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 2005-11-05 to 2017-09-17.

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 TypeMinimum conditions for hour to be usableOut of hours
Clear of CloudsTransparencySeeingSky Brightness
Planetary:50%(no limit)Average(no limit)Nighttime Hours
Deep Sky:70%Average(no limit)5.9Nighttime Hours
CCD Imaging:70%Below AveragePoor(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

PlanetaryData
Pts
Deep Sky
Max 60%
Data
Pts
Both Planetary and Deep Sky
Max 60%
Data
Pts
Either Planetary or Deep SkyData
Pts
CCD ImagingData
Pts
Night
34%
15189
20%
46879
10%
15151
45%
15151
22%
29642

By Month

MonthDays of MonthPlanetaryData
Pts
Deep Sky
Max 60%
Data
Pts
Both Planetary and Deep Sky
Max 60%
Data
Pts
Either Planetary or Deep SkyData
Pts
CCD ImagingData
Pts
January1st to 15thNight
22%
718
21%
2464
8%
716
38%
716
17%
1545
January16th to endNight
18%
768
22%
2496
7%
768
38%
768
19%
1553
February1st to 15thNight
19%
703
18%
2287
5%
701
36%
701
18%
1419
February16th to endNight
19%
631
25%
1894
6%
631
40%
631
20%
1187
March1st to 15thNight
25%
720
21%
2040
9%
720
38%
720
23%
1301
March16th to endNight
24%
768
20%
2064
7%
768
35%
768
23%
1385
April1st to 15thNight
23%
718
19%
1796
5%
718
32%
718
26%
1194
April16th to endNight
34%
720
19%
1800
5%
720
41%
720
26%
1196
May1st to 15thNight
32%
543
17%
1623
8%
543
39%
543
18%
1100
May16th to endNight
43%
374
16%
1497
12%
374
52%
374
17%
900
June1st to 15thNight
46%
360
18%
1440
17%
360
55%
360
22%
840
June16th to endNight
50%
360
16%
1440
13%
360
60%
360
21%
843
July1st to 15thNight
53%
340
12%
1360
14%
340
55%
340
16%
879
July16th to endNight
60%
491
15%
1524
12%
460
67%
460
29%
888
August1st to 15thNight
57%
554
17%
1624
11%
551
59%
551
27%
1024
August16th to endNight
60%
764
18%
1910
10%
764
61%
764
31%
1276
September1st to 15thNight
53%
720
24%
1800
14%
720
57%
720
31%
1205
September16th to endNight
50%
665
21%
1815
15%
665
55%
665
26%
1204
October1st to 15thNight
40%
660
22%
1980
19%
660
49%
660
24%
1276
October16th to endNight
34%
704
27%
2112
13%
704
51%
704
29%
1250
November1st to 15thNight
32%
700
24%
2260
13%
700
48%
700
24%
1367
November16th to endNight
27%
720
20%
2445
10%
720
42%
720
18%
1493
December1st to 15thNight
23%
720
18%
2520
6%
720
38%
720
14%
1621
December16th to endNight
20%
768
21%
2688
7%
768
38%
768
16%
1696

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 ForecastData
Points
Cloud CoverDay
13%5%244245%6%8%43%
47892
Night
14%5%2442445%7%44%
47059
Cloud CoverDay
13%5%244245%5%8%43%
47902
Night
14%5%2442445%7%43%
47064
TransparencyDay
37%7%13%23%15%2
47591
Night
39%6%11%22%16%3
46879
SeeingDay
16%13%21%24%17%6%
5707
Night
15%20%24%25%13%1
15193

By Month

Percentage Cloud Cover NE (2006-)
Color Meanings:
Overcast 90% covered 80% covered 70% covered 60% covered 50% covered 40% covered 30% covered 20% covered 10% covered Clear
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
17%6%2432445%7%42%
1471
16th to endDay
14%6%25%434347%43%
1728
February1st to 15thDay
14%6%25%5%3346%6%41%
1575
16th to endDay
13%7%35%42345%6%42%
1577
March1st to 15thDay
15%5%25%414446%45%
1906
16th to endDay
17%7%24424446%41%
2160
April1st to 15thDay
14%5%2342445%6%44%
2152
16th to endDay
15%42442345%6%45%
2160
May1st to 15thDay
16%5%235%345%5%8%38%
2338
16th to endDay
13%414435%5%7%8%40%
2618
June1st to 15thDay
12%3245%25%6%7%11%40%
2520
16th to endDay
10%3234346%6%10%44%
2520
July1st to 15thDay
7%425%5%35%6%7%10%41%
2520
16th to endDay
5%214445%7%8%12%41%
2536
August1st to 15thDay
10%4245%35%6%6%9%40%
2313
16th to endDay
10%4144246%8%8%44%
2292
September1st to 15thDay
13%31442445%7%47%
2160
16th to endDay
14%5%25%42445%7%43%
1851
October1st to 15thDay
18%5%13312447%46%
1650
16th to endDay
14%5%2432335%6%47%
1760
November1st to 15thDay
15%6%133235%46%47%
1597
16th to endDay
17%5%2442335%6%44%
1512
December1st to 15thDay
17%5%2441345%7%42%
1440
16th to endDay
18%6%24435%347%39%
1536
January1st to 15thNight
17%5%2443435%7%41%
2464
16th to endNight
17%5%24424346%44%
2496
February1st to 15thNight
15%5%25%5%34346%43%
2285
16th to endNight
14%6%24324446%46%
1894
March1st to 15thNight
16%5%23323447%45%
2028
16th to endNight
15%5%35%424446%42%
2064
April1st to 15thNight
15%5%33435%35%7%44%
1796
16th to endNight
16%5%13423346%46%
1800
May1st to 15thNight
20%5%24424347%39%
1623
16th to endNight
14%5%15%43345%8%42%
1495
June1st to 15thNight
12%424425%46%8%45%
1440
16th to endNight
9%4346%35%5%5%9%43%
1440
July1st to 15thNight
10%426%6%37%7%7%7%36%
1440
16th to endNight
5%3235%36%7%5%11%45%
1629
August1st to 15thNight
10%4145%35%6%5%8%44%
1635
16th to endNight
11%6%134245%5%9%44%
1910
September1st to 15thNight
11%6%25%423445%47%
1800
16th to endNight
14%5%25%5%2435%8%43%
1815
October1st to 15thNight
19%42342345%6%44%
1980
16th to endNight
16%312323347%51%
2112
November1st to 15thNight
14%6%35%32234450%
2260
16th to endNight
16%5%2442335%7%43%
2445
December1st to 15thNight
17%5%25%5%3445%6%39%
2520
16th to endNight
17%5%245%2435%7%41%
2688

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
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
17%5%2442335%7%42%
1471
16th to endDay
14%6%25%334447%43%
1728
February1st to 15thDay
14%6%15%5%3345%6%41%
1575
16th to endDay
13%7%35%424447%42%
1577
March1st to 15thDay
15%5%34424447%44%
1917
16th to endDay
17%6%25%434445%41%
2159
April1st to 15thDay
14%5%2442445%6%44%
2152
16th to endDay
16%424423447%45%
2160
May1st to 15thDay
16%5%245%245%6%7%39%
2338
16th to endDay
13%4135%35%5%6%9%40%
2618
June1st to 15thDay
11%324435%5%7%10%41%
2520
16th to endDay
10%323335%5%6%9%45%
2520
July1st to 15thDay
7%425%435%6%7%10%42%
2520
16th to endDay
5%314445%7%9%12%42%
2536
August1st to 15thDay
10%4245%35%6%6%9%41%
2313
16th to endDay
9%4244246%8%8%44%
2292
September1st to 15thDay
12%414424448%47%
2160
16th to endDay
14%5%2433436%7%43%
1851
October1st to 15thDay
18%413313347%47%
1650
16th to endDay
14%5%15%323447%47%
1760
November1st to 15thDay
14%6%134245%46%46%
1597
16th to endDay
17%5%3442335%6%44%
1512
December1st to 15thDay
17%5%2432345%8%42%
1440
16th to endDay
19%6%23424446%39%
1536
January1st to 15thNight
17%5%24434347%41%
2464
16th to endNight
17%5%24424445%44%
2496
February1st to 15thNight
14%5%25%5%34346%43%
2278
16th to endNight
15%6%24334346%46%
1894
March1st to 15thNight
16%5%13414447%45%
2040
16th to endNight
15%6%35%5%2445%5%43%
2064
April1st to 15thNight
15%5%24434447%43%
1796
16th to endNight
16%5%23323347%45%
1800
May1st to 15thNight
20%6%244245%37%39%
1623
16th to endNight
13%6%235%2436%8%42%
1495
June1st to 15thNight
11%425%4345%5%7%46%
1440
16th to endNight
9%4245%35%45%9%43%
1440
July1st to 15thNight
9%5%26%6%36%7%7%7%36%
1440
16th to endNight
6%2245%36%7%6%11%43%
1629
August1st to 15thNight
9%4245%35%6%5%9%43%
1635
16th to endNight
11%5%244345%6%8%44%
1910
September1st to 15thNight
11%6%24424446%47%
1800
16th to endNight
14%6%25%42345%8%42%
1815
October1st to 15thNight
18%5%2442425%5%44%
1980
16th to endNight
16%312323437%51%
2112
November1st to 15thNight
14%6%35%32234450%
2260
16th to endNight
16%5%25%42345%6%43%
2445
December1st to 15thNight
17%5%25%5%25%45%6%39%
2520
16th to endNight
17%5%25%5%2435%7%40%
2688

Transparency (when cloud cover <= 30%)
Color Meanings:
Too cloudy to forecast Poor Below Average Average Above average Transparent
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
40%5%15%22%12%4
1472
16th to endDay
40%5%12%23%14%3
1728
February1st to 15thDay
40%5%12%26%12%2
1577
16th to endDay
41%412%26%13%1
1577
March1st to 15thDay
39%5%13%24%15%2
1917
16th to endDay
43%5%10%19%18%2
2160
April1st to 15thDay
39%5%11%21%17%4
2152
16th to endDay
37%6%10%18%20%5%
2160
May1st to 15thDay
40%8%14%20%14%2
2338
16th to endDay
37%8%16%23%12%1
2622
June1st to 15thDay
34%10%14%25%13%1
2520
16th to endDay
31%11%15%21%18%1
2520
July1st to 15thDay
32%10%16%21%14%3
2371
16th to endDay
29%11%18%25%13%1
2379
August1st to 15thDay
36%8%15%22%15%1
2300
16th to endDay
32%9%13%23%16%3
2292
September1st to 15thDay
34%7%14%20%19%3
2160
16th to endDay
40%6%9%20%21%2
1851
October1st to 15thDay
36%413%25%17%3
1650
16th to endDay
35%411%28%19%1
1760
November1st to 15thDay
37%413%21%18%4
1597
16th to endDay
40%410%26%15%2
1512
December1st to 15thDay
40%5%16%24%11%3
1440
16th to endDay
44%5%11%23%13%
1536
January1st to 15thNight
42%5%11%20%17%3
2464
16th to endNight
40%411%25%15%1
2496
February1st to 15thNight
41%412%24%15%2
2287
16th to endNight
39%49%24%19%2
1894
March1st to 15thNight
38%5%13%25%14%2
2040
16th to endNight
42%5%12%19%17%3
2064
April1st to 15thNight
38%5%11%20%19%3
1796
16th to endNight
38%6%10%19%19%6%
1800
May1st to 15thNight
44%6%10%20%14%2
1623
16th to endNight
37%8%16%18%14%3
1497
June1st to 15thNight
36%7%13%25%17%
1440
16th to endNight
35%8%12%24%16%2
1440
July1st to 15thNight
42%10%15%16%11%3
1360
16th to endNight
29%10%17%23%17%1
1524
August1st to 15thNight
35%8%14%21%18%1
1624
16th to endNight
37%7%12%21%18%3
1910
September1st to 15thNight
37%7%9%21%19%4
1800
16th to endNight
40%5%9%18%20%4
1815
October1st to 15thNight
41%49%23%16%3
1980
16th to endNight
33%5%9%28%20%2
2112
November1st to 15thNight
37%48%22%17%7%
2260
16th to endNight
39%5%11%22%17%3
2445
December1st to 15thNight
44%5%10%22%13%1
2520
16th to endNight
41%6%13%22%13%2
2688

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
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
29%13%38%11%41
67
16th to endDay
20%20%36%15%6%
96
February1st to 15thDay
20%20%38%17%3
90
16th to endDay
18%18%38%20%3
236
March1st to 15thDay
15%21%30%26%4
270
16th to endDay
19%19%29%24%33
288
April1st to 15thDay
16%20%30%20%10%2
270
16th to endDay
19%14%23%20%15%5%
270
May1st to 15thDay
25%21%24%16%9%3
288
16th to endDay
19%11%16%22%21%7%
331
June1st to 15thDay
12%12%19%22%24%8%
315
16th to endDay
9%11%21%34%16%6%
315
July1st to 15thDay
9%7%12%35%27%7%
305
16th to endDay
5%10%8%33%32%10%
326
August1st to 15thDay
14%6%11%27%29%11%
313
16th to endDay
8%5%9%29%31%15%
332
September1st to 15thDay
11%7%20%21%22%16%
315
16th to endDay
23%7%11%28%18%10%
259
October1st to 15thDay
23%9%15%25%19%5%
255
16th to endDay
13%12%29%28%14%1
272
November1st to 15thDay
17%15%30%16%14%5%
238
16th to endDay
18%20%25%20%11%3
132
December1st to 15thDay
16%18%35%16%11%1
60
16th to endDay
31%7%34%18%7%
64
January1st to 15thNight
15%28%29%21%4
720
16th to endNight
18%25%34%20%1
768
February1st to 15thNight
15%27%32%22%1
704
16th to endNight
16%28%32%19%2
631
March1st to 15thNight
17%25%29%22%4
720
16th to endNight
16%22%32%20%6%1
768
April1st to 15thNight
16%23%33%21%5%
718
16th to endNight
17%20%24%26%10%
720
May1st to 15thNight
21%21%20%25%8%
543
16th to endNight
14%20%15%30%20%
375
June1st to 15thNight
10%17%18%30%22%
360
16th to endNight
7%18%15%41%16%1
360
July1st to 15thNight
10%13%13%32%28%
340
16th to endNight
6%16%9%34%29%3
491
August1st to 15thNight
12%10%11%36%26%2
554
16th to endNight
12%8%10%32%29%5%
764
September1st to 15thNight
11%10%17%26%29%3
720
16th to endNight
17%10%13%27%25%5%
665
October1st to 15thNight
20%13%19%26%18%2
660
16th to endNight
15%16%30%23%13%
704
November1st to 15thNight
16%20%26%22%12%1
700
16th to endNight
15%27%26%22%7%
720
December1st to 15thNight
17%25%28%19%9%
720
16th to endNight
17%25%33%20%2
768
Page generated at 2017-09-18 08:38:25. Version ac04

Copyright 2017 A. Danko


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