Martin State Airport
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Martin State Airport clear sky chart from 2005-11-06 to 2024-11-04.

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% 6% 2 5% 4 4 4 4 6% 8% 43%	101243
	Night	16% 6% 2 6% 4 4 4 3 5% 7% 42%	97727
Transparency	Day	37% 7% 13% 24% 16% 3	104877
	Night	39% 6% 12% 23% 16% 3	102233
Seeing	Day	16% 10% 25% 27% 17% 5%	14999
	Night	17% 9% 29% 30% 13% 1	24398

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	17% 5% 2 4 3 3 3 3 6% 7% 48%	2517
	11th to 20th	Day	14% 10% 3 8% 4 5% 4 3 5% 5% 40%	2780
	21st to end	Day	20% 8% 2 6% 3 4 4 3 4 7% 38%	3124
February	1st to 10th	Day	15% 6% 3 6% 5% 4 4 4 6% 7% 40%	1710
	11th to 20th	Day	17% 8% 2 5% 3 3 4 4 6% 7% 42%	1754
	21st to end	Day	18% 9% 3 7% 4 3 4 3 5% 5% 40%	1570
March	1st to 10th	Day	23% 5% 2 4 3 3 4 3 5% 7% 41%	3274
	11th to 20th	Day	10% 4 2 5% 4 4 4 4 6% 7% 49%	3480
	21st to end	Day	20% 7% 2 5% 3 4 3 3 5% 5% 43%	3941
April	1st to 10th	Day	15% 6% 2 5% 4 4 5% 4 6% 7% 42%	2280
	11th to 20th	Day	12% 6% 2 5% 4 5% 3 4 6% 7% 47%	2254
	21st to end	Day	17% 5% 2 5% 4 4 4 4 5% 8% 43%	2280
May	1st to 10th	Day	26% 8% 2 5% 4 4 4 4 5% 7% 32%	3960
	11th to 20th	Day	22% 7% 2 6% 4 4 4 4 6% 8% 31%	4398
	21st to end	Day	11% 4 2 4 4 3 5% 4 6% 9% 48%	4823
June	1st to 10th	Day	11% 4 2 5% 5% 4 5% 4 7% 11% 41%	2660
	11th to 20th	Day	11% 5% 2 5% 4 4 5% 5% 6% 9% 43%	2660
	21st to end	Day	9% 4 1 4 3 4 5% 5% 8% 10% 46%	2660
July	1st to 10th	Day	5% 4 2 6% 4 5% 6% 6% 8% 11% 44%	4440
	11th to 20th	Day	9% 5% 2 6% 4 4 5% 5% 8% 11% 41%	4440
	21st to end	Day	10% 6% 2 6% 5% 6% 6% 5% 8% 10% 37%	4498
August	1st to 10th	Day	16% 5% 2 6% 4 5% 5% 5% 7% 10% 35%	4104
	11th to 20th	Day	11% 4 2 6% 3 4 5% 4 6% 9% 44%	3804
	21st to end	Day	10% 4 2 5% 3 4 4 4 7% 8% 49%	4180
September	1st to 10th	Day	13% 5% 2 6% 4 4 4 4 4 7% 48%	2280
	11th to 20th	Day	11% 5% 1 5% 4 4 4 3 6% 8% 51%	2280
	21st to end	Day	19% 8% 3 6% 4 3 4 4 5% 8% 37%	2027
October	1st to 10th	Day	18% 5% 2 5% 3 2 3 2 5% 7% 47%	1900
	11th to 20th	Day	16% 5% 1 4 3 3 3 3 5% 6% 50%	1900
	21st to end	Day	14% 6% 2 5% 4 3 4 3 4 6% 49%	2090
November	1st to 10th	Day	13% 6% 2 4 3 2 3 4 4 7% 52%	1724
	11th to 20th	Day	14% 6% 2 3 4 4 4 4 6% 5% 49%	1710
	21st to end	Day	15% 6% 2 4 4 4 3 4 4 7% 47%	1539
December	1st to 10th	Day	18% 6% 2 5% 4 3 4 3 6% 8% 41%	1520
	11th to 20th	Day	18% 7% 2 5% 3 3 3 3 5% 8% 43%	1910
	21st to end	Day	17% 6% 2 6% 5% 5% 4 3 5% 7% 39%	2772
January	1st to 10th	Night	16% 7% 2 6% 4 4 4 3 4 6% 44%	4429
	11th to 20th	Night	19% 8% 2 5% 4 3 3 2 4 6% 44%	4175
	21st to end	Night	22% 8% 2 5% 3 3 4 3 4 5% 40%	4532
February	1st to 10th	Night	16% 7% 3 5% 5% 4 4 3 6% 6% 41%	2470
	11th to 20th	Night	18% 7% 2 6% 4 4 3 3 4 6% 43%	2310
	21st to end	Night	18% 8% 2 6% 3 4 4 3 5% 6% 42%	1884
March	1st to 10th	Night	21% 8% 2 5% 4 3 3 3 4 6% 40%	3574
	11th to 20th	Night	11% 5% 2 4 4 4 4 3 6% 7% 51%	3480
	21st to end	Night	16% 8% 2 6% 4 3 3 3 4 4 46%	3690
April	1st to 10th	Night	16% 7% 2 6% 4 4 5% 3 5% 7% 41%	1900
	11th to 20th	Night	13% 6% 3 6% 4 3 4 4 5% 6% 46%	1875
	21st to end	Night	18% 6% 2 4 3 3 3 3 5% 8% 45%	1900
May	1st to 10th	Night	24% 8% 2 6% 4 4 5% 4 4 8% 32%	2962
	11th to 20th	Night	26% 8% 3 7% 4 4 4 4 5% 6% 28%	2495
	21st to end	Night	13% 5% 2 5% 4 4 4 3 7% 10% 43%	2732
June	1st to 10th	Night	12% 5% 2 6% 4 3 4 4 5% 9% 46%	1520
	11th to 20th	Night	11% 5% 2 6% 5% 5% 5% 4 7% 8% 42%	1520
	21st to end	Night	10% 5% 2 5% 6% 4 5% 3 7% 10% 42%	1520
July	1st to 10th	Night	8% 4 2 7% 6% 5% 6% 5% 8% 9% 39%	2520
	11th to 20th	Night	10% 6% 2 6% 5% 5% 5% 5% 8% 11% 37%	2520
	21st to end	Night	13% 7% 3 7% 5% 4 6% 4 6% 8% 37%	3050
August	1st to 10th	Night	19% 5% 2 6% 5% 5% 4 5% 6% 9% 33%	2825
	11th to 20th	Night	12% 7% 3 8% 5% 6% 6% 4 7% 7% 36%	2992
	21st to end	Night	13% 5% 2 5% 3 4 4 3 5% 8% 48%	3476
September	1st to 10th	Night	13% 7% 2 6% 3 4 3 3 5% 7% 46%	1900
	11th to 20th	Night	11% 6% 2 5% 3 3 4 3 4 7% 52%	1900
	21st to end	Night	20% 7% 3 7% 4 4 3 3 5% 6% 39%	2149
October	1st to 10th	Night	20% 6% 2 6% 4 3 4 2 4 5% 43%	2280
	11th to 20th	Night	16% 5% 1 4 4 2 3 3 4 6% 52%	2280
	21st to end	Night	17% 4 1 4 3 3 4 4 4 7% 50%	2508
November	1st to 10th	Night	12% 5% 2 5% 3 3 4 3 5% 5% 53%	2424
	11th to 20th	Night	16% 6% 2 5% 3 3 2 3 5% 5% 49%	2470
	21st to end	Night	14% 5% 2 5% 4 4 4 4 6% 6% 48%	2636
December	1st to 10th	Night	18% 6% 3 6% 4 4 4 3 5% 6% 41%	2660
	11th to 20th	Night	17% 5% 2 5% 4 4 4 3 5% 7% 43%	3285
	21st to end	Night	16% 6% 3 6% 4 5% 5% 5% 7% 8% 36%	4884

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	35% 5% 10% 32% 14% 4	2518
	11th to 20th	Day	45% 5% 10% 22% 14% 4	2780
	21st to end	Day	45% 6% 14% 22% 11% 2	3124
February	1st to 10th	Day	42% 6% 14% 25% 12% 2	1710
	11th to 20th	Day	40% 5% 10% 27% 15% 3	1763
	21st to end	Day	46% 4 12% 20% 14% 4	1570
March	1st to 10th	Day	42% 6% 11% 25% 12% 3	3274
	11th to 20th	Day	30% 6% 10% 29% 20% 4	3480
	21st to end	Day	44% 6% 10% 20% 17% 4	3941
April	1st to 10th	Day	38% 8% 13% 20% 17% 5%	2280
	11th to 20th	Day	35% 6% 12% 23% 18% 6%	2254
	21st to end	Day	39% 7% 12% 20% 19% 4	2280
May	1st to 10th	Day	50% 8% 11% 20% 10% 2	3995
	11th to 20th	Day	47% 10% 17% 18% 8% 1	4402
	21st to end	Day	31% 8% 15% 26% 18% 2	4837
June	1st to 10th	Day	34% 10% 16% 24% 15% 2	2660
	11th to 20th	Day	34% 11% 13% 24% 15% 2	2660
	21st to end	Day	29% 10% 17% 25% 17% 2	2660
July	1st to 10th	Day	31% 11% 21% 19% 13% 5%	4370
	11th to 20th	Day	34% 9% 18% 27% 10% 2	4365
	21st to end	Day	39% 10% 16% 19% 15% 1	4355
August	1st to 10th	Day	42% 9% 16% 25% 8% 1	4091
	11th to 20th	Day	34% 8% 14% 29% 13% 1	3842
	21st to end	Day	30% 8% 15% 28% 16% 2	4180
September	1st to 10th	Day	35% 8% 14% 20% 18% 5%	2280
	11th to 20th	Day	32% 7% 12% 24% 22% 4	2280
	21st to end	Day	45% 6% 9% 20% 17% 2	2027
October	1st to 10th	Day	34% 5% 10% 18% 28% 5%	3160
	11th to 20th	Day	24% 4 10% 28% 26% 9%	3140
	21st to end	Day	22% 3 10% 31% 28% 5%	3428
November	1st to 10th	Day	33% 4 13% 27% 20% 3	1724
	11th to 20th	Day	35% 6% 11% 23% 22% 4	1710
	21st to end	Day	38% 5% 10% 28% 16% 2	1539
December	1st to 10th	Day	40% 5% 16% 25% 12% 2	1520
	11th to 20th	Day	39% 5% 11% 31% 11% 2	1906
	21st to end	Day	43% 7% 16% 22% 11% 1	2772
January	1st to 10th	Night	40% 6% 10% 26% 15% 3	4429
	11th to 20th	Night	41% 5% 9% 26% 16% 3	4175
	21st to end	Night	45% 5% 8% 28% 13% 1	4532
February	1st to 10th	Night	43% 5% 13% 24% 14% 1	2470
	11th to 20th	Night	43% 4 9% 21% 18% 5%	2312
	21st to end	Night	43% 4 10% 21% 17% 5%	1884
March	1st to 10th	Night	45% 5% 9% 26% 13% 2	3574
	11th to 20th	Night	31% 7% 11% 30% 17% 4	3480
	21st to end	Night	41% 5% 8% 19% 22% 5%	3690
April	1st to 10th	Night	41% 6% 11% 19% 19% 5%	1900
	11th to 20th	Night	37% 7% 12% 21% 19% 5%	1875
	21st to end	Night	39% 6% 11% 22% 17% 5%	1900
May	1st to 10th	Night	51% 8% 10% 19% 10% 2	2992
	11th to 20th	Night	52% 9% 14% 14% 10% 1	2496
	21st to end	Night	34% 10% 17% 22% 15% 3	2739
June	1st to 10th	Night	35% 8% 12% 25% 19% 2	1520
	11th to 20th	Night	37% 9% 14% 25% 14% 2	1520
	21st to end	Night	34% 9% 13% 25% 17% 3	1520
July	1st to 10th	Night	37% 10% 22% 16% 12% 3	2480
	11th to 20th	Night	36% 10% 20% 23% 9% 2	2472
	21st to end	Night	43% 8% 14% 21% 14% 1	2953
August	1st to 10th	Night	45% 8% 18% 20% 9%	2814
	11th to 20th	Night	44% 9% 13% 23% 11% 1	3020
	21st to end	Night	33% 7% 12% 29% 17% 2	3476
September	1st to 10th	Night	37% 8% 11% 21% 17% 5%	1900
	11th to 20th	Night	34% 6% 8% 25% 23% 4	1900
	21st to end	Night	46% 6% 10% 17% 18% 3	2149
October	1st to 10th	Night	43% 5% 9% 19% 20% 4	3800
	11th to 20th	Night	24% 4 11% 24% 30% 7%	3779
	21st to end	Night	23% 4 11% 32% 24% 6%	4120
November	1st to 10th	Night	33% 5% 11% 25% 20% 6%	2424
	11th to 20th	Night	37% 5% 10% 22% 20% 6%	2470
	21st to end	Night	35% 5% 12% 26% 19% 3	2636
December	1st to 10th	Night	43% 6% 11% 24% 14% 2	2660
	11th to 20th	Night	40% 6% 11% 22% 18% 4	3288
	21st to end	Night	41% 9% 15% 24% 10% 1	4884

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	21% 23% 32% 17% 7% 1	180
	11th to 20th	Day	20% 28% 29% 19% 5%	254
	21st to end	Day	17% 19% 42% 16% 5% 1	297
February	1st to 10th	Day	20% 14% 41% 18% 6%	270
	11th to 20th	Day	24% 20% 39% 14% 2	361
	21st to end	Day	24% 20% 33% 19% 4	382
March	1st to 10th	Day	16% 21% 34% 24% 4 1	460
	11th to 20th	Day	19% 19% 33% 22% 6% 1	460
	21st to end	Day	20% 15% 33% 25% 5% 2	506
April	1st to 10th	Day	18% 17% 36% 22% 5% 2	460
	11th to 20th	Day	13% 18% 30% 25% 12% 4	452
	21st to end	Day	20% 12% 30% 26% 10% 2	460
May	1st to 10th	Day	23% 13% 30% 22% 10% 2	463
	11th to 20th	Day	19% 8% 26% 29% 13% 4	487
	21st to end	Day	17% 5% 18% 27% 25% 8%	529
June	1st to 10th	Day	12% 6% 24% 27% 23% 8%	490
	11th to 20th	Day	12% 6% 18% 33% 23% 8%	490
	21st to end	Day	9% 3 21% 38% 23% 7%	490
July	1st to 10th	Day	9% 2 13% 32% 32% 13%	485
	11th to 20th	Day	4 1 9% 40% 36% 11%	484
	21st to end	Day	11% 2 16% 34% 31% 6%	532
August	1st to 10th	Day	9% 4 11% 34% 32% 9%	486
	11th to 20th	Day	11% 3 10% 33% 32% 10%	479
	21st to end	Day	9% 2 16% 30% 29% 14%	539
September	1st to 10th	Day	16% 3 17% 24% 28% 13%	490
	11th to 20th	Day	12% 2 18% 29% 27% 11%	490
	21st to end	Day	26% 7% 19% 28% 17% 3	490
October	1st to 10th	Day	21% 6% 18% 27% 20% 7%	490
	11th to 20th	Day	15% 9% 28% 27% 17% 4	490
	21st to end	Day	16% 9% 30% 27% 14% 4	539
November	1st to 10th	Day	16% 10% 32% 25% 13% 5%	387
	11th to 20th	Day	15% 15% 36% 23% 10% 1	370
	21st to end	Day	17% 18% 24% 28% 11% 2	199
December	1st to 10th	Day	18% 15% 37% 24% 5% 1	180
	11th to 20th	Day	19% 21% 29% 23% 9%	180
	21st to end	Day	21% 13% 32% 26% 8% 1	198
January	1st to 10th	Night	19% 15% 42% 21% 3	760
	11th to 20th	Night	23% 14% 33% 26% 4	760
	21st to end	Night	18% 15% 41% 24% 2	836
February	1st to 10th	Night	19% 13% 36% 28% 3	760
	11th to 20th	Night	22% 19% 39% 19% 1	743
	21st to end	Night	22% 17% 37% 20% 3	628
March	1st to 10th	Night	17% 16% 37% 26% 5%	760
	11th to 20th	Night	19% 15% 38% 22% 5% 1	760
	21st to end	Night	19% 10% 40% 24% 6% 1	836
April	1st to 10th	Night	18% 14% 41% 21% 6%	760
	11th to 20th	Night	15% 10% 34% 31% 9%	751
	21st to end	Night	20% 10% 31% 30% 9%	760
May	1st to 10th	Night	20% 9% 27% 33% 10% 1	670
	11th to 20th	Night	19% 7% 28% 34% 12%	374
	21st to end	Night	15% 4 19% 37% 23% 2	411
June	1st to 10th	Night	12% 2 24% 38% 23% 1	380
	11th to 20th	Night	9% 3 24% 40% 23% 1	380
	21st to end	Night	11% 1 18% 50% 18% 2	380
July	1st to 10th	Night	9% 3 16% 36% 33% 2	370
	11th to 20th	Night	7% 1 10% 44% 35% 3	368
	21st to end	Night	9% 3 15% 43% 30% 2	600
August	1st to 10th	Night	12% 2 13% 39% 32% 3	567
	11th to 20th	Night	12% 4 15% 37% 29% 4	681
	21st to end	Night	13% 2 15% 34% 30% 6%	836
September	1st to 10th	Night	15% 3 18% 33% 27% 5%	760
	11th to 20th	Night	13% 3 14% 36% 30% 5%	760
	21st to end	Night	22% 6% 20% 30% 20% 2	760
October	1st to 10th	Night	21% 5% 21% 29% 19% 5%	760
	11th to 20th	Night	17% 8% 28% 31% 15% 1	760
	21st to end	Night	18% 9% 30% 26% 15% 1	836
November	1st to 10th	Night	15% 6% 33% 32% 12% 2	755
	11th to 20th	Night	19% 14% 29% 29% 9% 1	760
	21st to end	Night	15% 14% 32% 29% 8% 1	760
December	1st to 10th	Night	21% 13% 36% 22% 8%	760
	11th to 20th	Night	17% 11% 41% 25% 6%	760
	21st to end	Night	19% 11% 36% 31% 3	836

Page generated at 2024-11-01 22:47:31. Version ac07

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