Mahoney State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Mahoney State Park clear sky chart from 2005-11-05 to

2017-09-12
.

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
42%
15967
21%
46924
13%
15922
50%
15922
31%
28470

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
36%
900
20%
2327
10%
895
44%
895
30%
1518
January16th to endNight
29%
960
24%
2496
10%
960
39%
960
29%
1635
February1st to 15thNight
27%
880
12%
2288
3%
876
32%
876
23%
1642
February16th to endNight
31%
672
24%
1934
7%
672
45%
672
31%
1184
March1st to 15thNight
36%
564
22%
2004
13%
564
47%
564
26%
1177
March16th to endNight
28%
576
15%
2112
11%
576
36%
576
19%
1378
April1st to 15thNight
31%
539
20%
1869
12%
539
44%
539
24%
1131
April16th to endNight
34%
540
20%
1620
15%
540
44%
540
24%
1054
May1st to 15thNight
39%
540
18%
1620
13%
540
46%
540
25%
1053
May16th to endNight
42%
561
15%
1658
8%
561
48%
561
29%
1044
June1st to 15thNight
52%
540
17%
1440
7%
540
56%
540
36%
882
June16th to endNight
59%
540
23%
1443
10%
540
63%
540
50%
776
July1st to 15thNight
69%
510
15%
1530
10%
510
71%
510
42%
829
July16th to endNight
79%
564
25%
1594
22%
531
82%
531
52%
784
August1st to 15thNight
72%
539
21%
1610
23%
536
74%
536
41%
880
August16th to endNight
64%
573
25%
1743
27%
573
68%
573
38%
974
September1st to 15thNight
58%
530
24%
1877
23%
530
65%
530
35%
978
September16th to endNight
54%
492
29%
1815
25%
492
64%
492
37%
901
October1st to 15thNight
40%
619
27%
1939
17%
619
48%
619
30%
1139
October16th to endNight
44%
704
25%
2112
14%
704
52%
704
35%
1203
November1st to 15thNight
44%
864
28%
2264
14%
864
53%
864
41%
1312
November16th to endNight
36%
900
23%
2478
11%
900
45%
900
33%
1512
December1st to 15thNight
29%
900
17%
2520
6%
900
37%
900
25%
1691
December16th to endNight
32%
960
20%
2631
8%
960
42%
960
25%
1793

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
11%6%25%43445%7%44%
47726
Night
10%5%24423347%49%
47119
Cloud CoverDay
11%6%25%43445%7%44%
47724
Night
10%5%24423447%49%
47119
TransparencyDay
39%6%14%24%13%1
47424
Night
34%5%13%26%16%2
46924
SeeingDay
13%6%27%31%17%3
5975
Night
13%7%31%34%11%
15969

By Month

Percentage Cloud Cover SW (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
10%5%27%6%44437%43%
1611
16th to endDay
10%9%37%5%34346%40%
1728
February1st to 15thDay
11%9%5%7%6%2445%6%35%
1575
16th to endDay
12%7%36%424446%41%
1548
March1st to 15thDay
10%8%46%434447%43%
1956
16th to endDay
16%10%35%434446%36%
2112
April1st to 15thDay
16%8%35%423335%42%
2076
16th to endDay
23%7%34434346%35%
2340
May1st to 15thDay
14%6%35%5%345%46%39%
2331
16th to endDay
14%5%35%5%35%45%7%38%
2454
June1st to 15thDay
10%5%25%5%2445%7%44%
2520
16th to endDay
6%3144245%6%7%51%
2514
July1st to 15thDay
8%31443446%9%48%
2340
16th to endDay
421343446%9%54%
2466
August1st to 15thDay
6%4145%45%6%7%9%43%
2340
16th to endDay
9%4244235%5%8%49%
2459
September1st to 15thDay
12%5%2442334450%
2001
16th to endDay
9%314323336%57%
1815
October1st to 15thDay
13%5%23423345%49%
1680
16th to endDay
12%7%14423345%49%
1760
November1st to 15thDay
8%5%24323435%57%
1591
16th to endDay
11%8%445%2335%6%43%
1479
December1st to 15thDay
11%10%47%5%43446%38%
1440
16th to endDay
12%11%48%6%34436%34%
1590
January1st to 15thNight
7%6%35%5%3445%8%44%
2327
16th to endNight
9%10%36%422336%47%
2496
February1st to 15thNight
12%9%5%7%6%34346%37%
2278
16th to endNight
9%6%25%32445%6%48%
1934
March1st to 15thNight
9%7%24422346%50%
2004
16th to endNight
17%7%25%32445%7%38%
2112
April1st to 15thNight
13%6%25%323347%46%
1869
16th to endNight
18%6%15%32235%5%43%
1620
May1st to 15thNight
14%5%25%425%35%8%42%
1619
16th to endNight
13%425%5%23448%46%
1656
June1st to 15thNight
8%3134245%5%7%51%
1440
16th to endNight
221232437%8%60%
1443
July1st to 15thNight
421332346%10%55%
1620
16th to endNight
211232335%11%61%
1702
August1st to 15thNight
33125%245%5%9%55%
1620
16th to endNight
9%313423336%57%
1743
September1st to 15thNight
8%41341245%7%55%
1877
16th to endNight
7%313323345%60%
1815
October1st to 15thNight
14%424323345%51%
1939
16th to endNight
12%413313445%55%
2112
November1st to 15thNight
7%423323346%57%
2264
16th to endNight
11%6%34323346%51%
2478
December1st to 15thNight
13%8%35%5%34346%41%
2520
16th to endNight
13%10%36%5%2335%6%41%
2631

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
9%6%27%5%45%347%43%
1611
16th to endDay
10%9%47%5%34346%40%
1728
February1st to 15thDay
11%9%5%7%6%25%45%6%35%
1575
16th to endDay
12%7%36%424447%41%
1548
March1st to 15thDay
9%9%46%434446%43%
1956
16th to endDay
16%10%35%434346%35%
2110
April1st to 15thDay
16%8%35%424335%42%
2076
16th to endDay
22%7%24434446%34%
2340
May1st to 15thDay
14%6%35%5%345%5%6%39%
2331
16th to endDay
13%5%35%5%35%5%5%7%38%
2454
June1st to 15thDay
10%5%245%245%48%44%
2520
16th to endDay
6%41442446%8%51%
2514
July1st to 15thDay
8%3244345%6%9%47%
2340
16th to endDay
421343446%9%54%
2466
August1st to 15thDay
5%424436%6%7%10%43%
2340
16th to endDay
8%4144345%5%8%49%
2459
September1st to 15thDay
12%5%24423345%49%
2001
16th to endDay
9%423323346%57%
1815
October1st to 15thDay
13%5%24424445%49%
1680
16th to endDay
12%7%15%423336%49%
1760
November1st to 15thDay
8%5%24324345%56%
1591
16th to endDay
11%8%45%5%23346%43%
1479
December1st to 15thDay
11%10%47%5%34346%37%
1440
16th to endDay
13%10%48%6%24436%34%
1590
January1st to 15thNight
7%7%26%6%245%6%8%44%
2327
16th to endNight
9%9%36%423236%47%
2496
February1st to 15thNight
11%9%5%6%6%34346%37%
2278
16th to endNight
8%6%2442445%6%48%
1934
March1st to 15thNight
9%8%34422346%49%
2004
16th to endNight
16%7%35%42445%7%38%
2112
April1st to 15thNight
13%6%25%42325%6%46%
1869
16th to endNight
18%6%25%41235%6%43%
1620
May1st to 15thNight
14%5%345%25%45%7%42%
1619
16th to endNight
12%4245%23449%45%
1656
June1st to 15thNight
8%3235%25%5%5%8%51%
1440
16th to endNight
221232446%8%60%
1443
July1st to 15thNight
422332346%10%55%
1620
16th to endNight
211222436%10%61%
1702
August1st to 15thNight
33135%345%5%10%54%
1620
16th to endNight
8%324423336%57%
1743
September1st to 15thNight
8%413412447%55%
1877
16th to endNight
7%313323346%60%
1815
October1st to 15thNight
14%424323345%51%
1939
16th to endNight
12%413323445%55%
2112
November1st to 15thNight
7%423323346%57%
2264
16th to endNight
11%5%25%323346%51%
2478
December1st to 15thNight
13%8%35%424346%41%
2520
16th to endNight
13%10%36%42335%5%41%
2631

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%18%23%10%
1612
16th to endDay
45%5%16%20%11%
1728
February1st to 15thDay
48%7%17%19%7%
1576
16th to endDay
42%5%14%22%12%1
1548
March1st to 15thDay
42%5%13%23%13%1
1956
16th to endDay
50%5%15%20%7%1
2112
April1st to 15thDay
45%412%25%11%
2076
16th to endDay
50%6%10%20%10%
2340
May1st to 15thDay
44%7%11%21%14%
2331
16th to endDay
43%8%15%20%10%
2458
June1st to 15thDay
37%7%15%24%13%1
2520
16th to endDay
29%7%16%29%13%3
2514
July1st to 15thDay
31%7%15%28%12%3
2201
16th to endDay
24%8%16%30%19%1
2311
August1st to 15thDay
31%10%18%24%13%1
2326
16th to endDay
31%7%12%27%16%5%
2459
September1st to 15thDay
36%411%26%17%3
2001
16th to endDay
28%5%11%31%21%
1815
October1st to 15thDay
35%5%11%22%22%2
1680
16th to endDay
36%5%12%24%18%2
1760
November1st to 15thDay
29%414%26%23%1
1591
16th to endDay
41%5%13%28%11%
1479
December1st to 15thDay
47%5%14%22%8%1
1440
16th to endDay
51%5%13%19%10%
1590
January1st to 15thNight
36%6%16%24%14%
2327
16th to endNight
39%414%27%12%1
2496
February1st to 15thNight
49%414%20%9%1
2288
16th to endNight
33%6%14%26%15%3
1934
March1st to 15thNight
35%6%11%26%17%2
2004
16th to endNight
45%6%13%23%9%1
2112
April1st to 15thNight
39%49%27%17%1
1869
16th to endNight
42%5%12%23%15%
1620
May1st to 15thNight
40%5%11%23%16%2
1620
16th to endNight
37%6%17%23%13%1
1658
June1st to 15thNight
29%8%15%28%15%2
1440
16th to endNight
19%7%14%31%22%4
1443
July1st to 15thNight
23%7%18%28%18%4
1530
16th to endNight
17%6%16%36%20%2
1594
August1st to 15thNight
24%7%18%30%16%2
1610
16th to endNight
29%411%26%20%8%
1743
September1st to 15thNight
27%5%13%26%20%6%
1877
16th to endNight
25%5%10%31%22%4
1815
October1st to 15thNight
34%410%21%23%4
1939
16th to endNight
30%411%27%23%2
2112
November1st to 15thNight
27%413%25%25%4
2264
16th to endNight
34%314%27%18%1
2478
December1st to 15thNight
42%5%15%25%10%
2520
16th to endNight
44%5%14%22%11%1
2631

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
21%12%32%26%6%1
90
16th to endDay
20%7%41%20%8%1
96
February1st to 15thDay
15%14%44%21%4
90
16th to endDay
13%12%33%29%8%2
81
March1st to 15thDay
17%16%38%20%42
90
16th to endDay
32%6%32%22%6%
96
April1st to 15thDay
17%10%36%26%8%
195
16th to endDay
27%13%29%20%8%
450
May1st to 15thDay
17%9%33%26%13%
468
16th to endDay
17%6%33%27%13%1
517
June1st to 15thDay
11%5%24%34%21%2
495
16th to endDay
6%5%30%35%18%3
495
July1st to 15thDay
8%320%33%26%6%
475
16th to endDay
3115%46%27%4
515
August1st to 15thDay
5%116%46%25%4
493
16th to endDay
10%223%33%25%5%
499
September1st to 15thDay
9%427%36%17%4
188
16th to endDay
10%5%33%25%22%3
90
October1st to 15thDay
10%6%31%31%12%8%
90
16th to endDay
10%446%28%10%
96
November1st to 15thDay
8%5%30%32%18%4
90
16th to endDay
40%6%36%13%3
90
December1st to 15thDay
16%20%41%15%33
90
16th to endDay
25%19%36%16%2
96
January1st to 15thNight
11%10%35%34%7%
900
16th to endNight
15%9%38%30%5%
960
February1st to 15thNight
16%8%40%29%5%
880
16th to endNight
12%9%43%28%6%
672
March1st to 15thNight
13%10%35%30%9%
564
16th to endNight
20%9%38%25%6%
576
April1st to 15thNight
15%12%36%30%4
539
16th to endNight
21%9%32%28%7%
540
May1st to 15thNight
16%9%32%29%11%
540
16th to endNight
15%5%31%34%12%
563
June1st to 15thNight
10%328%43%13%
540
16th to endNight
3230%46%16%
540
July1st to 15thNight
5%18%45%28%1
510
16th to endNight
212%54%28%
564
August1st to 15thNight
316%53%23%2
539
16th to endNight
11%116%39%27%3
573
September1st to 15thNight
10%222%38%22%2
530
16th to endNight
9%231%34%20%1
492
October1st to 15thNight
16%7%31%29%11%2
619
16th to endNight
15%6%29%38%9%
704
November1st to 15thNight
9%9%32%35%10%
864
16th to endNight
15%10%35%29%9%
900
December1st to 15thNight
18%10%35%28%5%
900
16th to endNight
18%8%31%33%6%
960
Page generated at 2017-09-13 06:39:13. Version ac04

Copyright 2017 A. Danko


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