Indian Trail
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Indian Trail clear sky chart from 2005-11-05 to 2017-09-21.

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
49%
15827
22%
46941
15%
15790
56%
15790
28%
29540

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
33%
717
22%
2327
11%
716
47%
716
25%
1426
January16th to endNight
29%
768
25%
2496
13%
768
45%
768
26%
1512
February1st to 15thNight
29%
701
22%
2257
10%
701
44%
701
27%
1367
February16th to endNight
27%
631
28%
1850
11%
631
45%
631
30%
1142
March1st to 15thNight
35%
720
26%
1980
14%
720
45%
720
32%
1212
March16th to endNight
38%
768
20%
2112
11%
768
46%
768
27%
1384
April1st to 15thNight
41%
718
23%
1910
11%
718
50%
718
35%
1186
April16th to endNight
46%
658
22%
1738
12%
658
52%
658
33%
1090
May1st to 15thNight
48%
540
18%
1620
9%
540
54%
540
28%
1035
May16th to endNight
62%
561
17%
1684
13%
561
64%
561
29%
1080
June1st to 15thNight
62%
540
15%
1620
13%
540
64%
540
25%
1100
June16th to endNight
69%
540
15%
1620
12%
540
70%
540
27%
1063
July1st to 15thNight
70%
510
11%
1530
9%
510
71%
510
25%
1044
July16th to endNight
71%
564
14%
1595
12%
531
72%
531
26%
1057
August1st to 15thNight
69%
539
15%
1609
14%
536
69%
536
24%
1092
August16th to endNight
66%
679
17%
1825
13%
679
67%
679
27%
1272
September1st to 15thNight
69%
720
21%
1942
18%
720
70%
720
32%
1256
September16th to endNight
54%
681
17%
1881
14%
681
57%
681
24%
1317
October1st to 15thNight
54%
660
29%
1947
28%
660
60%
660
33%
1160
October16th to endNight
53%
704
33%
2112
24%
704
65%
704
37%
1179
November1st to 15thNight
49%
700
30%
2110
22%
700
59%
700
38%
1171
November16th to endNight
46%
720
27%
2340
21%
720
57%
720
30%
1351
December1st to 15thNight
42%
720
23%
2340
16%
720
52%
720
25%
1443
December16th to endNight
36%
768
23%
2496
17%
768
46%
768
23%
1601

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
12%5%2443445%8%43%
47915
Night
12%5%2442445%7%45%
47139
TransparencyDay
37%6%12%20%18%4
47616
Night
37%6%11%19%18%6%
46942
SeeingDay
15%5%18%24%23%12%
5668
Night
15%5%23%32%21%2
15835

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
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
17%6%25%324336%43%
1611
16th to endDay
14%6%25%323345%48%
1728
February1st to 15thDay
15%424423445%47%
1601
16th to endDay
14%5%14423346%48%
1622
March1st to 15thDay
14%423323347%49%
1980
16th to endDay
16%42431445%8%43%
2111
April1st to 15thDay
11%3133235%5%8%50%
2038
16th to endDay
14%424324446%47%
2231
May1st to 15thDay
10%5%345%345%6%8%41%
2331
16th to endDay
10%425%5%345%5%7%43%
2431
June1st to 15thDay
9%5%245%35%5%7%10%40%
2340
16th to endDay
6%4245%37%5%7%10%41%
2340
July1st to 15thDay
8%5%26%7%46%6%7%11%33%
2340
16th to endDay
6%425%6%48%7%8%11%34%
2465
August1st to 15thDay
12%5%25%5%47%6%7%11%30%
2340
16th to endDay
11%6%25%7%36%7%6%10%32%
2363
September1st to 15thDay
9%4245%345%6%8%44%
2015
16th to endDay
19%6%24325%447%38%
1872
October1st to 15thDay
17%41331233454%
1683
16th to endDay
11%31332323457%
1760
November1st to 15thDay
14%314212245%57%
1745
16th to endDay
13%5%24323345%50%
1620
December1st to 15thDay
15%7%3432335%7%44%
1620
16th to endDay
19%6%2443345%5%41%
1728
January1st to 15thNight
15%5%2442334447%
2327
16th to endNight
16%5%23324345%47%
2496
February1st to 15thNight
15%5%24323445%48%
2249
16th to endNight
13%5%14423347%48%
1850
March1st to 15thNight
13%42432335%7%49%
1980
16th to endNight
14%6%24434347%43%
2112
April1st to 15thNight
10%5%23424347%50%
1910
16th to endNight
11%4243245%5%7%47%
1738
May1st to 15thNight
10%5%35%5%245%48%43%
1619
16th to endNight
10%425%425%6%6%8%43%
1682
June1st to 15thNight
9%5%26%6%45%6%8%9%35%
1620
16th to endNight
5%4246%47%6%9%12%36%
1620
July1st to 15thNight
7%435%7%45%7%8%13%32%
1620
16th to endNight
6%325%7%46%6%8%12%35%
1703
August1st to 15thNight
8%5%25%5%46%7%7%12%33%
1620
16th to endNight
8%6%36%6%35%6%8%9%35%
1825
September1st to 15thNight
9%414435%5%5%9%45%
1942
16th to endNight
17%7%25%5%3445%5%38%
1881
October1st to 15thNight
16%5%1331234453%
1947
16th to endNight
10%41341334457%
2112
November1st to 15thNight
12%413312246%54%
2110
16th to endNight
13%423433346%50%
2340
December1st to 15thNight
14%7%2442334445%
2340
16th to endNight
19%6%24423436%42%
2496

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
42%5%7%17%21%5%
1612
16th to endDay
37%37%20%21%9%
1728
February1st to 15thDay
37%49%20%22%4
1603
16th to endDay
37%48%24%20%4
1622
March1st to 15thDay
35%5%8%22%22%6%
1980
16th to endDay
39%6%11%20%18%3
2112
April1st to 15thDay
31%412%24%23%5%
2038
16th to endDay
37%5%10%18%21%7%
2231
May1st to 15thDay
38%8%14%20%16%1
2331
16th to endDay
38%7%14%23%14%1
2435
June1st to 15thDay
37%10%15%24%11%
2340
16th to endDay
34%9%17%21%15%2
2340
July1st to 15thDay
41%10%17%18%9%2
2201
16th to endDay
37%11%19%19%9%1
2310
August1st to 15thDay
44%9%17%17%9%1
2327
16th to endDay
43%10%16%18%10%1
2363
September1st to 15thDay
35%8%14%20%17%3
2015
16th to endDay
45%6%9%17%16%5%
1872
October1st to 15thDay
33%38%23%25%4
1683
16th to endDay
30%36%20%29%9%
1760
November1st to 15thDay
30%37%19%30%9%
1745
16th to endDay
35%5%8%19%24%6%
1620
December1st to 15thDay
39%410%21%18%4
1620
16th to endDay
43%5%9%18%17%5%
1728
January1st to 15thNight
39%49%15%23%7%
2327
16th to endNight
40%36%20%21%7%
2496
February1st to 15thNight
38%38%18%23%6%
2258
16th to endNight
36%48%22%22%4
1850
March1st to 15thNight
34%410%20%21%7%
1980
16th to endNight
40%5%10%19%18%5%
2112
April1st to 15thNight
34%49%21%23%6%
1910
16th to endNight
34%6%11%19%19%8%
1738
May1st to 15thNight
37%7%13%21%16%3
1620
16th to endNight
35%10%14%25%13%1
1684
June1st to 15thNight
40%9%15%22%9%1
1620
16th to endNight
36%11%17%19%11%3
1620
July1st to 15thNight
38%12%19%18%8%3
1530
16th to endNight
36%12%19%19%9%2
1595
August1st to 15thNight
39%11%19%18%10%1
1609
16th to endNight
39%11%18%21%8%1
1825
September1st to 15thNight
34%9%15%19%15%5%
1942
16th to endNight
46%6%11%13%17%3
1881
October1st to 15thNight
35%49%19%24%6%
1947
16th to endNight
30%47%19%26%12%
2112
November1st to 15thNight
31%27%16%28%13%
2110
16th to endNight
34%46%19%26%8%
2340
December1st to 15thNight
40%39%19%19%6%
2340
16th to endNight
44%310%16%18%6%
2496

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
25%14%24%31%4
90
16th to endDay
16%23%40%13%41
96
February1st to 15thDay
15%18%52%12%1
90
16th to endDay
14%13%43%21%7%
123
March1st to 15thDay
13%11%31%32%10%
270
16th to endDay
17%8%31%29%11%1
288
April1st to 15thDay
16%10%24%25%19%3
270
16th to endDay
18%421%27%19%8%
270
May1st to 15thDay
13%6%27%26%17%8%
288
16th to endDay
16%212%21%27%19%
331
June1st to 15thDay
12%211%25%28%18%
315
16th to endDay
10%11%25%31%20%
315
July1st to 15thDay
7%10%21%37%21%
305
16th to endDay
8%16%19%39%24%
326
August1st to 15thDay
17%27%21%29%23%
313
16th to endDay
13%6%23%28%25%
332
September1st to 15thDay
13%110%22%30%20%
315
16th to endDay
23%215%22%22%13%
275
October1st to 15thDay
22%218%25%23%6%
255
16th to endDay
11%419%30%24%10%
272
November1st to 15thDay
19%5%20%27%20%6%
253
16th to endDay
6%14%18%36%21%2
90
December1st to 15thDay
22%8%37%21%10%
90
16th to endDay
27%11%37%13%10%
96
January1st to 15thNight
18%9%32%30%8%
720
16th to endNight
19%8%38%30%3
768
February1st to 15thNight
19%8%39%30%2
704
16th to endNight
15%10%41%28%3
631
March1st to 15thNight
15%8%36%31%7%
720
16th to endNight
17%7%30%32%10%
768
April1st to 15thNight
13%10%31%32%12%
718
16th to endNight
15%6%26%32%18%
658
May1st to 15thNight
13%425%36%18%1
540
16th to endNight
11%215%34%34%2
563
June1st to 15thNight
10%211%38%30%6%
540
16th to endNight
6%111%34%38%7%
540
July1st to 15thNight
8%7%37%40%5%
510
16th to endNight
6%7%28%46%9%
564
August1st to 15thNight
10%16%28%46%6%
539
16th to endNight
11%6%27%46%8%
679
September1st to 15thNight
11%26%31%41%7%
720
16th to endNight
21%212%28%30%3
681
October1st to 15thNight
20%118%28%25%4
660
16th to endNight
12%5%24%30%22%3
704
November1st to 15thNight
14%426%33%18%3
700
16th to endNight
14%7%25%34%15%1
720
December1st to 15thNight
17%7%25%38%10%
720
16th to endNight
23%7%26%32%9%
768
Page generated at 2017-09-22 07:35:29. Version ac04

Copyright 2017 A. Danko


Indian Trail Clear Sky Chart | Charts Home