Cullman County Rd
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Cullman County Rd clear sky chart from 2005-11-06 to 2026-02-01.

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 6% 4 4 5% 4 6% 8% 41%	127263
	Night	14% 6% 2 6% 4 4 4 3 5% 7% 44%	124792
Transparency	Day	40% 4 11% 22% 18% 5%	131019
	Night	39% 3 9% 22% 20% 7%	129095
Seeing	Day	17% 10% 22% 23% 18% 9%	16065
	Night	16% 8% 21% 30% 21% 4	26100

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% 9% 5% 5% 3 3 2 3 4 5% 43%	4146
	11th to 20th	Day	14% 6% 5% 6% 3 2 2 2 3 4 52%	4356
	21st to end	Day	22% 10% 3 6% 3 3 3 3 4 6% 39%	5082
February	1st to 10th	Day	20% 9% 2 5% 4 3 3 3 4 6% 40%	2000
	11th to 20th	Day	24% 8% 3 5% 4 3 3 3 4 5% 39%	1948
	21st to end	Day	22% 9% 2 6% 3 4 3 3 4 5% 39%	1650
March	1st to 10th	Day	22% 8% 3 7% 4 4 4 3 4 5% 36%	4480
	11th to 20th	Day	13% 6% 2 6% 4 4 4 4 5% 6% 46%	4741
	21st to end	Day	15% 6% 3 7% 4 4 4 3 5% 7% 42%	5816
April	1st to 10th	Day	12% 6% 2 6% 4 4 4 4 5% 6% 47%	2400
	11th to 20th	Day	14% 6% 2 6% 4 4 4 3 4 7% 47%	2374
	21st to end	Day	9% 6% 2 6% 5% 4 4 4 6% 8% 46%	2400
May	1st to 10th	Day	16% 7% 2 7% 5% 5% 6% 5% 7% 8% 33%	5761
	11th to 20th	Day	17% 7% 3 7% 5% 5% 6% 4 7% 8% 30%	5861
	21st to end	Day	13% 6% 2 7% 5% 5% 5% 4 6% 8% 40%	6433
June	1st to 10th	Day	10% 6% 2 6% 5% 6% 7% 5% 7% 9% 36%	2600
	11th to 20th	Day	6% 5% 2 6% 5% 5% 6% 6% 7% 10% 42%	2600
	21st to end	Day	7% 5% 2 6% 5% 5% 6% 5% 8% 9% 42%	2600
July	1st to 10th	Day	6% 5% 2 7% 6% 6% 6% 6% 8% 12% 35%	5900
	11th to 20th	Day	7% 5% 2 6% 5% 6% 7% 7% 10% 15% 32%	5900
	21st to end	Day	10% 7% 3 8% 6% 7% 8% 6% 9% 12% 25%	6253
August	1st to 10th	Day	4 3 1 4 4 5% 5% 4 8% 9% 53%	3905
	11th to 20th	Day	6% 4 2 6% 5% 5% 5% 4 7% 9% 46%	3849
	21st to end	Day	7% 4 2 5% 4 5% 4 4 5% 7% 51%	4312
September	1st to 10th	Day	10% 5% 3 7% 4 5% 5% 4 6% 9% 42%	2369
	11th to 20th	Day	12% 6% 2 6% 4 5% 6% 3 6% 7% 42%	2200
	21st to end	Day	10% 5% 2 5% 4 4 4 4 6% 6% 51%	2200
October	1st to 10th	Day	10% 5% 1 5% 3 3 3 3 5% 6% 54%	2200
	11th to 20th	Day	9% 4 2 5% 3 3 4 3 4 6% 57%	2188
	21st to end	Day	14% 5% 2 5% 3 4 3 3 4 5% 53%	2059
November	1st to 10th	Day	13% 5% 2 4 4 4 3 3 4 5% 53%	1852
	11th to 20th	Day	13% 5% 2 5% 3 3 4 3 4 6% 53%	1890
	21st to end	Day	16% 6% 2 5% 3 3 3 4 5% 7% 46%	1890
December	1st to 10th	Day	21% 9% 2 5% 3 3 3 3 4 5% 43%	3020
	11th to 20th	Day	20% 8% 3 8% 4 4 3 2 3 4 41%	3463
	21st to end	Day	21% 8% 3 6% 4 3 3 2 4 6% 39%	4565
January	1st to 10th	Night	17% 9% 3 6% 3 3 3 3 4 5% 42%	6019
	11th to 20th	Night	18% 8% 4 5% 3 2 3 2 3 5% 46%	5818
	21st to end	Night	20% 10% 2 5% 3 3 3 2 4 4 43%	6116
February	1st to 10th	Night	19% 8% 3 6% 3 3 3 2 4 5% 43%	2401
	11th to 20th	Night	22% 7% 3 7% 4 3 3 2 4 4 41%	2338
	21st to end	Night	21% 6% 2 5% 3 4 4 4 5% 6% 40%	1980
March	1st to 10th	Night	23% 9% 3 6% 5% 4 4 3 5% 5% 34%	5373
	11th to 20th	Night	13% 6% 2 5% 3 3 3 3 5% 7% 50%	5217
	21st to end	Night	16% 7% 3 8% 5% 3 3 3 3 5% 44%	5155
April	1st to 10th	Night	11% 6% 2 5% 4 4 4 4 6% 8% 47%	2000
	11th to 20th	Night	13% 5% 2 5% 3 4 4 3 4 7% 50%	1975
	21st to end	Night	11% 5% 1 6% 4 4 3 3 6% 7% 50%	2000
May	1st to 10th	Night	13% 7% 3 7% 5% 5% 5% 4 6% 8% 37%	4132
	11th to 20th	Night	17% 8% 3 8% 6% 5% 5% 4 6% 6% 31%	4032
	21st to end	Night	12% 6% 3 6% 4 4 5% 4 6% 10% 40%	4421
June	1st to 10th	Night	6% 5% 3 5% 6% 6% 4 5% 8% 9% 43%	1800
	11th to 20th	Night	6% 2 2 4 3 4 5% 5% 6% 11% 52%	1800
	21st to end	Night	6% 4 2 6% 6% 5% 5% 4 8% 10% 45%	1800
July	1st to 10th	Night	8% 5% 2 7% 6% 6% 6% 5% 7% 10% 39%	4058
	11th to 20th	Night	8% 4 2 5% 5% 5% 6% 6% 9% 14% 35%	4057
	21st to end	Night	9% 7% 3 8% 6% 7% 8% 6% 9% 11% 27%	4580
August	1st to 10th	Night	3 2 1 4 3 4 5% 4 6% 10% 58%	3244
	11th to 20th	Night	5% 3 1 4 4 4 4 5% 6% 10% 54%	3200
	21st to end	Night	6% 4 2 4 4 3 5% 4 6% 7% 56%	3586
September	1st to 10th	Night	8% 5% 3 5% 5% 4 5% 4 6% 8% 47%	2010
	11th to 20th	Night	12% 6% 2 6% 4 4 4 3 6% 8% 45%	2200
	21st to end	Night	7% 6% 2 6% 4 4 3 3 6% 6% 54%	2200
October	1st to 10th	Night	9% 5% 1 5% 3 3 3 3 3 5% 61%	2200
	11th to 20th	Night	11% 4 2 4 4 3 3 3 4 5% 58%	2209
	21st to end	Night	16% 5% 2 4 3 3 3 2 3 4 56%	2780
November	1st to 10th	Night	11% 4 2 5% 4 3 3 3 4 5% 55%	2666
	11th to 20th	Night	13% 6% 2 4 3 2 3 3 4 5% 55%	2730
	21st to end	Night	15% 6% 2 5% 3 4 4 3 4 6% 47%	2730
December	1st to 10th	Night	22% 5% 2 4 3 2 3 3 4 5% 47%	4380
	11th to 20th	Night	21% 8% 2 6% 4 3 3 3 3 4 44%	4952
	21st to end	Night	22% 7% 3 6% 3 4 3 3 5% 6% 38%	6633

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% 1 4 26% 20% 3	4147
	11th to 20th	Day	39% 2 4 25% 28% 3	4356
	21st to end	Day	49% 2 5% 17% 21% 6%	5082
February	1st to 10th	Day	47% 2 6% 20% 20% 4	2000
	11th to 20th	Day	49% 2 4 19% 19% 6%	1958
	21st to end	Day	49% 2 5% 14% 23% 6%	1650
March	1st to 10th	Day	52% 2 7% 14% 18% 8%	4480
	11th to 20th	Day	39% 2 6% 18% 21% 14%	4741
	21st to end	Day	44% 1 8% 23% 19% 4	5818
April	1st to 10th	Day	38% 3 10% 23% 19% 7%	2400
	11th to 20th	Day	39% 2 5% 23% 23% 7%	2374
	21st to end	Day	36% 3 10% 26% 22% 3	2400
May	1st to 10th	Day	47% 3 13% 24% 11% 2	5797
	11th to 20th	Day	51% 4 14% 22% 9% 1	5865
	21st to end	Day	43% 3 11% 25% 16% 2	6447
June	1st to 10th	Day	43% 5% 14% 19% 17% 1	2600
	11th to 20th	Day	34% 6% 15% 27% 16% 2	2600
	21st to end	Day	36% 6% 17% 25% 13% 4	2600
July	1st to 10th	Day	38% 8% 19% 24% 10% 1	5835
	11th to 20th	Day	37% 10% 29% 20% 4 1	5831
	21st to end	Day	48% 8% 23% 17% 4	6072
August	1st to 10th	Day	25% 5% 13% 38% 18% 1	3893
	11th to 20th	Day	33% 5% 17% 28% 16% 3	3885
	21st to end	Day	31% 5% 14% 21% 25% 4	4311
September	1st to 10th	Day	39% 4 13% 21% 17% 6%	2369
	11th to 20th	Day	40% 4 11% 20% 20% 4	2200
	21st to end	Day	34% 4 10% 23% 23% 7%	2200
October	1st to 10th	Day	23% 2 4 16% 33% 22%	3590
	11th to 20th	Day	20% 2 4 18% 31% 26%	3544
	21st to end	Day	26% 2 4 23% 34% 11%	3297
November	1st to 10th	Day	35% 2 7% 20% 27% 10%	1852
	11th to 20th	Day	35% 2 5% 22% 27% 9%	1890
	21st to end	Day	39% 3 6% 19% 25% 7%	1890
December	1st to 10th	Day	45% 2 5% 18% 26% 4	3020
	11th to 20th	Day	49% 1 7% 20% 17% 6%	3460
	21st to end	Day	48% 2 5% 26% 18% 1	4565
January	1st to 10th	Night	46% 1 4 24% 22% 3	6019
	11th to 20th	Night	44% 2 3 21% 24% 6%	5818
	21st to end	Night	46% 2 4 18% 24% 6%	6116
February	1st to 10th	Night	45% 2 5% 21% 21% 7%	2401
	11th to 20th	Night	49% 2 5% 18% 19% 8%	2339
	21st to end	Night	46% 3 6% 16% 21% 9%	1980
March	1st to 10th	Night	53% 2 4 15% 18% 7%	5373
	11th to 20th	Night	36% 2 7% 18% 22% 16%	5217
	21st to end	Night	45% 2 5% 24% 18% 6%	5155
April	1st to 10th	Night	36% 3 11% 24% 20% 7%	2000
	11th to 20th	Night	36% 3 6% 22% 22% 12%	1975
	21st to end	Night	34% 3 9% 27% 22% 5%	2000
May	1st to 10th	Night	46% 3 13% 21% 15% 2	4160
	11th to 20th	Night	54% 4 13% 20% 8% 1	4033
	21st to end	Night	40% 4 12% 26% 16% 2	4429
June	1st to 10th	Night	35% 5% 16% 22% 20% 2	1800
	11th to 20th	Night	26% 5% 18% 30% 18% 3	1800
	21st to end	Night	33% 6% 15% 23% 18% 4	1800
July	1st to 10th	Night	39% 6% 22% 22% 9% 2	4015
	11th to 20th	Night	36% 9% 31% 19% 5% 1	4006
	21st to end	Night	47% 9% 24% 16% 4	4447
August	1st to 10th	Night	21% 5% 14% 40% 19% 1	3232
	11th to 20th	Night	26% 5% 20% 30% 16% 3	3230
	21st to end	Night	27% 4 16% 22% 26% 6%	3586
September	1st to 10th	Night	36% 5% 15% 20% 17% 7%	2010
	11th to 20th	Night	38% 4 11% 21% 21% 5%	2200
	21st to end	Night	31% 3 9% 24% 25% 8%	2200
October	1st to 10th	Night	21% 3 4 18% 32% 22%	3590
	11th to 20th	Night	20% 2 3 17% 31% 27%	3592
	21st to end	Night	24% 2 3 24% 32% 15%	4479
November	1st to 10th	Night	32% 2 6% 20% 26% 13%	2666
	11th to 20th	Night	33% 2 6% 20% 29% 11%	2730
	21st to end	Night	39% 2 5% 22% 24% 8%	2730
December	1st to 10th	Night	42% 2 5% 21% 27% 4	4380
	11th to 20th	Night	46% 2 5% 19% 23% 4	4954
	21st to end	Night	47% 2 5% 27% 17% 2	6633

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	29% 22% 31% 14% 4	330
	11th to 20th	Day	28% 22% 30% 14% 6%	330
	21st to end	Day	26% 23% 35% 13% 3	363
February	1st to 10th	Day	27% 20% 32% 14% 6% 1	300
	11th to 20th	Day	37% 20% 29% 12% 2 1	300
	21st to end	Day	31% 21% 35% 10% 2	249
March	1st to 10th	Day	27% 22% 32% 14% 4 2	300
	11th to 20th	Day	27% 16% 35% 16% 6% 1	391
	21st to end	Day	24% 17% 32% 20% 7%	550
April	1st to 10th	Day	23% 15% 27% 22% 11% 2	500
	11th to 20th	Day	19% 15% 30% 21% 13% 2	492
	21st to end	Day	14% 13% 30% 26% 16% 1	500
May	1st to 10th	Day	16% 9% 29% 25% 16% 5%	503
	11th to 20th	Day	10% 9% 28% 26% 17% 9%	527
	21st to end	Day	13% 6% 21% 29% 18% 13%	573
June	1st to 10th	Day	14% 5% 16% 28% 24% 13%	530
	11th to 20th	Day	9% 3 16% 27% 26% 20%	530
	21st to end	Day	12% 2 13% 23% 29% 20%	530
July	1st to 10th	Day	8% 2 8% 28% 29% 24%	525
	11th to 20th	Day	8% 3 7% 22% 31% 30%	524
	21st to end	Day	9% 3 10% 20% 35% 24%	576
August	1st to 10th	Day	9% 3 11% 26% 28% 24%	526
	11th to 20th	Day	9% 2 11% 28% 33% 17%	519
	21st to end	Day	13% 4 10% 22% 33% 19%	583
September	1st to 10th	Day	11% 3 11% 33% 32% 11%	530
	11th to 20th	Day	12% 5% 11% 23% 36% 14%	530
	21st to end	Day	13% 3 16% 28% 28% 11%	530
October	1st to 10th	Day	11% 7% 21% 32% 21% 8%	530
	11th to 20th	Day	11% 8% 26% 34% 19% 2	518
	21st to end	Day	20% 11% 25% 29% 13% 2	363
November	1st to 10th	Day	22% 8% 30% 25% 12% 4	330
	11th to 20th	Day	15% 15% 39% 23% 6% 1	330
	21st to end	Day	17% 20% 33% 18% 9% 2	330
December	1st to 10th	Day	32% 16% 31% 16% 5% 1	330
	11th to 20th	Day	23% 20% 31% 18% 7% 2	330
	21st to end	Day	29% 17% 31% 17% 5% 2	363
January	1st to 10th	Night	24% 13% 35% 24% 4	840
	11th to 20th	Night	25% 16% 28% 25% 6%	840
	21st to end	Night	22% 15% 35% 26% 3	924
February	1st to 10th	Night	24% 12% 31% 29% 4	801
	11th to 20th	Night	27% 14% 30% 26% 3	783
	21st to end	Night	26% 16% 30% 26% 2	660
March	1st to 10th	Night	20% 16% 30% 29% 5%	800
	11th to 20th	Night	18% 14% 33% 27% 9% 1	800
	21st to end	Night	18% 11% 32% 28% 10%	749
April	1st to 10th	Night	14% 13% 32% 28% 13%	600
	11th to 20th	Night	17% 7% 32% 29% 13% 1	593
	21st to end	Night	15% 8% 25% 35% 16% 2	600
May	1st to 10th	Night	13% 5% 25% 33% 23% 2	600
	11th to 20th	Night	11% 6% 22% 31% 27% 4	591
	21st to end	Night	9% 2 11% 38% 34% 6%	650
June	1st to 10th	Night	8% 2 10% 38% 35% 7%	600
	11th to 20th	Night	6% 1 10% 29% 40% 14%	600
	21st to end	Night	7% 2 8% 26% 46% 11%	600
July	1st to 10th	Night	7% 2 4 28% 45% 14%	585
	11th to 20th	Night	7% 1 6% 23% 44% 20%	582
	21st to end	Night	8% 1 7% 24% 44% 16%	657
August	1st to 10th	Night	4 1 4 25% 51% 15%	597
	11th to 20th	Night	9% 1 5% 30% 44% 11%	594
	21st to end	Night	13% 1 6% 29% 41% 10%	660
September	1st to 10th	Night	9% 2 10% 31% 40% 8%	610
	11th to 20th	Night	13% 3 10% 29% 38% 6%	800
	21st to end	Night	10% 3 14% 34% 35% 4	800
October	1st to 10th	Night	11% 4 20% 33% 28% 5%	800
	11th to 20th	Night	12% 6% 22% 37% 21% 2	800
	21st to end	Night	18% 7% 18% 36% 18% 2	880
November	1st to 10th	Night	15% 6% 21% 35% 20% 3	820
	11th to 20th	Night	14% 9% 29% 34% 13% 1	840
	21st to end	Night	19% 9% 29% 30% 12% 1	840
December	1st to 10th	Night	23% 13% 25% 30% 8%	840
	11th to 20th	Night	23% 12% 26% 28% 10%	840
	21st to end	Night	27% 11% 27% 28% 7%	924

Page generated at 2026-01-29 00:21:46. Version ac07

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