This page made possible by the sponsorship of:
.

Kline-Dodge Dark Sky Site
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Kline-Dodge Dark Sky Site clear sky chart from 2005-11-06 to 2024-01-16.

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
48%
24572
27%
74439
16%
24522
57%
24522
38%
41177

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 10thNight
47%
949
30%
2647
18%
946
59%
946
44%
1454
January11th to 20thNight
47%
926
30%
2591
18%
926
57%
926
41%
1453
January21st to endNight
43%
831
30%
2613
19%
831
56%
831
37%
1424
February1st to 10thNight
37%
720
26%
2286
14%
720
51%
720
38%
1240
February11th to 20thNight
38%
701
25%
2098
14%
700
49%
700
33%
1240
February21st to endNight
40%
592
35%
1776
15%
592
57%
592
41%
954
March1st to 10thNight
41%
720
26%
2160
13%
720
52%
720
38%
1189
March11th to 20thNight
40%
720
26%
2084
14%
720
48%
720
38%
1207
March21st to endNight
36%
608
26%
1994
13%
608
53%
608
31%
1134
April1st to 10thNight
31%
540
22%
1800
12%
540
47%
540
30%
1014
April11th to 20thNight
33%
533
20%
1777
11%
533
48%
533
26%
1053
April21st to endNight
38%
540
20%
1800
16%
540
47%
540
27%
1089
May1st to 10thNight
41%
540
20%
1620
14%
540
49%
540
27%
1028
May11th to 20thNight
43%
531
15%
1515
13%
531
47%
531
29%
975
May21st to endNight
42%
583
15%
1552
8%
582
48%
582
33%
963
June1st to 10thNight
56%
540
20%
1440
12%
540
61%
540
44%
815
June11th to 20thNight
46%
540
22%
1440
11%
540
54%
540
45%
806
June21st to endNight
60%
540
23%
1440
17%
540
64%
540
41%
840
July1st to 10thNight
55%
525
17%
1400
11%
525
59%
525
35%
877
July11th to 20thNight
65%
522
26%
1392
17%
522
71%
522
42%
803
July21st to endNight
68%
591
21%
1488
16%
558
70%
558
35%
933
August1st to 10thNight
64%
537
15%
1625
13%
534
66%
534
29%
1005
August11th to 20thNight
58%
534
24%
1778
23%
534
66%
534
37%
947
August21st to endNight
61%
594
26%
1980
26%
594
68%
594
41%
1000
September1st to 10thNight
61%
540
30%
1800
25%
540
71%
540
43%
900
September11th to 20thNight
59%
540
32%
1870
26%
540
70%
540
43%
890
September21st to endNight
58%
540
33%
1980
29%
540
68%
540
43%
921
October1st to 10thNight
47%
616
31%
2056
20%
616
58%
616
37%
1077
October11th to 20thNight
56%
720
35%
2160
19%
720
66%
720
51%
1053
October21st to endNight
52%
901
33%
2485
17%
901
60%
901
46%
1347
November1st to 10thNight
52%
925
34%
2405
16%
925
61%
925
55%
1252
November11th to 20thNight
46%
950
36%
2470
17%
950
56%
950
52%
1330
November21st to endNight
52%
950
31%
2474
18%
950
60%
950
45%
1411
December1st to 10thNight
44%
950
28%
2660
14%
950
55%
950
43%
1466
December11th to 20thNight
44%
948
31%
3085
17%
948
54%
948
37%
1603
December21st to endNight
40%
1035
19%
4698
15%
1026
51%
1026
25%
2484

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
5%5%2442446%8%56%
74827
Night
6%5%2443445%8%54%
74983
TransparencyDay
26%5%11%25%24%10%
74531
Night
27%6%11%24%23%8%
74801
SeeingDay
8%8%25%32%20%7%
14454
Night
8%5%33%41%12%1
24589

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 10thDay
25%24413347%63%
1518
11th to 20thDay
5%6%3442446%6%57%
1480
21st to endDay
28%345%23447%57%
1760
February1st to 10thDay
38%37%434446%56%
1672
11th to 20thDay
26%25%445%5%5%7%56%
1749
21st to endDay
37%35%5%34446%56%
1480
March1st to 10thDay
45%25%425%45%8%56%
1800
11th to 20thDay
5%6%34424346%58%
1873
21st to endDay
7%8%35%3245%6%8%49%
2362
April1st to 10thDay
7%6%24425%45%7%54%
2160
11th to 20thDay
10%7%35%4345%5%8%47%
2131
21st to endDay
10%7%244345%7%7%49%
2160
May1st to 10thDay
9%7%25%5%35%5%6%8%45%
2338
11th to 20thDay
10%6%245%35%47%10%44%
2378
21st to endDay
8%4245%346%7%9%50%
2724
June1st to 10thDay
6%313425%5%7%9%54%
2520
11th to 20thDay
6%323435%5%6%9%56%
2520
21st to endDay
3314435%5%8%9%56%
2520
July1st to 10thDay
6%214435%6%7%10%53%
2520
11th to 20thDay
2213435%5%7%10%57%
2520
21st to endDay
5%3245%35%7%8%10%49%
2742
August1st to 10thDay
42145%36%7%8%11%49%
2298
11th to 20thDay
5%21222347%11%61%
2123
21st to endDay
3313435%5%6%9%59%
2376
September1st to 10thDay
5%213424347%65%
2160
11th to 20thDay
5%21331346%7%64%
2088
21st to endDay
6%313322346%67%
1980
October1st to 10thDay
8%413323346%63%
1900
11th to 20thDay
5%312322346%69%
1800
21st to endDay
6%6%23322345%63%
1851
November1st to 10thDay
2424313347%68%
1673
11th to 20thDay
35%145%2335%7%62%
1710
21st to endDay
36%34323345%63%
1701
December1st to 10thDay
27%2443445%7%58%
1520
11th to 20thDay
36%25%435%5%5%7%56%
1926
21st to endDay
6%9%36%5%2435%6%50%
2794
January1st to 10thNight
36%35%42445%6%58%
2647
11th to 20thNight
46%24435%5%5%6%57%
2591
21st to endNight
36%36%5%34446%55%
2613
February1st to 10thNight
38%35%424447%55%
2286
11th to 20thNight
37%47%6%35%6%5%8%48%
2098
21st to endNight
38%26%33345%6%57%
1776
March1st to 10thNight
5%6%3443445%7%56%
2160
11th to 20thNight
7%7%24434447%54%
2084
21st to endNight
6%8%345%2445%8%51%
1994
April1st to 10thNight
8%8%344345%5%6%51%
1800
11th to 20thNight
11%7%345%35%45%8%45%
1777
21st to endNight
13%7%25%5%345%5%7%45%
1800
May1st to 10thNight
12%5%35%5%35%5%6%7%44%
1620
11th to 20thNight
13%6%25%43445%8%46%
1514
21st to endNight
11%4145%335%6%9%48%
1552
June1st to 10thNight
5%3133246%7%12%54%
1440
11th to 20thNight
7%32333447%8%58%
1440
21st to endNight
44235%36%5%8%11%48%
1440
July1st to 10thNight
7%4145%36%6%8%10%46%
1440
11th to 20thNight
22145%46%6%7%10%52%
1440
21st to endNight
5%4245%37%7%7%11%45%
1576
August1st to 10thNight
5%435%7%46%6%8%10%43%
1633
11th to 20thNight
6%3244346%7%10%51%
1778
21st to endNight
4324425%5%7%8%56%
1980
September1st to 10thNight
6%4133345%6%8%57%
1800
11th to 20thNight
7%3134235%7%7%59%
1870
21st to endNight
5%324324347%64%
1980
October1st to 10thNight
11%5%23323346%58%
2056
11th to 20thNight
441332235%6%68%
2160
21st to endNight
7%6%23323346%63%
2485
November1st to 10thNight
242432335%8%64%
2405
11th to 20thNight
35%2432335%7%63%
2470
21st to endNight
5%6%2442345%7%58%
2474
December1st to 10thNight
26%36%42435%7%58%
2660
11th to 20thNight
36%3442445%8%56%
3271
21st to endNight
7%9%35%42445%6%50%
4873

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 10thDay
21%412%31%25%7%
1519
11th to 20thDay
27%5%9%27%26%7%
1480
21st to endDay
27%39%30%23%7%
1760
February1st to 10thDay
30%411%28%19%7%
1672
11th to 20thDay
28%5%9%28%24%7%
1759
21st to endDay
29%410%24%24%10%
1480
March1st to 10thDay
26%5%11%23%26%9%
1800
11th to 20thDay
28%310%23%29%7%
1873
21st to endDay
32%5%15%23%19%6%
2362
April1st to 10thDay
28%5%13%23%22%9%
2160
11th to 20thDay
35%5%12%23%18%8%
2134
21st to endDay
32%6%12%27%21%3
2160
May1st to 10thDay
36%8%12%25%17%3
2338
11th to 20thDay
34%8%15%27%15%2
2382
21st to endDay
28%8%16%26%16%6%
2724
June1st to 10thDay
24%8%16%25%17%9%
2520
11th to 20thDay
25%6%11%20%24%15%
2520
21st to endDay
21%6%11%24%26%12%
2520
July1st to 10thDay
26%8%11%21%23%11%
2451
11th to 20thDay
20%6%12%24%27%10%
2445
21st to endDay
26%9%15%28%16%6%
2590
August1st to 10thDay
25%9%18%25%15%7%
2282
11th to 20thDay
18%6%11%27%26%13%
2123
21st to endDay
21%6%9%21%30%13%
2376
September1st to 10thDay
21%47%23%27%18%
2160
11th to 20thDay
18%5%8%19%31%18%
2088
21st to endDay
20%37%22%35%13%
1980
October1st to 10thDay
24%39%22%29%14%
1900
11th to 20thDay
17%47%24%32%16%
1800
21st to endDay
24%38%26%24%15%
1851
November1st to 10thDay
17%38%29%26%16%
1673
11th to 20thDay
22%36%26%33%9%
1710
21st to endDay
24%37%21%30%15%
1701
December1st to 10thDay
26%5%9%29%24%7%
1520
11th to 20thDay
27%5%10%23%31%5%
1924
21st to endDay
35%48%25%21%6%
2794
January1st to 10thNight
26%410%28%28%6%
2647
11th to 20thNight
26%6%8%25%27%9%
2591
21st to endNight
29%49%29%22%7%
2613
February1st to 10thNight
29%412%26%22%7%
2286
11th to 20thNight
33%6%10%26%19%6%
2098
21st to endNight
27%49%24%26%11%
1776
March1st to 10thNight
28%5%10%23%26%9%
2160
11th to 20thNight
30%5%11%21%27%6%
2084
21st to endNight
31%6%11%25%22%4
1994
April1st to 10thNight
32%5%12%22%21%8%
1800
11th to 20thNight
37%5%13%21%17%6%
1777
21st to endNight
36%7%12%24%18%4
1800
May1st to 10thNight
37%8%15%24%14%3
1620
11th to 20thNight
36%9%17%25%9%4
1515
21st to endNight
32%8%22%20%11%7%
1552
June1st to 10thNight
23%8%24%26%14%6%
1440
11th to 20thNight
24%7%15%22%20%12%
1440
21st to endNight
26%8%12%26%21%7%
1440
July1st to 10thNight
32%8%13%23%18%6%
1400
11th to 20thNight
24%9%12%26%20%8%
1392
21st to endNight
30%10%20%21%17%3
1488
August1st to 10thNight
33%11%19%21%11%5%
1625
11th to 20thNight
26%7%12%28%21%6%
1778
21st to endNight
23%6%13%26%21%10%
1980
September1st to 10thNight
24%5%13%21%25%13%
1800
11th to 20thNight
20%6%11%23%25%14%
1870
21st to endNight
22%48%23%31%12%
1980
October1st to 10thNight
27%5%10%18%28%12%
2056
11th to 20thNight
18%5%9%24%29%16%
2160
21st to endNight
24%49%24%25%14%
2485
November1st to 10thNight
18%49%25%28%15%
2405
11th to 20thNight
22%39%27%30%10%
2470
21st to endNight
26%47%22%29%11%
2474
December1st to 10thNight
26%5%12%26%23%8%
2660
11th to 20thNight
25%49%25%31%6%
3272
21st to endNight
33%49%26%23%5%
4873

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 10thDay
48%23%42%17%5%
270
11th to 20thDay
10%9%25%40%15%1
255
21st to endDay
7%6%40%34%10%2
264
February1st to 10thDay
5%13%39%34%8%2
240
11th to 20thDay
411%37%37%9%2
240
21st to endDay
5%14%39%29%13%1
198
March1st to 10thDay
7%11%31%30%18%4
240
11th to 20thDay
8%15%34%28%12%2
313
21st to endDay
15%15%32%27%10%1
462
April1st to 10thDay
13%15%33%24%13%3
420
11th to 20thDay
15%21%29%23%10%2
412
21st to endDay
17%15%30%22%13%3
420
May1st to 10thDay
14%11%30%30%12%3
601
11th to 20thDay
15%8%25%32%14%5%
625
21st to endDay
11%10%25%28%20%6%
679
June1st to 10thDay
9%6%20%29%24%12%
630
11th to 20thDay
6%8%26%33%23%4
630
21st to endDay
4324%36%23%9%
630
July1st to 10thDay
6%413%36%29%11%
621
11th to 20thDay
4213%33%33%15%
618
21st to endDay
6%212%34%33%13%
684
August1st to 10thDay
5%214%34%33%13%
488
11th to 20thDay
3322%32%27%14%
437
21st to endDay
3223%36%26%10%
495
September1st to 10thDay
6%220%35%24%13%
450
11th to 20thDay
5%320%32%26%14%
378
21st to endDay
9%319%26%27%16%
270
October1st to 10thDay
11%5%20%24%20%19%
270
11th to 20thDay
37%29%31%21%9%
270
21st to endDay
11%9%25%31%18%6%
297
November1st to 10thDay
48%29%34%21%4
270
11th to 20thDay
6%6%29%38%17%4
270
21st to endDay
7%9%27%36%16%4
270
December1st to 10thDay
7%12%30%31%17%2
270
11th to 20thDay
9%5%32%37%16%1
270
21st to endDay
7%9%35%37%11%1
297
January1st to 10thNight
5%5%34%42%11%2
950
11th to 20thNight
6%8%34%41%11%1
926
21st to endNight
7%5%38%40%10%1
831
February1st to 10thNight
6%5%47%36%5%1
720
11th to 20thNight
6%7%41%39%6%
704
21st to endNight
5%8%42%40%41
592
March1st to 10thNight
6%8%38%40%7%1
720
11th to 20thNight
10%6%40%36%8%
720
21st to endNight
10%8%40%35%6%
608
April1st to 10thNight
11%9%46%30%4
540
11th to 20thNight
16%8%37%35%4
533
21st to endNight
16%7%34%36%6%1
540
May1st to 10thNight
15%9%30%36%10%
540
11th to 20thNight
15%5%31%37%11%1
531
21st to endNight
11%8%34%35%11%1
584
June1st to 10thNight
6%430%43%17%1
540
11th to 20thNight
7%438%40%11%
540
21st to endNight
4228%47%17%1
540
July1st to 10thNight
7%326%42%20%2
525
11th to 20thNight
4120%46%27%2
522
21st to endNight
6%216%48%27%2
591
August1st to 10thNight
7%116%51%24%1
537
11th to 20thNight
7%126%46%18%1
534
21st to endNight
5%125%51%17%2
594
September1st to 10thNight
8%225%47%16%2
540
11th to 20thNight
7%227%47%16%2
540
21st to endNight
6%328%45%17%1
540
October1st to 10thNight
13%5%31%34%15%2
616
11th to 20thNight
6%5%30%44%14%2
720
21st to endNight
10%5%29%40%14%1
901
November1st to 10thNight
46%33%44%12%1
925
11th to 20thNight
5%6%38%41%9%1
950
21st to endNight
8%8%29%41%13%1
950
December1st to 10thNight
5%5%38%40%10%1
950
11th to 20thNight
6%6%36%40%11%1
950
21st to endNight
8%8%36%39%8%
1045
Page generated at 2024-01-12 23:38:12. Version ac07

Copyright 2024 Attilla Danko


Kline-Dodge Dark Sky Site Clear Sky Chart |Charts Home