Elk Forest
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Elk Forest clear sky chart from 2005-11-05 to 2017-09-23.

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
32%
15183
20%
46933
10%
15146
44%
15146
21%
29796

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
21%
719
21%
2494
9%
716
37%
716
16%
1560
January16th to endNight
17%
768
22%
2496
6%
768
37%
768
19%
1572
February1st to 15thNight
15%
704
18%
2273
5%
701
31%
701
16%
1438
February16th to endNight
16%
631
25%
1893
6%
631
38%
631
19%
1195
March1st to 15thNight
21%
720
20%
2067
7%
720
36%
720
22%
1319
March16th to endNight
22%
768
21%
2046
8%
768
33%
768
24%
1369
April1st to 15thNight
23%
718
18%
1796
4%
718
31%
718
24%
1197
April16th to endNight
30%
720
18%
1800
5%
720
38%
720
24%
1210
May1st to 15thNight
27%
534
16%
1614
7%
534
35%
534
17%
1104
May16th to endNight
41%
374
16%
1497
12%
374
50%
374
16%
922
June1st to 15thNight
46%
360
17%
1440
16%
360
54%
360
20%
859
June16th to endNight
48%
360
16%
1440
15%
360
56%
360
22%
840
July1st to 15thNight
50%
340
12%
1360
13%
340
53%
340
16%
869
July16th to endNight
55%
453
15%
1489
13%
425
62%
425
25%
890
August1st to 15thNight
56%
569
17%
1639
10%
566
59%
566
27%
1047
August16th to endNight
59%
764
18%
1910
10%
764
61%
764
32%
1248
September1st to 15thNight
52%
720
24%
1800
14%
720
56%
720
32%
1188
September16th to endNight
49%
689
25%
1867
16%
689
55%
689
28%
1208
October1st to 15thNight
41%
660
22%
1980
17%
660
49%
660
25%
1251
October16th to endNight
33%
704
26%
2120
13%
704
50%
704
28%
1267
November1st to 15thNight
28%
700
23%
2277
12%
700
43%
700
23%
1390
November16th to endNight
26%
720
21%
2427
9%
720
41%
720
18%
1511
December1st to 15thNight
20%
720
17%
2520
6%
720
35%
720
14%
1636
December16th to endNight
17%
768
21%
2688
6%
768
36%
768
14%
1706

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%244345%5%7%42%
47966
Night
14%5%2442445%7%43%
47110
Cloud CoverDay
13%5%244345%5%7%42%
47976
Night
14%5%2442445%7%43%
47115
TransparencyDay
39%6%12%22%15%2
47661
Night
39%5%11%22%16%2
46933
SeeingDay
16%15%23%23%15%6%
5756
Night
15%21%24%25%11%1
15185

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
15%6%24424447%42%
1441
16th to endDay
14%6%245%24446%43%
1728
February1st to 15thDay
15%6%244345%5%5%42%
1588
16th to endDay
13%7%35%435%46%5%40%
1580
March1st to 15thDay
14%5%35%32445%7%43%
1879
16th to endDay
17%5%24434445%42%
2176
April1st to 15thDay
15%6%23434447%44%
2152
16th to endDay
15%42442445%7%44%
2160
May1st to 15thDay
16%5%25%5%35%5%6%7%37%
2345
16th to endDay
13%5%23435%5%5%9%39%
2618
June1st to 15thDay
11%4245%36%5%7%10%37%
2520
16th to endDay
10%3244345%5%10%43%
2520
July1st to 15thDay
8%425%5%45%6%7%9%41%
2520
16th to endDay
5%3246%46%6%8%12%39%
2574
August1st to 15thDay
10%425%6%346%6%10%39%
2296
16th to endDay
9%5%245%245%7%9%43%
2292
September1st to 15thDay
12%42444345%7%46%
2160
16th to endDay
14%5%25%5%3445%7%40%
1928
October1st to 15thDay
15%5%13423446%46%
1650
16th to endDay
16%5%14434345%47%
1752
November1st to 15thDay
15%6%23424437%46%
1581
16th to endDay
16%5%34423345%46%
1530
December1st to 15thDay
16%5%2443445%7%41%
1440
16th to endDay
17%7%2442445%6%38%
1536
January1st to 15thNight
17%5%24424446%41%
2494
16th to endNight
16%6%24423346%44%
2496
February1st to 15thNight
14%6%25%424447%41%
2271
16th to endNight
15%6%23334445%46%
1893
March1st to 15thNight
16%433424447%44%
2055
16th to endNight
16%5%25%5%23346%43%
2046
April1st to 15thNight
15%5%25%424447%43%
1796
16th to endNight
18%5%2332335%6%43%
1800
May1st to 15thNight
17%6%36%42335%7%38%
1614
16th to endNight
14%6%245%3446%8%40%
1495
June1st to 15thNight
12%5%344245%5%7%44%
1440
16th to endNight
9%5%25%426%5%5%9%43%
1440
July1st to 15thNight
8%425%7%37%6%7%8%36%
1440
16th to endNight
6%325%6%346%7%11%42%
1591
August1st to 15thNight
8%5%245%35%47%9%43%
1650
16th to endNight
11%425%4245%5%8%46%
1910
September1st to 15thNight
12%6%25%32445%7%47%
1800
16th to endNight
12%6%2442435%8%44%
1867
October1st to 15thNight
16%5%245%2345%6%44%
1980
16th to endNight
15%413423436%51%
2120
November1st to 15thNight
14%6%34323335%49%
2277
16th to endNight
16%5%145%2446%6%42%
2427
December1st to 15thNight
18%5%25%5%2445%6%38%
2520
16th to endNight
17%5%2442445%7%40%
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
15%6%25%424446%42%
1441
16th to endDay
14%7%235%3445%6%43%
1728
February1st to 15thDay
15%6%244245%45%42%
1588
16th to endDay
13%7%35%4245%5%6%41%
1580
March1st to 15thDay
14%5%25%32445%7%43%
1890
16th to endDay
17%5%24435%445%42%
2175
April1st to 15thDay
15%5%24424447%44%
2152
16th to endDay
15%42442445%6%44%
2160
May1st to 15thDay
16%5%25%5%25%5%6%6%38%
2345
16th to endDay
13%423436%5%5%9%40%
2618
June1st to 15thDay
11%4245%36%6%6%11%37%
2520
16th to endDay
10%314435%5%6%10%43%
2520
July1st to 15thDay
8%425%6%35%6%7%9%42%
2520
16th to endDay
5%3246%46%6%8%12%40%
2574
August1st to 15thDay
10%425%5%346%6%9%40%
2296
16th to endDay
9%5%245%245%7%9%43%
2292
September1st to 15thDay
13%4245%34447%46%
2160
16th to endDay
14%5%25%5%3445%7%40%
1928
October1st to 15thDay
16%6%233235%46%46%
1650
16th to endDay
16%424423445%47%
1752
November1st to 15thDay
15%6%23323436%46%
1581
16th to endDay
16%5%24424345%46%
1530
December1st to 15thDay
16%5%25%33345%7%41%
1440
16th to endDay
17%7%24425%45%6%39%
1536
January1st to 15thNight
17%5%2442435%6%41%
2494
16th to endNight
16%6%24424346%43%
2496
February1st to 15thNight
14%6%25%42445%7%41%
2264
16th to endNight
15%6%23424445%47%
1893
March1st to 15thNight
16%423424447%44%
2067
16th to endNight
16%5%25%5%23445%43%
2046
April1st to 15thNight
15%5%24424446%43%
1796
16th to endNight
18%5%2332345%6%44%
1800
May1st to 15thNight
17%7%35%42435%7%38%
1614
16th to endNight
14%6%245%25%45%8%40%
1495
June1st to 15thNight
12%5%344245%5%7%44%
1440
16th to endNight
8%435%426%5%5%10%43%
1440
July1st to 15thNight
8%5%26%7%36%6%8%8%36%
1440
16th to endNight
6%325%5%45%5%8%10%42%
1591
August1st to 15thNight
8%5%15%5%35%47%9%43%
1650
16th to endNight
10%5%15%43445%8%45%
1910
September1st to 15thNight
12%5%243335%47%46%
1800
16th to endNight
13%6%2442435%8%44%
1867
October1st to 15thNight
16%5%2442245%6%44%
1980
16th to endNight
16%413323336%51%
2120
November1st to 15thNight
14%5%34313335%49%
2277
16th to endNight
16%5%145%3446%6%42%
2427
December1st to 15thNight
18%5%35%5%2445%6%38%
2520
16th to endNight
17%5%24434447%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
42%5%13%20%13%4
1442
16th to endDay
41%5%11%24%14%3
1728
February1st to 15thDay
42%5%11%25%12%2
1590
16th to endDay
42%5%12%26%12%2
1580
March1st to 15thDay
41%5%12%24%15%1
1890
16th to endDay
43%5%9%20%18%3
2176
April1st to 15thDay
40%5%11%22%15%4
2152
16th to endDay
39%5%10%17%21%5%
2160
May1st to 15thDay
43%7%12%19%15%2
2345
16th to endDay
38%9%14%21%13%1
2622
June1st to 15thDay
38%9%14%24%11%1
2520
16th to endDay
34%8%16%21%17%1
2520
July1st to 15thDay
37%7%14%21%15%3
2371
16th to endDay
33%10%15%25%13%2
2413
August1st to 15thDay
37%8%14%21%16%1
2283
16th to endDay
35%7%13%21%17%3
2292
September1st to 15thDay
36%6%11%22%20%2
2160
16th to endDay
41%5%9%18%22%2
1928
October1st to 15thDay
38%5%13%23%18%2
1650
16th to endDay
38%49%26%18%1
1752
November1st to 15thDay
39%412%21%18%3
1581
16th to endDay
39%410%27%15%2
1530
December1st to 15thDay
40%7%14%23%11%1
1440
16th to endDay
44%6%14%21%12%1
1536
January1st to 15thNight
42%5%12%20%16%3
2494
16th to endNight
41%411%25%15%1
2496
February1st to 15thNight
42%412%23%14%2
2273
16th to endNight
39%49%22%19%3
1893
March1st to 15thNight
39%413%24%15%2
2067
16th to endNight
42%411%20%17%3
2046
April1st to 15thNight
40%412%20%18%4
1796
16th to endNight
39%6%10%18%19%5%
1800
May1st to 15thNight
46%6%10%16%17%2
1614
16th to endNight
41%7%14%16%16%2
1497
June1st to 15thNight
38%6%13%23%17%
1440
16th to endNight
34%8%13%24%16%2
1440
July1st to 15thNight
42%9%15%17%12%3
1360
16th to endNight
33%10%17%22%14%1
1489
August1st to 15thNight
35%9%13%21%19%1
1639
16th to endNight
34%8%13%21%19%2
1910
September1st to 15thNight
36%7%9%22%21%3
1800
16th to endNight
38%47%21%23%3
1867
October1st to 15thNight
39%5%11%23%17%2
1980
16th to endNight
35%49%29%19%2
2120
November1st to 15thNight
39%49%21%17%7%
2277
16th to endNight
40%5%11%23%16%2
2427
December1st to 15thNight
45%5%11%22%13%1
2520
16th to endNight
42%6%13%23%12%1
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
22%21%42%9%11
61
16th to endDay
22%23%35%16%1
96
February1st to 15thDay
21%28%30%17%1
104
16th to endDay
15%26%37%18%1
239
March1st to 15thDay
16%27%27%21%7%
270
16th to endDay
19%21%34%15%5%2
288
April1st to 15thDay
18%23%29%17%7%3
270
16th to endDay
20%18%23%22%11%3
270
May1st to 15thDay
27%22%23%13%11%1
288
16th to endDay
18%13%17%25%19%5%
331
June1st to 15thDay
13%12%24%23%18%6%
315
16th to endDay
10%13%25%29%16%4
315
July1st to 15thDay
12%7%17%30%23%8%
305
16th to endDay
6%10%11%31%29%9%
326
August1st to 15thDay
14%7%14%29%22%12%
313
16th to endDay
9%5%10%32%24%17%
332
September1st to 15thDay
12%9%21%21%20%15%
315
16th to endDay
20%7%13%28%18%12%
283
October1st to 15thDay
20%8%19%29%14%7%
255
16th to endDay
14%16%30%24%13%1
271
November1st to 15thDay
15%18%28%17%18%1
235
16th to endDay
16%23%32%17%11%
150
December1st to 15thDay
20%20%33%11%13%1
60
16th to endDay
37%10%32%17%1
64
January1st to 15thNight
16%29%29%19%4
720
16th to endNight
18%27%33%19%
768
February1st to 15thNight
15%29%35%17%1
704
16th to endNight
17%31%32%17%1
631
March1st to 15thNight
18%27%29%19%4
720
16th to endNight
18%23%33%17%6%
768
April1st to 15thNight
16%26%29%22%4
718
16th to endNight
16%22%26%24%10%
720
May1st to 15thNight
19%21%26%25%6%
534
16th to endNight
13%20%17%30%16%
375
June1st to 15thNight
13%17%16%35%16%
360
16th to endNight
5%17%19%41%15%
360
July1st to 15thNight
10%13%16%38%20%
340
16th to endNight
8%17%12%33%26%2
453
August1st to 15thNight
11%10%12%37%26%2
569
16th to endNight
12%9%12%34%28%3
764
September1st to 15thNight
13%10%16%32%23%2
720
16th to endNight
16%10%14%30%23%4
689
October1st to 15thNight
20%13%19%28%15%2
660
16th to endNight
17%17%29%25%10%
704
November1st to 15thNight
14%22%28%20%11%1
700
16th to endNight
15%27%27%22%7%
720
December1st to 15thNight
19%26%27%17%8%
720
16th to endNight
17%29%29%19%2
768
Page generated at 2017-09-24 09:15:48. Version ac04

Copyright 2017 A. Danko


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