High Cliff State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the High Cliff State Park 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
36%
16090
16%
46881
9%
16048
42%
16048
23%
31722

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
24%
900
13%
2506
5%
895
31%
895
16%
1872
January16th to endNight
19%
960
12%
2688
3%
960
27%
960
16%
2041
February1st to 15thNight
24%
841
15%
2263
3%
841
31%
841
19%
1624
February16th to endNight
29%
631
16%
1893
6%
631
37%
631
17%
1358
March1st to 15thNight
33%
720
15%
2160
8%
720
38%
720
21%
1448
March16th to endNight
35%
618
18%
2012
14%
618
42%
618
19%
1371
April1st to 15thNight
28%
539
16%
1797
11%
539
37%
539
18%
1239
April16th to endNight
35%
540
18%
1707
11%
540
42%
540
22%
1144
May1st to 15thNight
29%
540
15%
1524
7%
540
37%
540
23%
1048
May16th to endNight
43%
562
15%
1498
7%
561
49%
561
31%
974
June1st to 15thNight
48%
540
13%
1440
6%
540
52%
540
30%
940
June16th to endNight
51%
540
13%
1440
7%
540
54%
540
33%
915
July1st to 15thNight
63%
510
17%
1360
10%
510
66%
510
43%
796
July16th to endNight
59%
564
19%
1417
11%
531
64%
531
42%
839
August1st to 15thNight
67%
539
23%
1479
18%
536
70%
536
41%
864
August16th to endNight
60%
573
21%
1910
20%
573
65%
573
34%
1088
September1st to 15thNight
57%
540
25%
1800
24%
540
63%
540
33%
1012
September16th to endNight
52%
675
21%
1875
14%
675
58%
675
33%
1150
October1st to 15thNight
42%
660
21%
1919
14%
660
48%
660
29%
1211
October16th to endNight
30%
704
14%
2255
7%
704
39%
704
19%
1536
November1st to 15thNight
32%
700
21%
2276
14%
700
41%
700
23%
1450
November16th to endNight
25%
834
14%
2454
6%
834
33%
834
17%
1780
December1st to 15thNight
17%
900
9%
2520
1%
900
24%
900
14%
1913
December16th to endNight
18%
960
11%
2688
2%
960
26%
960
13%
2109

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%7%36%5%35%45%7%37%
47985
Night
13%8%36%5%34446%39%
47049
Cloud CoverDay
13%8%36%5%35%45%7%36%
47994
Night
13%8%36%5%34446%39%
47054
TransparencyDay
45%6%13%22%10%1
47671
Night
45%5%13%22%12%1
46881
SeeingDay
16%7%28%27%14%5%
6085
Night
17%7%31%30%11%1
16094

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%5%8%7%35%45%5%28%
1432
16th to endDay
13%12%6%12%7%345%45%23%
1536
February1st to 15thDay
12%12%49%5%35%5%5%5%32%
1596
16th to endDay
13%10%48%5%36%336%34%
1580
March1st to 15thDay
14%8%46%5%3446%7%35%
1790
16th to endDay
16%8%35%5%25%45%7%34%
2221
April1st to 15thDay
16%10%46%5%25%5%46%31%
2151
16th to endDay
19%8%26%5%33445%35%
2251
May1st to 15thDay
17%6%35%6%45%5%5%7%33%
2424
16th to endDay
10%423436%5%6%9%41%
2617
June1st to 15thDay
13%6%25%5%2446%7%40%
2520
16th to endDay
8%5%25%435%5%6%10%41%
2520
July1st to 15thDay
7%314425%5%7%10%47%
2520
16th to endDay
8%424435%5%6%8%46%
2655
August1st to 15thDay
7%4145%45%5%7%10%43%
2469
16th to endDay
12%5%145%2445%7%45%
2292
September1st to 15thDay
12%324434448%47%
2154
16th to endDay
10%6%35%5%345%5%8%40%
1872
October1st to 15thDay
17%7%24424346%41%
1708
16th to endDay
16%9%36%6%345%5%7%32%
1615
November1st to 15thDay
13%8%37%435%5%5%5%36%
1582
16th to endDay
14%11%5%8%6%3445%6%28%
1504
December1st to 15thDay
15%11%5%9%7%46%45%5%24%
1440
16th to endDay
19%13%5%10%8%35%445%19%
1536
January1st to 15thNight
14%12%5%7%6%3443432%
2506
16th to endNight
12%12%5%10%7%35%445%27%
2688
February1st to 15thNight
11%12%5%7%5%34445%36%
2261
16th to endNight
14%10%5%7%6%3434434%
1893
March1st to 15thNight
14%7%35%4345%45%39%
2147
16th to endNight
16%6%46%5%35%446%36%
2012
April1st to 15thNight
20%8%45%5%2435%5%35%
1797
16th to endNight
18%7%35%42435%6%38%
1707
May1st to 15thNight
19%6%245%3445%6%37%
1524
16th to endNight
10%5%344346%7%8%41%
1496
June1st to 15thNight
10%5%25%5%345%5%7%44%
1440
16th to endNight
9%4234245%6%9%45%
1440
July1st to 15thNight
6%31442347%7%53%
1440
16th to endNight
6%314335%5%5%8%52%
1513
August1st to 15thNight
7%3143245%6%9%51%
1488
16th to endNight
10%425%42445%7%50%
1910
September1st to 15thNight
11%314423346%54%
1800
16th to endNight
11%42442435%7%48%
1875
October1st to 15thNight
15%5%24323436%46%
1919
16th to endNight
17%7%35%5%34447%35%
2255
November1st to 15thNight
14%6%35%424446%43%
2276
16th to endNight
16%10%36%6%25%445%31%
2454
December1st to 15thNight
16%13%47%5%35%447%26%
2520
16th to endNight
19%14%5%7%6%34345%25%
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
12%13%49%7%35%45%5%28%
1432
16th to endDay
12%13%6%12%7%345%5%5%22%
1536
February1st to 15thDay
11%12%48%6%25%45%5%31%
1596
16th to endDay
13%10%47%6%35%346%33%
1580
March1st to 15thDay
14%9%46%5%3445%8%34%
1800
16th to endDay
16%9%45%5%3445%7%33%
2220
April1st to 15thDay
16%11%45%5%35%446%30%
2151
16th to endDay
20%8%35%5%2335%5%35%
2251
May1st to 15thDay
17%7%26%5%35%5%46%33%
2424
16th to endDay
11%4245%36%6%6%9%41%
2617
June1st to 15thDay
13%6%25%5%345%5%9%39%
2520
16th to endDay
8%5%25%435%6%6%10%41%
2520
July1st to 15thDay
7%314435%5%8%9%46%
2520
16th to endDay
8%425%425%5%6%8%45%
2655
August1st to 15thDay
7%425%5%36%6%6%10%42%
2469
16th to endDay
13%5%135%25%45%7%44%
2292
September1st to 15thDay
12%415%424448%47%
2154
16th to endDay
9%7%35%5%35%46%8%40%
1872
October1st to 15thDay
17%6%25%42335%6%41%
1708
16th to endDay
17%9%36%5%345%47%32%
1615
November1st to 15thDay
13%9%36%5%36%45%6%36%
1582
16th to endDay
14%11%5%8%5%34446%29%
1504
December1st to 15thDay
14%11%5%8%8%36%5%5%5%25%
1440
16th to endDay
19%12%6%10%7%36%445%19%
1536
January1st to 15thNight
14%13%5%8%6%25%43432%
2506
16th to endNight
12%11%6%10%6%45%5%45%27%
2688
February1st to 15thNight
11%12%5%7%5%24445%36%
2254
16th to endNight
14%10%5%7%5%4444435%
1893
March1st to 15thNight
15%7%35%5%3445%5%39%
2160
16th to endNight
16%6%46%5%35%45%6%36%
2012
April1st to 15thNight
20%7%46%5%24345%35%
1797
16th to endNight
18%7%25%42435%6%38%
1707
May1st to 15thNight
19%6%25%5%245%5%6%36%
1523
16th to endNight
10%5%25%435%5%7%9%41%
1496
June1st to 15thNight
9%5%245%25%5%5%7%44%
1440
16th to endNight
10%3244345%7%8%45%
1440
July1st to 15thNight
7%31333346%8%54%
1440
16th to endNight
5%215%3245%5%8%53%
1513
August1st to 15thNight
7%3233245%5%10%50%
1488
16th to endNight
10%5%2442435%7%50%
1910
September1st to 15thNight
10%413423337%54%
1800
16th to endNight
11%5%2433435%8%47%
1875
October1st to 15thNight
14%5%24423347%46%
1919
16th to endNight
16%8%35%5%3445%7%36%
2255
November1st to 15thNight
14%7%35%423446%43%
2276
16th to endNight
16%10%45%7%34446%32%
2454
December1st to 15thNight
16%12%48%5%35%446%28%
2520
16th to endNight
19%14%5%7%6%34345%25%
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
56%6%11%19%6%
1433
16th to endDay
61%5%12%13%6%
1536
February1st to 15thDay
52%411%21%8%
1598
16th to endDay
51%5%10%20%9%1
1580
March1st to 15thDay
48%7%14%19%9%1
1800
16th to endDay
49%6%16%20%6%1
2221
April1st to 15thDay
53%6%10%19%9%
2151
16th to endDay
49%5%12%19%11%2
2251
May1st to 15thDay
49%6%13%21%8%
2424
16th to endDay
37%7%13%24%13%1
2621
June1st to 15thDay
40%7%13%27%10%
2520
16th to endDay
35%9%15%24%14%
2520
July1st to 15thDay
29%9%13%29%14%2
2371
16th to endDay
33%9%14%24%15%3
2488
August1st to 15thDay
33%9%16%29%10%1
2454
16th to endDay
38%6%14%25%13%1
2292
September1st to 15thDay
35%5%12%31%14%
2154
16th to endDay
40%7%15%28%8%
1872
October1st to 15thDay
44%413%25%11%
1708
16th to endDay
50%7%12%21%6%
1615
November1st to 15thDay
48%5%11%22%10%1
1582
16th to endDay
55%5%16%17%4
1504
December1st to 15thDay
60%5%13%15%5%
1440
16th to endDay
67%410%12%4
1536
January1st to 15thNight
55%49%18%10%
2506
16th to endNight
57%5%12%18%6%
2688
February1st to 15thNight
50%410%23%9%1
2263
16th to endNight
52%412%19%9%
1893
March1st to 15thNight
45%6%14%20%12%1
2160
16th to endNight
48%5%11%24%9%
2012
April1st to 15thNight
51%47%20%14%2
1797
16th to endNight
46%411%20%14%2
1707
May1st to 15thNight
46%5%14%21%12%
1524
16th to endNight
36%7%15%23%15%1
1498
June1st to 15thNight
37%7%11%28%14%
1440
16th to endNight
32%9%15%25%15%2
1440
July1st to 15thNight
26%5%13%30%19%3
1360
16th to endNight
26%7%15%30%16%3
1417
August1st to 15thNight
27%6%15%34%14%1
1479
16th to endNight
32%415%26%18%2
1910
September1st to 15thNight
31%5%9%28%23%1
1800
16th to endNight
35%413%33%11%1
1875
October1st to 15thNight
38%5%12%27%14%1
1919
16th to endNight
46%6%15%19%11%
2255
November1st to 15thNight
42%413%23%14%2
2276
16th to endNight
53%5%16%18%6%
2454
December1st to 15thNight
57%5%14%16%6%
2520
16th to endNight
61%5%12%14%5%
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
23%7%40%24%4
90
16th to endDay
19%7%29%33%10%
96
February1st to 15thDay
16%14%42%18%7%
90
16th to endDay
20%12%38%18%8%1
81
March1st to 15thDay
26%14%31%16%8%2
90
16th to endDay
29%5%27%22%12%2
237
April1st to 15thDay
27%9%27%26%9%
270
16th to endDay
24%9%28%23%10%3
270
May1st to 15thDay
20%10%33%24%8%2
381
16th to endDay
15%10%32%24%11%4
517
June1st to 15thDay
16%6%32%28%14%2
495
16th to endDay
11%8%32%30%12%4
495
July1st to 15thDay
10%6%23%30%21%8%
475
16th to endDay
9%428%30%18%8%
515
August1st to 15thDay
10%220%32%25%8%
451
16th to endDay
18%415%28%21%11%
332
September1st to 15thDay
16%319%27%19%13%
315
16th to endDay
12%6%19%36%20%4
275
October1st to 15thDay
16%10%21%29%18%4
148
16th to endDay
17%11%41%21%7%
96
November1st to 15thDay
5%15%30%33%13%2
90
16th to endDay
30%15%36%8%8%
90
December1st to 15thDay
18%18%48%11%2
90
16th to endDay
29%23%39%6%1
96
January1st to 15thNight
19%12%34%26%6%
900
16th to endNight
18%7%42%25%5%
960
February1st to 15thNight
17%11%36%26%6%
844
16th to endNight
19%10%31%29%7%
631
March1st to 15thNight
19%8%32%30%8%1
720
16th to endNight
17%6%30%32%10%1
618
April1st to 15thNight
23%6%36%26%6%
539
16th to endNight
21%6%33%30%8%
540
May1st to 15thNight
22%7%35%25%7%
540
16th to endNight
12%5%32%35%13%
563
June1st to 15thNight
11%5%27%40%15%
540
16th to endNight
11%329%40%14%1
540
July1st to 15thNight
8%219%46%21%1
510
16th to endNight
6%124%41%24%1
564
August1st to 15thNight
8%115%47%24%2
539
16th to endNight
11%219%38%24%3
573
September1st to 15thNight
13%221%32%22%7%
540
16th to endNight
14%6%21%32%22%2
675
October1st to 15thNight
16%8%28%28%16%1
660
16th to endNight
22%8%31%26%9%
704
November1st to 15thNight
18%9%37%25%8%1
700
16th to endNight
21%13%32%24%7%
834
December1st to 15thNight
25%13%37%19%4
900
16th to endNight
24%11%36%23%31
960
Page generated at 2017-09-22 06:35:33. Version ac04

Copyright 2017 A. Danko


High Cliff State Park Clear Sky Chart | Charts Home