Huronia Star Party
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Huronia Star Party 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
31%
14923
11%
46645
8%
14887
35%
14887
14%
34859

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
9%
810
3%
2557
1%
809
12%
809
4%
2248
January16th to endNight
16%
768
4%
2496
2%
768
19%
768
5%
2191
February1st to 15thNight
15%
701
4%
2287
1%
701
19%
701
6%
1939
February16th to endNight
21%
631
8%
2006
2%
631
28%
631
9%
1592
March1st to 15thNight
19%
720
10%
1995
5%
720
23%
720
14%
1563
March16th to endNight
32%
768
18%
2112
10%
768
39%
768
21%
1506
April1st to 15thNight
26%
702
13%
1819
5%
702
30%
702
20%
1337
April16th to endNight
36%
540
18%
1620
11%
540
41%
540
21%
1112
May1st to 15thNight
48%
504
15%
1584
13%
504
52%
504
23%
1044
May16th to endNight
47%
374
16%
1497
15%
374
56%
374
24%
857
June1st to 15thNight
46%
360
11%
1371
11%
360
53%
360
20%
859
June16th to endNight
51%
360
13%
1260
14%
360
55%
360
26%
761
July1st to 15thNight
60%
340
17%
1206
20%
340
64%
340
36%
640
July16th to endNight
56%
499
15%
1531
15%
467
59%
467
28%
918
August1st to 15thNight
62%
539
15%
1609
11%
536
64%
536
31%
962
August16th to endNight
59%
597
19%
1743
13%
597
62%
597
30%
1087
September1st to 15thNight
51%
720
16%
1839
9%
720
53%
720
32%
1214
September16th to endNight
52%
665
19%
1842
14%
665
54%
665
28%
1211
October1st to 15thNight
34%
660
14%
1980
12%
660
39%
660
18%
1426
October16th to endNight
19%
704
7%
2120
4%
704
23%
704
9%
1744
November1st to 15thNight
25%
700
13%
2390
11%
700
30%
700
12%
1788
November16th to endNight
21%
720
8%
2520
5%
720
25%
720
7%
2094
December1st to 15thNight
10%
720
2%
2520
1%
720
11%
720
3%
2260
December16th to endNight
8%
821
2%
2741
0%
821
10%
821
2%
2506

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
14%9%48%7%35%5%5%7%28%
48125
Night
13%9%48%7%35%5%5%6%29%
46817
Cloud CoverDay
14%9%47%6%35%5%5%7%29%
48135
Night
13%9%47%6%35%5%5%6%30%
46821
TransparencyDay
52%8%12%16%8%
47815
Night
53%9%12%15%8%
46645
SeeingDay
17%9%27%26%13%5%
5689
Night
18%13%29%26%10%1
14931

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
13%12%8%14%11%5%6%6%4410%
1372
16th to endDay
8%16%7%13%15%6%8%5%45%9%
1728
February1st to 15thDay
12%13%8%14%12%6%5%6%5%410%
1575
16th to endDay
15%15%5%10%9%5%6%5%4416%
1467
March1st to 15thDay
12%11%6%9%10%45%5%5%5%24%
1954
16th to endDay
12%10%47%7%35%45%6%31%
2112
April1st to 15thDay
16%12%47%6%3445%6%29%
2139
16th to endDay
16%8%46%5%2345%6%36%
2340
May1st to 15thDay
16%8%26%6%3445%7%34%
2367
16th to endDay
12%7%25%5%3446%8%39%
2618
June1st to 15thDay
17%5%24425%5%7%8%35%
2586
16th to endDay
13%6%245%45%5%6%9%36%
2700
July1st to 15thDay
10%5%35%5%35%5%6%9%38%
2682
16th to endDay
10%6%36%6%35%5%6%9%35%
2528
August1st to 15thDay
10%6%26%5%45%6%7%8%37%
2340
16th to endDay
10%5%37%6%46%6%7%8%34%
2447
September1st to 15thDay
17%7%36%5%3445%7%34%
2120
16th to endDay
15%5%37%6%3345%8%35%
1824
October1st to 15thDay
18%10%37%6%3445%6%29%
1650
16th to endDay
23%15%48%6%35%45%5%16%
1752
November1st to 15thDay
13%14%47%7%345%46%26%
1468
16th to endDay
15%14%7%12%8%46%6%5%6%12%
1440
December1st to 15thDay
13%17%10%14%9%46%45%5%8%
1440
16th to endDay
16%17%8%14%9%35%445%8%
1476
January1st to 15thNight
14%13%7%13%11%5%6%5%5%6%10%
2557
16th to endNight
10%10%5%14%13%6%7%7%5%6%12%
2496
February1st to 15thNight
11%13%6%10%10%5%7%6%5%6%15%
2285
16th to endNight
10%11%5%11%9%5%7%5%5%6%21%
2006
March1st to 15thNight
14%12%5%9%7%4445%6%26%
1983
16th to endNight
11%8%5%7%5%3445%5%37%
2112
April1st to 15thNight
15%10%5%6%5%3435%5%32%
1819
16th to endNight
14%10%36%5%35%346%37%
1620
May1st to 15thNight
14%6%35%435%45%7%38%
1584
16th to endNight
12%6%2443346%8%45%
1495
June1st to 15thNight
14%5%25%435%5%6%8%39%
1371
16th to endNight
10%5%145%25%5%5%9%43%
1260
July1st to 15thNight
6%5%24423448%54%
1277
16th to endNight
8%3245%345%7%7%47%
1637
August1st to 15thNight
6%4135%35%5%7%9%46%
1620
16th to endNight
8%425%5%33448%49%
1743
September1st to 15thNight
14%42442345%9%45%
1839
16th to endNight
14%6%24424447%44%
1842
October1st to 15thNight
17%6%35%5%345%5%6%34%
1980
16th to endNight
19%16%37%6%35%5%5%6%19%
2120
November1st to 15thNight
14%13%47%5%45%5%6%6%27%
2390
16th to endNight
16%13%7%9%6%35%46%7%19%
2520
December1st to 15thNight
15%15%7%12%8%5%6%5%5%411%
2520
16th to endNight
17%13%10%16%9%45%4448%
2741

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
14%12%8%14%11%5%6%5%45%12%
1372
16th to endDay
9%15%5%13%14%5%9%5%5%411%
1728
February1st to 15thDay
11%14%8%13%11%5%6%5%5%5%12%
1575
16th to endDay
15%15%5%9%8%5%6%5%35%18%
1467
March1st to 15thDay
13%10%5%9%9%45%445%25%
1965
16th to endDay
12%9%47%6%35%5%46%33%
2111
April1st to 15thDay
16%11%46%6%2435%6%30%
2139
16th to endDay
16%8%35%5%2335%7%37%
2340
May1st to 15thDay
17%8%26%5%34447%35%
2367
16th to endDay
12%6%25%5%345%5%8%40%
2618
June1st to 15thDay
17%4244246%7%8%36%
2586
16th to endDay
13%5%245%45%5%6%8%37%
2700
July1st to 15thDay
10%5%345%35%46%9%40%
2682
16th to endDay
11%6%26%5%35%6%6%9%36%
2528
August1st to 15thDay
10%5%35%6%35%6%7%9%38%
2340
16th to endDay
11%425%6%36%6%6%8%36%
2447
September1st to 15thDay
17%6%36%5%34447%36%
2120
16th to endDay
16%427%5%35%45%7%37%
1824
October1st to 15thDay
19%8%36%7%34447%30%
1650
16th to endDay
24%14%47%6%35%5%46%17%
1752
November1st to 15thDay
13%14%47%7%345%5%7%27%
1468
16th to endDay
15%14%6%11%8%46%6%5%6%14%
1440
December1st to 15thDay
14%17%8%13%9%45%45%5%9%
1440
16th to endDay
17%17%9%12%8%35%346%10%
1476
January1st to 15thNight
14%14%6%13%10%5%5%5%5%6%13%
2557
16th to endNight
10%10%6%13%12%5%8%6%5%5%14%
2496
February1st to 15thNight
10%13%5%10%10%5%7%6%5%6%17%
2278
16th to endNight
10%11%411%9%46%5%6%7%22%
2006
March1st to 15thNight
14%12%5%9%6%44445%27%
1995
16th to endNight
11%9%47%5%34445%38%
2112
April1st to 15thNight
15%10%5%5%5%44446%33%
1819
16th to endNight
13%10%35%5%34346%38%
1620
May1st to 15thNight
14%5%345%346%5%7%39%
1583
16th to endNight
12%4235%235%5%8%46%
1495
June1st to 15thNight
14%424435%5%5%8%40%
1371
16th to endNight
11%41442445%9%45%
1260
July1st to 15thNight
6%413423348%55%
1277
16th to endNight
7%3135%345%6%7%48%
1637
August1st to 15thNight
6%3134345%6%10%48%
1620
16th to endNight
8%4145%33447%51%
1743
September1st to 15thNight
14%42442335%8%46%
1839
16th to endNight
14%5%24424446%45%
1842
October1st to 15thNight
17%6%35%5%35%35%6%36%
1980
16th to endNight
19%14%46%5%46%5%5%6%20%
2120
November1st to 15thNight
14%11%46%5%26%6%6%7%28%
2390
16th to endNight
16%13%6%9%6%3445%6%21%
2520
December1st to 15thNight
16%14%6%12%8%46%5%6%5%12%
2520
16th to endNight
17%13%9%15%9%45%45%410%
2741

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
75%8%8%5%1
1373
16th to endDay
75%8%7%6%1
1728
February1st to 15thDay
72%7%9%8%1
1577
16th to endDay
68%8%8%8%6%
1467
March1st to 15thDay
59%7%11%14%6%
1965
16th to endDay
50%6%12%15%13%1
2112
April1st to 15thDay
53%6%10%18%9%
2139
16th to endDay
46%6%10%21%13%1
2340
May1st to 15thDay
47%5%11%20%13%
2367
16th to endDay
40%8%13%22%13%1
2622
June1st to 15thDay
42%9%13%21%12%
2586
16th to endDay
41%8%15%21%12%
2700
July1st to 15thDay
38%8%14%23%13%1
2524
16th to endDay
43%7%13%23%9%1
2371
August1st to 15thDay
38%9%17%20%12%
2327
16th to endDay
42%9%16%21%8%
2447
September1st to 15thDay
47%7%13%21%8%1
2120
16th to endDay
45%7%14%23%8%
1824
October1st to 15thDay
54%7%10%16%9%1
1650
16th to endDay
67%9%11%8%3
1752
November1st to 15thDay
56%10%12%13%6%
1468
16th to endDay
69%10%10%7%1
1440
December1st to 15thDay
76%10%7%4
1440
16th to endDay
76%10%7%41
1476
January1st to 15thNight
71%11%9%5%2
2557
16th to endNight
68%14%9%5%1
2496
February1st to 15thNight
66%12%10%9%1
2287
16th to endNight
60%9%12%10%5%
2006
March1st to 15thNight
58%7%11%15%6%
1995
16th to endNight
47%7%9%18%15%1
2112
April1st to 15thNight
52%411%17%13%
1819
16th to endNight
46%6%10%16%17%2
1620
May1st to 15thNight
42%7%12%19%16%1
1584
16th to endNight
35%7%14%26%14%2
1497
June1st to 15thNight
40%8%12%21%15%1
1371
16th to endNight
35%8%15%25%15%
1260
July1st to 15thNight
27%6%14%28%21%1
1206
16th to endNight
32%9%13%26%15%1
1531
August1st to 15thNight
29%10%19%24%15%
1609
16th to endNight
33%9%13%27%14%1
1743
September1st to 15thNight
35%8%17%25%12%
1839
16th to endNight
38%7%14%25%12%
1842
October1st to 15thNight
48%9%12%18%10%
1980
16th to endNight
62%11%12%10%3
2120
November1st to 15thNight
54%10%13%14%6%1
2390
16th to endNight
63%11%11%9%2
2520
December1st to 15thNight
73%12%9%31
2520
16th to endNight
78%9%7%4
2741

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
11%29%37%17%2
67
16th to endDay
27%17%32%21%1
96
February1st to 15thDay
24%28%34%12%
90
16th to endDay
24%20%37%17%
81
March1st to 15thDay
17%18%34%23%5%
255
16th to endDay
21%10%31%25%10%1
288
April1st to 15thDay
23%11%35%17%8%2
270
16th to endDay
24%14%24%17%14%5%
270
May1st to 15thDay
20%10%24%24%14%5%
288
16th to endDay
16%6%32%24%16%4
331
June1st to 15thDay
19%8%24%27%17%2
381
16th to endDay
14%6%27%34%14%3
495
July1st to 15thDay
13%5%24%33%15%7%
458
16th to endDay
8%425%34%17%9%
326
August1st to 15thDay
9%222%30%22%12%
313
16th to endDay
12%220%30%22%10%
332
September1st to 15thDay
12%5%22%24%22%13%
315
16th to endDay
17%5%18%27%22%8%
259
October1st to 15thDay
18%8%29%29%10%3
255
16th to endDay
34%18%25%18%3
264
November1st to 15thDay
14%15%30%26%9%2
71
16th to endDay
30%20%31%16%1
60
December1st to 15thDay
21%31%25%16%5%
60
16th to endDay
26%28%43%1
64
January1st to 15thNight
22%24%32%15%4
814
16th to endNight
14%17%38%23%5%
768
February1st to 15thNight
17%20%38%19%3
704
16th to endNight
18%15%36%25%4
631
March1st to 15thNight
21%17%34%21%4
720
16th to endNight
17%11%32%26%10%1
768
April1st to 15thNight
22%13%32%25%5%
702
16th to endNight
20%10%26%28%12%1
540
May1st to 15thNight
17%6%22%37%13%2
504
16th to endNight
15%229%37%14%
375
June1st to 15thNight
17%5%24%35%16%
360
16th to endNight
13%324%39%18%1
360
July1st to 15thNight
8%221%44%22%1
340
16th to endNight
8%324%41%21%1
499
August1st to 15thNight
8%219%41%26%2
539
16th to endNight
11%319%37%24%3
597
September1st to 15thNight
15%423%30%17%8%
720
16th to endNight
17%7%18%33%18%4
665
October1st to 15thNight
20%11%29%24%12%2
660
16th to endNight
29%17%29%18%4
704
November1st to 15thNight
20%16%32%20%9%1
700
16th to endNight
24%21%29%18%5%
720
December1st to 15thNight
23%23%35%15%2
720
16th to endNight
24%20%36%15%1
821
Page generated at 2017-09-18 08:38:19. Version ac04

Copyright 2017 A. Danko


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