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 2024-11-28.

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% 42%	101042
	Night	13% 6% 2 6% 4 4 4 4 5% 7% 45%	98475
Transparency	Day	40% 3 10% 22% 19% 5%	104838
	Night	38% 3 9% 22% 21% 7%	102804
Seeing	Day	17% 10% 22% 23% 19% 10%	14557
	Night	16% 8% 21% 30% 21% 4	24549

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% 12% 3 5% 4 4 3 4 5% 6% 37%	2836
	11th to 20th	Day	18% 8% 3 7% 4 3 2 2 3 4 47%	2972
	21st to end	Day	24% 10% 2 4 2 3 3 2 3 6% 41%	3476
February	1st to 10th	Day	21% 9% 2 6% 4 3 3 3 4 5% 40%	1900
	11th to 20th	Day	23% 7% 3 5% 3 3 3 3 4 5% 40%	1848
	21st to end	Day	22% 9% 3 5% 3 4 3 3 4 5% 38%	1570
March	1st to 10th	Day	24% 8% 3 6% 4 4 4 4 4 6% 33%	3120
	11th to 20th	Day	15% 7% 3 6% 4 4 4 3 5% 7% 42%	3311
	21st to end	Day	15% 6% 3 7% 5% 4 4 4 5% 7% 38%	4056
April	1st to 10th	Day	12% 6% 2 6% 4 4 4 4 5% 6% 47%	2280
	11th to 20th	Day	14% 6% 2 6% 4 4 4 4 4 7% 45%	2254
	21st to end	Day	9% 5% 2 5% 5% 4 4 4 6% 8% 48%	2280
May	1st to 10th	Day	11% 5% 2 6% 5% 4 5% 5% 6% 9% 42%	4009
	11th to 20th	Day	16% 6% 2 6% 5% 4 5% 4 6% 8% 37%	4081
	21st to end	Day	9% 5% 2 6% 5% 5% 5% 4 7% 9% 42%	4476
June	1st to 10th	Day	10% 6% 2 6% 5% 6% 7% 5% 7% 9% 35%	2470
	11th to 20th	Day	6% 4 2 5% 5% 5% 6% 6% 7% 10% 44%	2470
	21st to end	Day	7% 6% 2 5% 5% 5% 6% 5% 7% 9% 43%	2470
July	1st to 10th	Day	6% 5% 2 8% 7% 7% 7% 6% 9% 13% 30%	4120
	11th to 20th	Day	8% 6% 2 7% 6% 6% 7% 6% 9% 13% 31%	4120
	21st to end	Day	13% 9% 3 9% 6% 7% 8% 6% 8% 9% 22%	4351
August	1st to 10th	Day	3 3 1 4 4 5% 5% 4 8% 9% 54%	3785
	11th to 20th	Day	6% 4 2 6% 5% 5% 5% 4 7% 9% 46%	3729
	21st to end	Day	7% 4 2 5% 4 5% 4 4 5% 7% 51%	4180
September	1st to 10th	Day	11% 5% 3 7% 4 5% 6% 5% 6% 9% 41%	2251
	11th to 20th	Day	13% 7% 2 6% 4 5% 6% 3 6% 7% 41%	2090
	21st to end	Day	11% 5% 2 5% 4 4 4 3 5% 6% 51%	2090
October	1st to 10th	Day	10% 5% 1 5% 3 3 3 3 5% 7% 54%	2090
	11th to 20th	Day	9% 4 2 5% 3 4 4 3 5% 6% 56%	2079
	21st to end	Day	13% 4 2 5% 3 4 3 3 4 5% 54%	1956
November	1st to 10th	Day	14% 5% 2 5% 4 4 3 3 4 5% 53%	1762
	11th to 20th	Day	13% 5% 2 5% 3 3 4 3 4 6% 52%	1800
	21st to end	Day	16% 6% 2 5% 3 3 3 4 5% 7% 46%	1773
December	1st to 10th	Day	23% 9% 2 5% 3 4 4 4 4 5% 38%	1710
	11th to 20th	Day	19% 7% 2 7% 4 4 4 2 3 4 43%	2153
	21st to end	Day	19% 10% 3 7% 4 4 4 3 5% 6% 35%	3124
January	1st to 10th	Night	19% 11% 2 6% 3 3 4 3 4 5% 40%	4109
	11th to 20th	Night	19% 9% 4 5% 4 3 3 2 4 5% 43%	3983
	21st to end	Night	22% 13% 2 4 3 3 3 2 3 4 39%	4180
February	1st to 10th	Night	19% 8% 3 6% 3 3 3 3 4 5% 43%	2280
	11th to 20th	Night	22% 7% 3 6% 4 3 3 2 4 4 43%	2218
	21st to end	Night	22% 6% 3 6% 4 4 4 4 5% 6% 38%	1884
March	1st to 10th	Night	25% 9% 3 6% 4 3 3 2 4 5% 35%	3733
	11th to 20th	Night	12% 6% 2 5% 3 3 4 4 5% 7% 48%	3647
	21st to end	Night	17% 8% 3 8% 5% 3 4 3 4 5% 41%	3603
April	1st to 10th	Night	12% 6% 2 5% 3 4 4 4 6% 7% 47%	1900
	11th to 20th	Night	14% 5% 2 5% 3 4 4 3 4 7% 49%	1875
	21st to end	Night	11% 5% 1 5% 4 3 3 3 6% 7% 51%	1900
May	1st to 10th	Night	9% 6% 2 7% 5% 4 5% 4 5% 8% 44%	2884
	11th to 20th	Night	15% 7% 2 7% 5% 5% 5% 3 6% 6% 39%	2812
	21st to end	Night	6% 4 2 5% 4 5% 6% 4 7% 12% 45%	3079
June	1st to 10th	Night	7% 5% 3 5% 6% 6% 4 6% 7% 9% 42%	1710
	11th to 20th	Night	5% 2 1 4 3 4 5% 5% 6% 11% 53%	1710
	21st to end	Night	6% 4 2 6% 5% 5% 5% 4 8% 10% 45%	1710
July	1st to 10th	Night	9% 5% 2 8% 6% 6% 6% 6% 6% 11% 36%	2840
	11th to 20th	Night	10% 5% 3 5% 5% 5% 5% 5% 8% 12% 36%	2840
	21st to end	Night	11% 9% 3 9% 7% 7% 7% 5% 7% 9% 25%	3198
August	1st to 10th	Night	2 2 1 4 3 4 5% 4 6% 10% 59%	3144
	11th to 20th	Night	5% 3 1 4 4 4 4 5% 6% 10% 55%	3100
	21st to end	Night	6% 4 2 4 4 3 5% 4 6% 7% 56%	3476
September	1st to 10th	Night	8% 5% 3 5% 5% 4 5% 4 6% 8% 48%	1909
	11th to 20th	Night	12% 6% 2 6% 4 4 4 3 6% 8% 44%	2090
	21st to end	Night	7% 5% 2 6% 4 4 3 3 6% 6% 55%	2090
October	1st to 10th	Night	9% 5% 1 4 3 3 3 3 3 6% 61%	2090
	11th to 20th	Night	11% 5% 2 5% 4 3 3 3 4 5% 56%	2098
	21st to end	Night	15% 5% 2 4 3 3 3 2 3 5% 56%	2641
November	1st to 10th	Night	11% 4 2 5% 4 4 3 3 4 5% 54%	2536
	11th to 20th	Night	13% 6% 2 4 3 2 3 3 4 5% 54%	2600
	21st to end	Night	15% 6% 2 5% 3 3 4 3 4 6% 48%	2562
December	1st to 10th	Night	21% 6% 2 5% 5% 3 4 4 5% 6% 40%	2470
	11th to 20th	Night	18% 6% 2 5% 3 3 3 3 3 5% 48%	3042
	21st to end	Night	19% 8% 3 7% 4 4 4 4 7% 7% 32%	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	50% 1 4 19% 21% 4	2837
	11th to 20th	Day	45% 1 5% 24% 22% 2	2972
	21st to end	Day	48% 1 6% 19% 21% 4	3476
February	1st to 10th	Day	48% 2 6% 20% 19% 5%	1900
	11th to 20th	Day	49% 2 4 19% 19% 6%	1858
	21st to end	Day	50% 2 5% 14% 23% 6%	1570
March	1st to 10th	Day	54% 1 8% 11% 15% 10%	3120
	11th to 20th	Day	43% 2 7% 21% 21% 6%	3311
	21st to end	Day	46% 1 10% 20% 19% 4	4056
April	1st to 10th	Day	38% 3 10% 23% 19% 7%	2280
	11th to 20th	Day	40% 3 6% 22% 23% 7%	2254
	21st to end	Day	35% 3 9% 27% 23% 3	2280
May	1st to 10th	Day	40% 3 12% 28% 16% 2	4046
	11th to 20th	Day	45% 3 11% 28% 12% 1	4085
	21st to end	Day	39% 3 12% 29% 16% 1	4489
June	1st to 10th	Day	43% 5% 14% 20% 17% 1	2470
	11th to 20th	Day	33% 6% 15% 28% 17% 3	2470
	21st to end	Day	36% 6% 16% 25% 13% 4	2470
July	1st to 10th	Day	42% 7% 22% 21% 6% 1	4055
	11th to 20th	Day	40% 8% 23% 22% 5% 1	4051
	21st to end	Day	56% 7% 14% 17% 6%	4212
August	1st to 10th	Day	24% 5% 13% 38% 19% 1	3773
	11th to 20th	Day	33% 4 16% 28% 16% 3	3765
	21st to end	Day	31% 5% 14% 21% 24% 4	4179
September	1st to 10th	Day	39% 4 14% 20% 17% 6%	2251
	11th to 20th	Day	42% 4 11% 19% 20% 5%	2090
	21st to end	Day	34% 3 10% 23% 22% 8%	2090
October	1st to 10th	Day	22% 2 4 16% 33% 23%	3480
	11th to 20th	Day	20% 2 4 18% 30% 26%	3435
	21st to end	Day	25% 2 4 23% 34% 12%	3194
November	1st to 10th	Day	35% 2 6% 20% 27% 10%	1762
	11th to 20th	Day	35% 2 4 21% 27% 10%	1800
	21st to end	Day	39% 3 6% 19% 25% 8%	1773
December	1st to 10th	Day	49% 2 7% 16% 20% 5%	1710
	11th to 20th	Day	47% 1 5% 20% 22% 5%	2150
	21st to end	Day	52% 2 6% 21% 17% 2	3124
January	1st to 10th	Night	49% 1 4 18% 25% 3	4109
	11th to 20th	Night	47% 1 4 23% 19% 6%	3983
	21st to end	Night	51% 2 3 19% 20% 5%	4180
February	1st to 10th	Night	45% 2 5% 21% 21% 6%	2280
	11th to 20th	Night	47% 2 5% 18% 20% 8%	2219
	21st to end	Night	48% 3 6% 15% 20% 9%	1884
March	1st to 10th	Night	53% 2 6% 16% 16% 8%	3733
	11th to 20th	Night	36% 2 9% 21% 22% 10%	3647
	21st to end	Night	47% 2 5% 22% 20% 3	3603
April	1st to 10th	Night	36% 3 11% 24% 20% 6%	1900
	11th to 20th	Night	36% 3 6% 21% 22% 12%	1875
	21st to end	Night	33% 3 9% 27% 23% 5%	1900
May	1st to 10th	Night	40% 3 11% 23% 20% 3	2912
	11th to 20th	Night	46% 4 13% 25% 11% 2	2813
	21st to end	Night	32% 4 13% 30% 18% 2	3087
June	1st to 10th	Night	36% 5% 16% 22% 19% 2	1710
	11th to 20th	Night	25% 5% 18% 31% 18% 3	1710
	21st to end	Night	33% 6% 15% 22% 19% 5%	1710
July	1st to 10th	Night	42% 6% 24% 20% 6% 2	2795
	11th to 20th	Night	37% 7% 26% 22% 7% 1	2786
	21st to end	Night	54% 7% 16% 16% 6% 1	3096
August	1st to 10th	Night	20% 5% 14% 41% 20% 1	3132
	11th to 20th	Night	25% 5% 19% 31% 17% 3	3130
	21st to end	Night	27% 4 15% 22% 26% 6%	3476
September	1st to 10th	Night	35% 5% 16% 20% 17% 7%	1909
	11th to 20th	Night	39% 4 11% 20% 21% 5%	2090
	21st to end	Night	30% 3 9% 24% 25% 9%	2090
October	1st to 10th	Night	20% 3 4 18% 32% 22%	3480
	11th to 20th	Night	20% 2 3 17% 31% 27%	3481
	21st to end	Night	23% 2 3 24% 32% 16%	4340
November	1st to 10th	Night	33% 2 6% 20% 26% 13%	2536
	11th to 20th	Night	34% 2 5% 19% 29% 12%	2600
	21st to end	Night	38% 2 5% 22% 24% 8%	2562
December	1st to 10th	Night	45% 2 8% 19% 22% 4	2470
	11th to 20th	Night	42% 1 6% 20% 26% 5%	3044
	21st to end	Night	49% 3 5% 21% 19% 2	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	27% 23% 31% 15% 4	270
	11th to 20th	Day	30% 21% 29% 13% 7%	270
	21st to end	Day	26% 22% 36% 13% 3	297
February	1st to 10th	Day	29% 21% 32% 13% 6%	270
	11th to 20th	Day	35% 20% 30% 13% 2 1	270
	21st to end	Day	33% 23% 34% 9% 1	225
March	1st to 10th	Day	26% 20% 33% 15% 4 2	270
	11th to 20th	Day	26% 15% 34% 17% 6% 1	356
	21st to end	Day	23% 17% 31% 20% 8%	506
April	1st to 10th	Day	24% 14% 27% 23% 11% 2	460
	11th to 20th	Day	19% 15% 29% 22% 13% 2	452
	21st to end	Day	15% 13% 30% 25% 16% 1	460
May	1st to 10th	Day	15% 9% 28% 25% 17% 5%	463
	11th to 20th	Day	9% 8% 27% 28% 18% 10%	487
	21st to end	Day	11% 5% 20% 30% 19% 14%	529
June	1st to 10th	Day	15% 5% 15% 27% 25% 13%	490
	11th to 20th	Day	8% 3 16% 26% 26% 21%	490
	21st to end	Day	12% 2 14% 25% 29% 18%	490
July	1st to 10th	Day	9% 2 8% 26% 29% 25%	485
	11th to 20th	Day	8% 3 7% 22% 30% 29%	484
	21st to end	Day	10% 3 10% 20% 34% 24%	532
August	1st to 10th	Day	8% 3 11% 26% 28% 24%	486
	11th to 20th	Day	9% 2 12% 28% 33% 15%	479
	21st to end	Day	14% 3 8% 21% 34% 19%	539
September	1st to 10th	Day	11% 3 10% 30% 33% 12%	490
	11th to 20th	Day	13% 5% 11% 22% 35% 13%	490
	21st to end	Day	14% 3 16% 28% 29% 12%	490
October	1st to 10th	Day	11% 6% 20% 32% 22% 9%	490
	11th to 20th	Day	12% 8% 27% 33% 18% 2	479
	21st to end	Day	18% 11% 24% 31% 14% 2	330
November	1st to 10th	Day	22% 8% 30% 25% 11% 4	300
	11th to 20th	Day	17% 16% 37% 22% 7% 1	300
	21st to end	Day	18% 18% 31% 20% 11% 2	291
December	1st to 10th	Day	33% 14% 29% 17% 6% 1	270
	11th to 20th	Day	25% 20% 29% 17% 7% 2	270
	21st to end	Day	30% 17% 31% 16% 4 1	297
January	1st to 10th	Night	24% 13% 35% 23% 5%	760
	11th to 20th	Night	26% 15% 27% 25% 7%	760
	21st to end	Night	22% 15% 34% 26% 3	836
February	1st to 10th	Night	24% 12% 31% 29% 4	760
	11th to 20th	Night	27% 13% 30% 27% 3	743
	21st to end	Night	27% 16% 30% 25% 2	628
March	1st to 10th	Night	20% 15% 30% 30% 5%	760
	11th to 20th	Night	17% 13% 33% 27% 9% 1	760
	21st to end	Night	18% 12% 32% 28% 10%	712
April	1st to 10th	Night	13% 13% 32% 28% 14%	570
	11th to 20th	Night	18% 7% 32% 28% 13% 1	563
	21st to end	Night	15% 8% 26% 34% 16% 2	570
May	1st to 10th	Night	12% 5% 25% 32% 24% 2	570
	11th to 20th	Night	11% 4 21% 31% 28% 4	561
	21st to end	Night	8% 2 11% 38% 36% 6%	617
June	1st to 10th	Night	8% 2 10% 37% 35% 8%	570
	11th to 20th	Night	5% 1 10% 29% 41% 14%	570
	21st to end	Night	7% 2 9% 27% 45% 11%	570
July	1st to 10th	Night	8% 2 4 28% 45% 14%	555
	11th to 20th	Night	7% 1 6% 24% 44% 19%	552
	21st to end	Night	8% 1 7% 24% 44% 15%	624
August	1st to 10th	Night	4 1 4 25% 51% 16%	567
	11th to 20th	Night	9% 1 6% 30% 44% 10%	564
	21st to end	Night	13% 1 5% 28% 42% 11%	627
September	1st to 10th	Night	9% 2 10% 30% 41% 8%	579
	11th to 20th	Night	14% 4 10% 29% 38% 6%	760
	21st to end	Night	9% 3 14% 34% 36% 4	760
October	1st to 10th	Night	11% 3 20% 32% 29% 6%	760
	11th to 20th	Night	12% 6% 23% 35% 21% 2	760
	21st to end	Night	18% 6% 18% 36% 19% 3	836
November	1st to 10th	Night	14% 6% 21% 35% 21% 3	780
	11th to 20th	Night	15% 9% 29% 33% 13% 1	800
	21st to end	Night	19% 8% 29% 30% 13% 1	789
December	1st to 10th	Night	23% 13% 25% 31% 9%	760
	11th to 20th	Night	24% 11% 28% 28% 10%	760
	21st to end	Night	27% 10% 28% 28% 7%	836

Page generated at 2024-11-24 23:22:21. Version ac07

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