Tuscaloosa
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Tuscaloosa clear sky chart from 2005-11-06 to 2024-11-05.

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 4 4 4 6% 8% 44%	100944
	Night	13% 6% 2 6% 4 4 4 4 5% 7% 45%	98005
Transparency	Day	36% 7% 11% 20% 19% 6%	104757
	Night	35% 6% 10% 19% 20% 8%	102317
Seeing	Day	14% 8% 21% 24% 21% 11%	14567
	Night	14% 7% 22% 30% 22% 5%	24382

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% 11% 3 6% 4 3 4 4 5% 6% 39%	2836
	11th to 20th	Day	15% 7% 3 6% 3 4 4 2 4 4 49%	3104
	21st to end	Day	23% 10% 2 4 3 2 2 2 3 5% 43%	3476
February	1st to 10th	Day	19% 9% 3 6% 4 3 3 3 4 5% 40%	1900
	11th to 20th	Day	22% 7% 2 5% 4 4 4 2 3 5% 41%	1848
	21st to end	Day	22% 7% 3 6% 4 3 3 3 4 5% 39%	1570
March	1st to 10th	Day	23% 8% 4 6% 4 4 4 3 5% 6% 34%	3120
	11th to 20th	Day	14% 6% 2 6% 4 3 4 4 6% 7% 42%	3256
	21st to end	Day	16% 8% 2 7% 5% 4 5% 3 5% 6% 39%	4150
April	1st to 10th	Day	12% 5% 2 5% 4 5% 4 4 5% 8% 47%	2280
	11th to 20th	Day	12% 6% 2 6% 4 4 4 3 5% 7% 47%	2254
	21st to end	Day	9% 4 2 5% 5% 4 5% 4 6% 8% 49%	2280
May	1st to 10th	Day	9% 4 2 6% 5% 4 5% 4 6% 9% 46%	3889
	11th to 20th	Day	15% 6% 2 6% 4 4 4 4 7% 9% 40%	4081
	21st to end	Day	9% 5% 2 6% 5% 5% 5% 5% 7% 9% 44%	4476
June	1st to 10th	Day	9% 6% 3 7% 6% 5% 6% 5% 8% 10% 36%	2470
	11th to 20th	Day	6% 4 1 5% 5% 5% 5% 5% 8% 10% 47%	2470
	21st to end	Day	6% 5% 2 6% 5% 4 5% 6% 7% 10% 43%	2547
July	1st to 10th	Day	7% 5% 2 8% 6% 7% 7% 6% 9% 12% 31%	4226
	11th to 20th	Day	8% 5% 2 6% 5% 6% 6% 7% 8% 11% 36%	4120
	21st to end	Day	10% 7% 3 9% 7% 7% 7% 5% 7% 11% 25%	4183
August	1st to 10th	Day	4 2 1 4 3 4 4 3 7% 10% 58%	3785
	11th to 20th	Day	6% 4 2 6% 4 5% 4 4 6% 9% 50%	3729
	21st to end	Day	7% 3 2 4 4 5% 6% 4 7% 9% 50%	4180
September	1st to 10th	Day	9% 5% 2 7% 5% 5% 4 4 7% 9% 44%	2275
	11th to 20th	Day	13% 6% 2 6% 4 5% 4 4 7% 7% 42%	2090
	21st to end	Day	9% 5% 2 6% 3 4 4 3 6% 7% 51%	2090
October	1st to 10th	Day	8% 4 2 6% 4 3 4 4 4 6% 56%	2090
	11th to 20th	Day	9% 4 2 5% 3 3 3 3 4 6% 59%	2043
	21st to end	Day	13% 4 1 4 3 3 3 2 4 5% 55%	2011
November	1st to 10th	Day	10% 6% 2 5% 3 3 3 3 3 6% 56%	1708
	11th to 20th	Day	14% 4 2 4 4 3 3 3 4 6% 53%	1710
	21st to end	Day	15% 6% 2 6% 3 3 4 3 5% 6% 48%	1710
December	1st to 10th	Day	19% 9% 2 5% 4 3 4 3 5% 6% 40%	1710
	11th to 20th	Day	17% 9% 3 5% 4 4 5% 3 3 5% 43%	2153
	21st to end	Day	17% 9% 3 8% 4 4 4 3 4 6% 38%	3124
January	1st to 10th	Night	19% 11% 2 6% 4 4 3 2 4 5% 41%	4109
	11th to 20th	Night	16% 8% 3 6% 3 3 4 3 3 4 47%	3853
	21st to end	Night	22% 11% 2 6% 4 3 3 2 3 3 41%	4180
February	1st to 10th	Night	17% 8% 2 6% 4 3 3 3 5% 6% 42%	2280
	11th to 20th	Night	21% 6% 3 6% 3 4 3 3 4 4 44%	2218
	21st to end	Night	20% 6% 2 7% 4 4 4 3 5% 7% 39%	1884
March	1st to 10th	Night	24% 10% 3 6% 3 3 4 3 4 6% 35%	3733
	11th to 20th	Night	13% 5% 2 5% 4 3 4 4 6% 7% 47%	3690
	21st to end	Night	16% 9% 3 7% 5% 3 4 3 5% 5% 40%	3509
April	1st to 10th	Night	13% 6% 2 5% 4 4 3 4 6% 7% 47%	1900
	11th to 20th	Night	14% 5% 1 5% 3 4 3 3 4 7% 50%	1875
	21st to end	Night	9% 4 1 5% 5% 4 5% 3 6% 7% 52%	1900
May	1st to 10th	Night	9% 6% 2 7% 5% 5% 4 4 5% 8% 44%	3002
	11th to 20th	Night	16% 7% 2 6% 4 4 4 4 5% 8% 41%	2812
	21st to end	Night	6% 3 1 5% 5% 5% 5% 6% 8% 10% 46%	3079
June	1st to 10th	Night	7% 6% 2 6% 6% 7% 5% 5% 7% 10% 40%	1710
	11th to 20th	Night	5% 4 1 4 5% 4 5% 5% 7% 11% 50%	1710
	21st to end	Night	4 5% 2 5% 4 5% 6% 5% 8% 11% 43%	1607
July	1st to 10th	Night	6% 6% 2 8% 6% 7% 6% 5% 8% 12% 34%	2702
	11th to 20th	Night	7% 5% 2 5% 5% 4 7% 5% 9% 12% 37%	2840
	21st to end	Night	9% 8% 4 10% 7% 6% 6% 6% 8% 10% 27%	3365
August	1st to 10th	Night	2 2 1 4 4 5% 5% 4 8% 9% 56%	3144
	11th to 20th	Night	5% 3 2 5% 4 4 5% 4 7% 9% 54%	3100
	21st to end	Night	6% 4 2 6% 4 4 4 5% 6% 10% 50%	3476
September	1st to 10th	Night	9% 6% 2 7% 5% 5% 5% 4 6% 6% 46%	1900
	11th to 20th	Night	12% 6% 2 5% 4 4 4 4 5% 9% 46%	2076
	21st to end	Night	7% 5% 2 6% 4 3 4 4 5% 6% 54%	2090
October	1st to 10th	Night	7% 4 2 5% 3 2 4 3 5% 5% 60%	2090
	11th to 20th	Night	10% 5% 2 4 2 3 3 2 5% 7% 57%	2133
	21st to end	Night	14% 6% 2 4 3 3 3 2 3 4 57%	2584
November	1st to 10th	Night	10% 5% 1 4 3 3 4 3 4 6% 57%	2470
	11th to 20th	Night	12% 5% 2 4 3 3 3 3 5% 6% 54%	2470
	21st to end	Night	13% 5% 3 5% 4 4 3 3 5% 6% 49%	2470
December	1st to 10th	Night	18% 6% 2 5% 4 4 4 2 4 6% 43%	2470
	11th to 20th	Night	17% 6% 2 6% 3 3 3 3 3 5% 48%	3042
	21st to end	Night	18% 7% 3 6% 4 3 4 4 6% 8% 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	45% 5% 7% 17% 22% 4	2837
	11th to 20th	Day	39% 5% 6% 24% 22% 4	3104
	21st to end	Day	46% 3 7% 17% 19% 8%	3476
February	1st to 10th	Day	47% 4 7% 19% 18% 6%	1900
	11th to 20th	Day	48% 3 5% 16% 20% 8%	1858
	21st to end	Day	48% 5% 7% 14% 20% 8%	1570
March	1st to 10th	Day	50% 5% 9% 11% 17% 7%	3120
	11th to 20th	Day	40% 6% 8% 19% 19% 8%	3256
	21st to end	Day	43% 7% 9% 15% 20% 6%	4150
April	1st to 10th	Day	36% 7% 10% 20% 20% 8%	2280
	11th to 20th	Day	38% 5% 8% 20% 21% 9%	2254
	21st to end	Day	31% 7% 10% 23% 26% 3	2280
May	1st to 10th	Day	32% 9% 13% 27% 16% 3	3924
	11th to 20th	Day	39% 8% 13% 27% 12% 2	4085
	21st to end	Day	33% 10% 14% 27% 15% 1	4489
June	1st to 10th	Day	39% 11% 15% 20% 14% 2	2470
	11th to 20th	Day	28% 10% 18% 26% 17% 2	2470
	21st to end	Day	34% 11% 16% 22% 13% 4	2547
July	1st to 10th	Day	40% 13% 21% 20% 5% 1	4161
	11th to 20th	Day	37% 12% 22% 22% 6% 1	4051
	21st to end	Day	51% 12% 14% 18% 5%	4049
August	1st to 10th	Day	20% 9% 13% 34% 24% 1	3773
	11th to 20th	Day	30% 8% 16% 28% 15% 3	3765
	21st to end	Day	29% 10% 16% 21% 19% 5%	4179
September	1st to 10th	Day	37% 9% 14% 16% 20% 5%	2275
	11th to 20th	Day	39% 8% 11% 16% 21% 5%	2090
	21st to end	Day	33% 6% 11% 22% 21% 8%	2090
October	1st to 10th	Day	22% 4 6% 12% 30% 26%	3480
	11th to 20th	Day	18% 3 4 16% 30% 30%	3374
	21st to end	Day	22% 3 5% 18% 37% 14%	3288
November	1st to 10th	Day	33% 3 6% 19% 28% 11%	1708
	11th to 20th	Day	34% 3 6% 18% 28% 11%	1710
	21st to end	Day	38% 4 7% 17% 25% 8%	1710
December	1st to 10th	Day	44% 6% 8% 16% 19% 6%	1710
	11th to 20th	Day	45% 4 7% 17% 23% 5%	2150
	21st to end	Day	45% 6% 8% 19% 20% 2	3124
January	1st to 10th	Night	46% 4 5% 15% 26% 4	4109
	11th to 20th	Night	41% 4 5% 22% 19% 8%	3853
	21st to end	Night	49% 4 3 17% 22% 5%	4180
February	1st to 10th	Night	43% 4 6% 18% 21% 8%	2280
	11th to 20th	Night	45% 4 5% 16% 20% 10%	2219
	21st to end	Night	44% 6% 7% 15% 18% 10%	1884
March	1st to 10th	Night	50% 5% 8% 14% 16% 8%	3733
	11th to 20th	Night	35% 6% 9% 19% 21% 11%	3690
	21st to end	Night	44% 5% 8% 19% 19% 5%	3509
April	1st to 10th	Night	36% 6% 11% 19% 20% 8%	1900
	11th to 20th	Night	34% 5% 7% 20% 23% 11%	1875
	21st to end	Night	29% 8% 10% 23% 24% 6%	1900
May	1st to 10th	Night	34% 11% 12% 20% 19% 4	3032
	11th to 20th	Night	39% 8% 13% 24% 13% 2	2813
	21st to end	Night	27% 11% 15% 26% 18% 3	3087
June	1st to 10th	Night	37% 11% 13% 19% 17% 2	1710
	11th to 20th	Night	26% 8% 21% 26% 17% 4	1710
	21st to end	Night	30% 10% 18% 20% 18% 4	1607
July	1st to 10th	Night	39% 11% 24% 17% 7% 1	2657
	11th to 20th	Night	34% 12% 25% 23% 6% 1	2786
	21st to end	Night	49% 12% 18% 15% 5% 1	3258
August	1st to 10th	Night	20% 9% 13% 35% 20% 2	3132
	11th to 20th	Night	26% 9% 18% 29% 15% 3	3130
	21st to end	Night	29% 7% 14% 21% 24% 5%	3476
September	1st to 10th	Night	37% 7% 16% 18% 16% 6%	1900
	11th to 20th	Night	34% 9% 13% 18% 19% 6%	2076
	21st to end	Night	30% 6% 10% 24% 22% 8%	2090
October	1st to 10th	Night	21% 4 5% 15% 26% 29%	3480
	11th to 20th	Night	17% 3 5% 15% 29% 31%	3541
	21st to end	Night	23% 2 4 20% 32% 19%	4244
November	1st to 10th	Night	28% 5% 8% 17% 28% 15%	2470
	11th to 20th	Night	31% 4 6% 18% 27% 13%	2470
	21st to end	Night	36% 4 7% 20% 22% 10%	2470
December	1st to 10th	Night	42% 6% 9% 17% 21% 4	2470
	11th to 20th	Night	41% 4 6% 14% 28% 6%	3044
	21st to end	Night	42% 6% 10% 18% 21% 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	23% 20% 34% 18% 5%	270
	11th to 20th	Day	23% 21% 31% 16% 7% 1	270
	21st to end	Day	23% 24% 33% 16% 2 1	297
February	1st to 10th	Day	24% 22% 32% 17% 6%	270
	11th to 20th	Day	36% 14% 32% 15% 2 1	270
	21st to end	Day	31% 23% 32% 14%	225
March	1st to 10th	Day	23% 21% 34% 16% 6% 1	270
	11th to 20th	Day	20% 17% 35% 19% 8%	327
	21st to end	Day	22% 16% 29% 22% 10% 1	506
April	1st to 10th	Day	18% 16% 30% 23% 12% 1	460
	11th to 20th	Day	15% 15% 30% 24% 13% 3	452
	21st to end	Day	11% 13% 29% 31% 15% 2	460
May	1st to 10th	Day	13% 7% 25% 32% 17% 6%	463
	11th to 20th	Day	11% 4 24% 28% 22% 12%	487
	21st to end	Day	10% 3 22% 30% 21% 14%	529
June	1st to 10th	Day	12% 4 14% 29% 24% 16%	490
	11th to 20th	Day	7% 2 13% 23% 33% 22%	490
	21st to end	Day	8% 2 10% 28% 32% 19%	567
July	1st to 10th	Day	7% 2 7% 24% 36% 23%	552
	11th to 20th	Day	7% 2 5% 20% 31% 34%	484
	21st to end	Day	8% 2 8% 19% 36% 28%	532
August	1st to 10th	Day	9% 1 7% 22% 33% 27%	486
	11th to 20th	Day	9% 1 7% 25% 37% 22%	479
	21st to end	Day	15% 1 7% 23% 29% 24%	539
September	1st to 10th	Day	10% 2 9% 29% 36% 14%	490
	11th to 20th	Day	13% 2 13% 22% 35% 13%	490
	21st to end	Day	9% 5% 15% 27% 31% 13%	490
October	1st to 10th	Day	10% 5% 20% 32% 24% 9%	490
	11th to 20th	Day	9% 6% 26% 36% 21% 2	443
	21st to end	Day	16% 12% 22% 28% 19% 2	330
November	1st to 10th	Day	19% 6% 30% 31% 10% 4	282
	11th to 20th	Day	17% 9% 40% 25% 7% 1	270
	21st to end	Day	14% 15% 34% 22% 12% 2	270
December	1st to 10th	Day	26% 16% 30% 22% 6% 1	270
	11th to 20th	Day	23% 14% 36% 17% 7% 1	270
	21st to end	Day	29% 14% 31% 20% 5% 1	297
January	1st to 10th	Night	23% 13% 32% 26% 6%	760
	11th to 20th	Night	21% 14% 29% 27% 9%	760
	21st to end	Night	20% 13% 36% 28% 3	836
February	1st to 10th	Night	21% 11% 31% 31% 5%	760
	11th to 20th	Night	25% 12% 30% 28% 4	743
	21st to end	Night	22% 15% 35% 25% 2	628
March	1st to 10th	Night	20% 11% 31% 30% 8%	760
	11th to 20th	Night	16% 10% 36% 27% 10% 1	760
	21st to end	Night	16% 12% 32% 28% 12%	657
April	1st to 10th	Night	13% 12% 32% 30% 13%	570
	11th to 20th	Night	15% 9% 31% 30% 14% 2	563
	21st to end	Night	10% 10% 28% 36% 14% 2	570
May	1st to 10th	Night	10% 5% 26% 36% 21% 3	570
	11th to 20th	Night	12% 3 21% 32% 28% 4	561
	21st to end	Night	7% 2 12% 35% 36% 7%	617
June	1st to 10th	Night	8% 3 10% 37% 36% 6%	570
	11th to 20th	Night	5% 1 9% 30% 43% 11%	570
	21st to end	Night	7% 1 7% 30% 43% 12%	570
July	1st to 10th	Night	6% 1 5% 25% 47% 16%	555
	11th to 20th	Night	5% 1 7% 23% 43% 22%	552
	21st to end	Night	7% 1 7% 26% 45% 16%	624
August	1st to 10th	Night	5% 5% 23% 50% 18%	567
	11th to 20th	Night	8% 4 30% 45% 12%	564
	21st to end	Night	11% 1 9% 25% 40% 14%	627
September	1st to 10th	Night	11% 1 10% 29% 39% 9%	570
	11th to 20th	Night	14% 3 12% 28% 37% 7%	746
	21st to end	Night	9% 2 12% 35% 38% 4	760
October	1st to 10th	Night	9% 3 20% 34% 30% 5%	760
	11th to 20th	Night	12% 5% 22% 37% 23% 1	760
	21st to end	Night	17% 6% 17% 37% 21% 2	836
November	1st to 10th	Night	13% 6% 20% 36% 22% 4	760
	11th to 20th	Night	13% 7% 28% 36% 14% 2	760
	21st to end	Night	16% 9% 29% 34% 11% 2	760
December	1st to 10th	Night	21% 9% 27% 31% 11%	760
	11th to 20th	Night	24% 8% 29% 29% 11%	760
	21st to end	Night	24% 10% 30% 30% 6%	836

Page generated at 2024-11-03 01:11:30. Version ac07

Copyright © 2024 Attilla Danko.