Mobile Regional Airport
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Mobile Regional Airport clear sky chart from 2005-11-06 to 2026-03-18.

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	11% 5% 2 6% 5% 5% 5% 4 7% 9% 42%	131004
	Night	12% 6% 2 6% 4 4 4 4 6% 8% 45%	130474
Transparency	Day	37% 6% 13% 19% 17% 8%	134853
	Night	36% 6% 13% 19% 18% 9%	134699
Seeing	Day	13% 7% 19% 24% 23% 14%	16083
	Night	13% 5% 19% 31% 26% 7%	26095

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	14% 6% 3 6% 4 4 4 3 5% 6% 46%	5796
	11th to 20th	Day	11% 4 2 5% 3 4 4 3 5% 7% 53%	5880
	21st to end	Day	22% 8% 3 6% 4 4 4 3 4 6% 37%	6436
February	1st to 10th	Day	17% 7% 2 6% 4 4 4 3 5% 5% 42%	2100
	11th to 20th	Day	17% 5% 3 5% 4 3 4 4 5% 8% 41%	2048
	21st to end	Day	16% 5% 3 6% 4 5% 5% 4 6% 7% 39%	1730
March	1st to 10th	Day	17% 8% 3 6% 4 4 4 4 5% 6% 38%	4580
	11th to 20th	Day	11% 4 2 5% 4 4 4 3 6% 7% 50%	4774
	21st to end	Day	17% 6% 2 6% 4 4 4 3 4 5% 44%	5967
April	1st to 10th	Day	12% 6% 2 5% 5% 4 4 5% 6% 7% 43%	2400
	11th to 20th	Day	12% 5% 2 6% 4 5% 4 4 6% 8% 44%	2374
	21st to end	Day	7% 6% 2 4 4 3 5% 4 6% 8% 52%	2400
May	1st to 10th	Day	13% 7% 2 7% 5% 4 5% 4 7% 9% 38%	5405
	11th to 20th	Day	11% 4 2 6% 4 5% 5% 4 7% 9% 44%	5582
	21st to end	Day	6% 4 2 6% 5% 5% 6% 4 7% 10% 45%	6433
June	1st to 10th	Day	8% 6% 2 8% 6% 7% 6% 5% 9% 10% 32%	2600
	11th to 20th	Day	5% 4 2 7% 7% 6% 8% 6% 9% 12% 35%	2600
	21st to end	Day	8% 6% 2 9% 6% 7% 7% 6% 9% 12% 28%	2600
July	1st to 10th	Day	4 5% 2 7% 7% 7% 8% 6% 10% 14% 29%	5772
	11th to 20th	Day	4 4 2 7% 6% 7% 7% 7% 11% 14% 31%	5440
	21st to end	Day	5% 5% 2 8% 6% 8% 9% 7% 11% 15% 24%	5922
August	1st to 10th	Day	4 3 1 5% 4 5% 7% 7% 10% 11% 42%	3905
	11th to 20th	Day	6% 4 2 6% 5% 6% 6% 5% 8% 11% 41%	3849
	21st to end	Day	6% 5% 3 8% 7% 7% 7% 6% 7% 10% 34%	4312
September	1st to 10th	Day	9% 6% 2 7% 5% 6% 6% 6% 9% 9% 35%	2400
	11th to 20th	Day	10% 7% 3 7% 4 5% 5% 5% 5% 8% 40%	2220
	21st to end	Day	7% 4 2 6% 4 4 5% 5% 4 6% 51%	2200
October	1st to 10th	Day	8% 5% 2 6% 4 3 4 3 4 6% 55%	2200
	11th to 20th	Day	8% 3 1 5% 3 4 4 3 5% 6% 58%	2142
	21st to end	Day	11% 4 2 4 4 3 4 3 5% 6% 54%	2200
November	1st to 10th	Day	8% 5% 2 5% 3 4 3 3 4 7% 56%	1909
	11th to 20th	Day	11% 5% 2 4 3 3 3 2 4 6% 56%	1890
	21st to end	Day	10% 5% 2 6% 5% 4 4 3 4 7% 48%	1890
December	1st to 10th	Day	16% 7% 2 6% 4 4 4 3 5% 6% 45%	3020
	11th to 20th	Day	10% 6% 2 6% 3 3 3 3 5% 6% 52%	3463
	21st to end	Day	17% 8% 2 5% 3 3 3 3 4 6% 45%	4565
January	1st to 10th	Night	15% 6% 2 6% 4 4 5% 3 5% 6% 44%	7079
	11th to 20th	Night	16% 8% 3 5% 3 3 3 2 4 6% 47%	7080
	21st to end	Night	21% 8% 3 7% 4 4 4 3 4 5% 37%	7745
February	1st to 10th	Night	14% 8% 2 5% 4 3 4 3 4 6% 46%	2520
	11th to 20th	Night	20% 7% 3 5% 4 4 4 3 4 5% 41%	2458
	21st to end	Night	16% 9% 3 6% 4 4 4 4 5% 6% 39%	2076
March	1st to 10th	Night	22% 10% 3 6% 3 3 3 3 5% 6% 37%	5493
	11th to 20th	Night	15% 7% 2 5% 4 3 4 3 5% 6% 48%	5341
	21st to end	Night	15% 6% 2 5% 3 3 4 3 5% 6% 47%	4962
April	1st to 10th	Night	14% 6% 3 6% 4 4 4 3 6% 6% 44%	2000
	11th to 20th	Night	12% 5% 2 5% 3 5% 5% 4 5% 6% 48%	1975
	21st to end	Night	6% 4 1 4 4 3 3 3 4 7% 60%	2000
May	1st to 10th	Night	14% 7% 3 7% 5% 4 4 4 6% 8% 38%	4490
	11th to 20th	Night	13% 5% 2 6% 4 4 4 3 6% 8% 45%	4308
	21st to end	Night	6% 5% 2 5% 4 5% 5% 4 7% 12% 45%	4421
June	1st to 10th	Night	6% 5% 2 7% 5% 5% 6% 5% 8% 13% 39%	1800
	11th to 20th	Night	3 4 1 4 4 6% 6% 5% 8% 11% 47%	1800
	21st to end	Night	5% 5% 2 7% 6% 7% 6% 5% 8% 12% 38%	1800
July	1st to 10th	Night	3 4 2 6% 5% 6% 7% 6% 10% 14% 36%	4166
	11th to 20th	Night	2 3 2 5% 5% 5% 6% 6% 9% 12% 46%	4517
	21st to end	Night	3 4 2 6% 5% 6% 8% 7% 10% 14% 34%	4929
August	1st to 10th	Night	2 2 1 3 3 4 5% 5% 9% 14% 51%	3244
	11th to 20th	Night	3 3 2 4 4 4 5% 5% 9% 12% 48%	3200
	21st to end	Night	4 4 3 6% 5% 6% 6% 5% 8% 11% 42%	3586
September	1st to 10th	Night	8% 5% 2 6% 5% 5% 5% 5% 8% 11% 38%	2000
	11th to 20th	Night	9% 6% 2 6% 4 5% 4 4 6% 8% 45%	2160
	21st to end	Night	7% 4 2 6% 4 4 4 3 6% 8% 51%	2200
October	1st to 10th	Night	8% 5% 2 5% 4 3 3 3 5% 8% 54%	2200
	11th to 20th	Night	7% 3 1 3 3 2 3 3 5% 6% 63%	2253
	21st to end	Night	11% 4 1 5% 3 3 3 3 4 6% 57%	2640
November	1st to 10th	Night	8% 5% 1 5% 4 4 3 3 5% 6% 57%	2606
	11th to 20th	Night	11% 5% 2 5% 3 3 3 3 5% 5% 55%	2730
	21st to end	Night	10% 5% 2 6% 3 4 4 4 6% 6% 49%	2730
December	1st to 10th	Night	13% 6% 2 6% 4 3 4 4 5% 7% 45%	4380
	11th to 20th	Night	13% 6% 2 4 3 3 4 3 4 6% 51%	4952
	21st to end	Night	18% 7% 2 6% 3 3 3 3 4 4 45%	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	39% 3 9% 18% 23% 7%	5797
	11th to 20th	Day	33% 2 4 20% 29% 12%	5880
	21st to end	Day	50% 3 6% 12% 16% 13%	6436
February	1st to 10th	Day	43% 3 8% 14% 20% 11%	2100
	11th to 20th	Day	41% 4 8% 18% 19% 10%	2058
	21st to end	Day	43% 5% 8% 17% 17% 10%	1730
March	1st to 10th	Day	45% 4 7% 18% 16% 9%	4580
	11th to 20th	Day	33% 4 8% 17% 22% 16%	4774
	21st to end	Day	43% 4 10% 19% 15% 10%	5969
April	1st to 10th	Day	38% 5% 10% 18% 19% 10%	2400
	11th to 20th	Day	37% 5% 8% 21% 21% 9%	2374
	21st to end	Day	29% 5% 10% 25% 22% 9%	2400
May	1st to 10th	Day	41% 5% 14% 24% 13% 3	5440
	11th to 20th	Day	35% 5% 18% 27% 15% 1	5586
	21st to end	Day	32% 5% 16% 32% 12% 2	6447
June	1st to 10th	Day	40% 9% 16% 24% 10% 1	2600
	11th to 20th	Day	36% 10% 17% 23% 11% 3	2600
	21st to end	Day	43% 10% 20% 18% 8% 1	2600
July	1st to 10th	Day	39% 11% 31% 16% 3	5709
	11th to 20th	Day	36% 12% 38% 12% 1	5377
	21st to end	Day	42% 13% 25% 19% 2	5752
August	1st to 10th	Day	28% 8% 19% 26% 18% 1	3893
	11th to 20th	Day	34% 7% 20% 23% 15% 1	3885
	21st to end	Day	43% 9% 18% 16% 12% 2	4311
September	1st to 10th	Day	39% 9% 18% 18% 13% 4	2400
	11th to 20th	Day	39% 8% 13% 17% 16% 6%	2220
	21st to end	Day	31% 6% 11% 23% 20% 8%	2200
October	1st to 10th	Day	30% 3 7% 12% 19% 29%	3590
	11th to 20th	Day	17% 3 4 19% 24% 33%	3473
	21st to end	Day	22% 3 4 13% 39% 19%	3538
November	1st to 10th	Day	28% 4 8% 20% 25% 15%	1909
	11th to 20th	Day	31% 2 6% 18% 29% 14%	1890
	21st to end	Day	36% 4 8% 19% 21% 12%	1890
December	1st to 10th	Day	40% 3 8% 17% 24% 8%	3020
	11th to 20th	Day	34% 3 8% 23% 21% 10%	3460
	21st to end	Day	42% 3 5% 19% 27% 5%	4565
January	1st to 10th	Night	41% 3 10% 15% 23% 8%	7080
	11th to 20th	Night	40% 2 4 16% 27% 11%	7080
	21st to end	Night	50% 3 6% 13% 19% 9%	7745
February	1st to 10th	Night	40% 3 6% 18% 22% 11%	2520
	11th to 20th	Night	46% 4 5% 14% 20% 12%	2459
	21st to end	Night	44% 6% 8% 16% 14% 13%	2076
March	1st to 10th	Night	49% 3 7% 14% 19% 8%	5493
	11th to 20th	Night	38% 4 8% 14% 20% 16%	5341
	21st to end	Night	37% 4 12% 21% 15% 11%	4962
April	1st to 10th	Night	40% 4 12% 13% 20% 11%	2000
	11th to 20th	Night	35% 4 10% 20% 22% 9%	1975
	21st to end	Night	25% 4 12% 27% 25% 8%	2000
May	1st to 10th	Night	43% 6% 16% 18% 14% 3	4520
	11th to 20th	Night	36% 5% 17% 27% 14% 1	4309
	21st to end	Night	29% 6% 19% 32% 12% 1	4429
June	1st to 10th	Night	34% 9% 22% 24% 10% 2	1800
	11th to 20th	Night	28% 8% 25% 26% 12% 1	1800
	21st to end	Night	36% 9% 25% 19% 10% 1	1800
July	1st to 10th	Night	35% 11% 33% 18% 3	4121
	11th to 20th	Night	27% 14% 42% 14% 1	4460
	21st to end	Night	36% 16% 24% 22% 2	4785
August	1st to 10th	Night	20% 9% 24% 30% 15% 1	3232
	11th to 20th	Night	24% 9% 27% 26% 13%	3230
	21st to end	Night	35% 11% 22% 18% 11% 3	3586
September	1st to 10th	Night	35% 10% 21% 18% 11% 5%	2000
	11th to 20th	Night	36% 7% 15% 19% 16% 7%	2160
	21st to end	Night	30% 6% 13% 25% 17% 9%	2200
October	1st to 10th	Night	34% 4 8% 13% 20% 21%	3590
	11th to 20th	Night	14% 2 5% 20% 26% 32%	3661
	21st to end	Night	20% 3 4 11% 42% 20%	4252
November	1st to 10th	Night	29% 3 8% 17% 27% 16%	2606
	11th to 20th	Night	31% 3 5% 19% 27% 15%	2730
	21st to end	Night	34% 4 8% 20% 22% 12%	2730
December	1st to 10th	Night	38% 3 8% 17% 23% 10%	4380
	11th to 20th	Night	35% 3 6% 23% 22% 10%	4954
	21st to end	Night	43% 2 5% 18% 25% 6%	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	20% 12% 39% 22% 7% 1	330
	11th to 20th	Day	17% 15% 33% 24% 9% 2	330
	21st to end	Day	26% 10% 39% 19% 5% 1	363
February	1st to 10th	Day	22% 15% 35% 20% 6% 1	330
	11th to 20th	Day	25% 18% 30% 19% 7%	330
	21st to end	Day	14% 22% 41% 19% 5%	273
March	1st to 10th	Day	21% 13% 35% 25% 5%	330
	11th to 20th	Day	18% 15% 36% 22% 9%	341
	21st to end	Day	17% 11% 30% 29% 12% 1	550
April	1st to 10th	Day	19% 11% 31% 24% 14% 2	500
	11th to 20th	Day	15% 12% 30% 23% 16% 4	492
	21st to end	Day	10% 8% 26% 33% 18% 5%	500
May	1st to 10th	Day	11% 5% 25% 28% 23% 7%	503
	11th to 20th	Day	10% 4 18% 31% 26% 11%	527
	21st to end	Day	8% 2 13% 36% 24% 18%	573
June	1st to 10th	Day	10% 2 9% 28% 29% 21%	530
	11th to 20th	Day	8% 3 8% 27% 31% 22%	530
	21st to end	Day	8% 2 6% 20% 34% 29%	530
July	1st to 10th	Day	8% 3 3 18% 33% 35%	525
	11th to 20th	Day	7% 3 3 12% 35% 40%	524
	21st to end	Day	6% 1 3 20% 40% 30%	576
August	1st to 10th	Day	6% 2 2 13% 40% 37%	526
	11th to 20th	Day	9% 1 2 14% 35% 39%	519
	21st to end	Day	11% 2 6% 18% 34% 30%	583
September	1st to 10th	Day	9% 2 4 22% 38% 25%	530
	11th to 20th	Day	10% 3 7% 23% 36% 20%	530
	21st to end	Day	9% 2 8% 29% 34% 17%	530
October	1st to 10th	Day	12% 2 18% 35% 24% 9%	530
	11th to 20th	Day	6% 5% 15% 31% 32% 10%	472
	21st to end	Day	15% 6% 22% 31% 19% 7%	363
November	1st to 10th	Day	14% 5% 24% 35% 18% 4	330
	11th to 20th	Day	16% 10% 26% 27% 16% 5%	330
	21st to end	Day	14% 13% 32% 27% 11% 4	330
December	1st to 10th	Day	18% 11% 34% 22% 12% 3	330
	11th to 20th	Day	19% 11% 34% 26% 9% 1	330
	21st to end	Day	23% 11% 28% 25% 12% 2	363
January	1st to 10th	Night	20% 7% 34% 32% 7%	840
	11th to 20th	Night	17% 10% 28% 35% 10%	840
	21st to end	Night	22% 10% 30% 33% 6%	924
February	1st to 10th	Night	18% 10% 31% 34% 7%	840
	11th to 20th	Night	23% 11% 31% 26% 8%	823
	21st to end	Night	21% 11% 34% 30% 5%	692
March	1st to 10th	Night	19% 9% 31% 33% 9%	840
	11th to 20th	Night	15% 9% 29% 34% 12% 1	783
	21st to end	Night	12% 6% 29% 38% 15%	660
April	1st to 10th	Night	17% 8% 24% 36% 14% 2	600
	11th to 20th	Night	15% 5% 27% 32% 20% 1	593
	21st to end	Night	8% 4 21% 42% 25% 2	600
May	1st to 10th	Night	12% 4 18% 39% 25% 2	600
	11th to 20th	Night	8% 2 12% 40% 34% 4	591
	21st to end	Night	9% 2 8% 32% 40% 9%	650
June	1st to 10th	Night	9% 1 5% 34% 43% 9%	600
	11th to 20th	Night	4 2 4 27% 48% 14%	600
	21st to end	Night	8% 1 4 21% 50% 16%	600
July	1st to 10th	Night	5% 2 1 15% 54% 24%	585
	11th to 20th	Night	3 1 1 11% 49% 35%	582
	21st to end	Night	3 2 1 18% 52% 24%	657
August	1st to 10th	Night	3 1 1 11% 52% 32%	597
	11th to 20th	Night	6% 1 1 11% 49% 31%	594
	21st to end	Night	10% 2 3 17% 50% 19%	660
September	1st to 10th	Night	9% 2 4 20% 45% 20%	600
	11th to 20th	Night	10% 3 6% 25% 45% 11%	760
	21st to end	Night	9% 2 9% 29% 42% 9%	800
October	1st to 10th	Night	12% 2 15% 36% 31% 5%	800
	11th to 20th	Night	9% 3 18% 33% 31% 6%	800
	21st to end	Night	12% 4 19% 38% 24% 3	880
November	1st to 10th	Night	11% 4 18% 42% 23% 3	820
	11th to 20th	Night	14% 5% 22% 39% 18% 2	840
	21st to end	Night	13% 6% 27% 35% 17% 2	840
December	1st to 10th	Night	16% 7% 28% 33% 14% 2	840
	11th to 20th	Night	20% 6% 26% 35% 13% 1	840
	21st to end	Night	23% 6% 30% 31% 10% 1	924

Page generated at 2026-03-15 01:23:52. Version ac07

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