21st to end	Day	50% 4 6% 13% 21% 6%	1650
March	1st to 10th	Day	49% 5% 7% 12% 18% 8%	4568
	11th to 20th	Day	35% 4 6% 16% 23% 15%	4980
	21st to end	Day	44% 4 7% 25% 17% 3	5465
April	1st to 10th	Day	41% 7% 11% 19% 17% 4	2297
	11th to 20th	Day	40% 5% 8% 18% 24% 5%	2374
	21st to end	Day	39% 7% 11% 26% 14% 3	2559
May	1st to 10th	Day	48% 8% 13% 19% 10% 1	5897
	11th to 20th	Day	55% 9% 12% 18% 6% 1	5865
	21st to end	Day	44% 8% 10% 21% 15% 2	6447
June	1st to 10th	Day	45% 10% 15% 20% 9% 1	2600
	11th to 20th	Day	36% 12% 16% 22% 11% 2	2600
	21st to end	Day	37% 12% 17% 19% 12% 2	2600
July	1st to 10th	Day	36% 13% 21% 21% 9% 1	5835
	11th to 20th	Day	39% 15% 27% 14% 4 1	5831
	21st to end	Day	52% 13% 16% 14% 4	6240
August	1st to 10th	Day	34% 12% 17% 28% 9%	4221
	11th to 20th	Day	34% 11% 20% 21% 13% 1	3955
	21st to end	Day	35% 10% 13% 26% 15% 2	4311
September	1st to 10th	Day	42% 10% 12% 16% 16% 4	2230
	11th to 20th	Day	41% 9% 13% 19% 17% 1	2200
	21st to end	Day	39% 7% 13% 15% 20% 6%	2200
October	1st to 10th	Day	25% 6% 6% 16% 36% 11%	3590
	11th to 20th	Day	22% 4 5% 18% 28% 23%	3387
	21st to end	Day	27% 4 6% 25% 25% 12%	3484
November	1st to 10th	Day	32% 5% 7% 16% 30% 10%	1852
	11th to 20th	Day	35% 3 7% 20% 25% 10%	1890
	21st to end	Day	41% 5% 6% 18% 25% 5%	1890
December	1st to 10th	Day	43% 4 5% 16% 26% 6%	2948
	11th to 20th	Day	52% 4 6% 16% 18% 4	3370
	21st to end	Day	48% 3 9% 24% 13% 2	4466
January	1st to 10th	Night	45% 3 6% 16% 26% 4	5889
	11th to 20th	Night	43% 3 6% 18% 23% 8%	5900
	21st to end	Night	46% 2 5% 17% 23% 6%	6324
February	1st to 10th	Night	45% 4 8% 18% 21% 5%	2400
	11th to 20th	Night	52% 4 6% 15% 17% 6%	2339
	21st to end	Night	51% 3 8% 14% 18% 6%	1980
March	1st to 10th	Night	51% 5% 7% 13% 20% 4	5284
	11th to 20th	Night	33% 5% 7% 18% 21% 15%	4980
	21st to end	Night	42% 4 8% 24% 17% 5%	5467
April	1st to 10th	Night	35% 6% 12% 20% 22% 5%	2118
	11th to 20th	Night	36% 4 9% 22% 21% 8%	1975
	21st to end	Night	37% 5% 12% 26% 17% 2	1840
May	1st to 10th	Night	46% 9% 15% 18% 11% 1	4060
	11th to 20th	Night	54% 7% 15% 16% 7%	4033
	21st to end	Night	39% 10% 13% 24% 13% 1	4429
June	1st to 10th	Night	41% 10% 16% 21% 11% 2	1800
	11th to 20th	Night	28% 12% 21% 26% 12% 2	1800
	21st to end	Night	32% 12% 19% 20% 13% 4	1800
July	1st to 10th	Night	37% 12% 20% 24% 7%	4015
	11th to 20th	Night	37% 13% 26% 18% 4 1	4006
	21st to end	Night	47% 13% 17% 17% 5% 1	4297
August	1st to 10th	Night	30% 11% 18% 31% 9%	2904
	11th to 20th	Night	33% 8% 18% 26% 14%	3156
	21st to end	Night	29% 9% 14% 27% 20% 2	3586
September	1st to 10th	Night	37% 11% 14% 18% 15% 5%	2148
	11th to 20th	Night	34% 11% 15% 21% 18% 1	2200
	21st to end	Night	34% 8% 12% 20% 19% 7%	2200
October	1st to 10th	Night	21% 5% 9% 17% 35% 13%	3590
	11th to 20th	Night	20% 3 6% 17% 34% 20%	3751
	21st to end	Night	23% 4 5% 28% 28% 13%	4301
November	1st to 10th	Night	32% 5% 9% 20% 25% 9%	2666
	11th to 20th	Night	34% 3 6% 19% 26% 10%	2730
	21st to end	Night	41% 5% 6% 20% 23% 6%	2730
December	1st to 10th	Night	43% 4 6% 16% 25% 6%	4277
	11th to 20th	Night	48% 5% 7% 15% 21% 4	4824
	21st to end	Night	50% 5% 9% 23% 13% 1	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	35% 26% 30% 7% 1	300
	11th to 20th	Day	38% 22% 27% 10% 2	300
	21st to end	Day	28% 33% 28% 9% 2	330
February	1st to 10th	Day	34% 21% 34% 10% 1	300
	11th to 20th	Day	49% 21% 24% 5% 1	300
	21st to end	Day	44% 23% 24% 7% 1	249
March	1st to 10th	Day	34% 21% 29% 12% 3 1	336
	11th to 20th	Day	31% 21% 27% 16% 4 1	500
	21st to end	Day	27% 23% 29% 15% 5%	550
April	1st to 10th	Day	28% 16% 27% 18% 10% 1	500
	11th to 20th	Day	19% 19% 31% 21% 9% 1	492
	21st to end	Day	22% 13% 32% 19% 11% 3	500
May	1st to 10th	Day	22% 15% 30% 19% 10% 5%	503
	11th to 20th	Day	17% 12% 28% 24% 13% 7%	527
	21st to end	Day	16% 10% 23% 25% 16% 10%	573
June	1st to 10th	Day	15% 8% 23% 26% 19% 10%	530
	11th to 20th	Day	10% 5% 18% 29% 24% 14%	530
	21st to end	Day	9% 5% 23% 26% 22% 15%	530
July	1st to 10th	Day	11% 4 12% 30% 26% 17%	525
	11th to 20th	Day	10% 4 12% 27% 27% 19%	524
	21st to end	Day	10% 5% 10% 27% 28% 20%	576
August	1st to 10th	Day	13% 4 17% 24% 24% 19%	526
	11th to 20th	Day	13% 4 17% 26% 26% 14%	519
	21st to end	Day	14% 4 14% 23% 30% 15%	583
September	1st to 10th	Day	10% 2 22% 28% 27% 11%	530
	11th to 20th	Day	15% 6% 16% 27% 28% 8%	530
	21st to end	Day	16% 6% 19% 29% 25% 5%	530
October	1st to 10th	Day	14% 7% 26% 30% 17% 6%	530
	11th to 20th	Day	18% 10% 25% 28% 17% 2	530
	21st to end	Day	20% 12% 29% 24% 13% 2	553
November	1st to 10th	Day	21% 16% 33% 22% 6% 2	330
	11th to 20th	Day	24% 19% 36% 18% 3	330
	21st to end	Day	22% 26% 32% 14% 4 1	330
December	1st to 10th	Day	34% 24% 24% 16% 1 1	306
	11th to 20th	Day	31% 19% 32% 13% 4	300
	21st to end	Day	33% 21% 32% 12% 3	330
January	1st to 10th	Night	31% 19% 28% 18% 4	800
	11th to 20th	Night	29% 17% 25% 22% 7%	800
	21st to end	Night	25% 18% 30% 24% 2	880
February	1st to 10th	Night	26% 14% 27% 28% 5%	800
	11th to 20th	Night	32% 20% 27% 20% 2	783
	21st to end	Night	31% 18% 29% 19% 2	660
March	1st to 10th	Night	23% 19% 29% 25% 5%	800
	11th to 20th	Night	23% 17% 27% 26% 7% 1	800
	21st to end	Night	23% 16% 29% 25% 8%	880
April	1st to 10th	Night	18% 16% 25% 29% 10% 1	718
	11th to 20th	Night	18% 15% 28% 26% 12% 1	593
	21st to end	Night	17% 9% 25% 33% 15% 1	600
May	1st to 10th	Night	14% 9% 26% 32% 18% 2	600
	11th to 20th	Night	16% 7% 21% 32% 20% 5%	591
	21st to end	Night	14% 3 16% 31% 30% 6%	650
June	1st to 10th	Night	11% 3 13% 36% 32% 5%	600
	11th to 20th	Night	9% 2 11% 29% 38% 11%	600
	21st to end	Night	7% 2 9% 31% 43% 9%	600
July	1st to 10th	Night	11% 2 8% 23% 47% 10%	585
	11th to 20th	Night	9% 1 8% 24% 43% 14%	582
	21st to end	Night	11% 2 6% 23% 49% 9%	657
August	1st to 10th	Night	9% 2 8% 27% 42% 12%	597
	11th to 20th	Night	9% 3 12% 26% 40% 9%	594
	21st to end	Night	13% 2 12% 23% 41% 9%	660
September	1st to 10th	Night	10% 2 13% 28% 39% 8%	748
	11th to 20th	Night	12% 3 15% 32% 34% 4	800
	21st to end	Night	13% 5% 15% 34% 31% 2	800
October	1st to 10th	Night	11% 7% 21% 32% 22% 6%	800
	11th to 20th	Night	14% 9% 28% 29% 19% 2	800
	21st to end	Night	17% 10% 21% 33% 16% 2	880
November	1st to 10th	Night	17% 7% 25% 30% 17% 3	820
	11th to 20th	Night	18% 15% 24% 29% 11% 1	840
	21st to end	Night	22% 15% 27% 25% 11% 1	840
December	1st to 10th	Night	29% 17% 23% 24% 7% 1	809
	11th to 20th	Night	26% 13% 25% 27% 7% 1	800
	21st to end	Night	31% 13% 25% 25% 6%	880

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