Denison
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Denison clear sky chart from 2005-11-06 to 2024-02-15.

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%
24824
19%
80189
11%
24728
44%
24728
25%
51337

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
25%
939
11%
4225
6%
926
35%
926
12%
3315
January11th to 20thNight
23%
949
17%
4009
6%
930
32%
930
13%
2741
January21st to endNight
19%
1032
10%
4505
4%
1023
29%
1023
11%
3404
February1st to 10thNight
24%
950
15%
2470
5%
950
30%
950
22%
1783
February11th to 20thNight
23%
901
17%
2333
6%
897
31%
897
26%
1603
February21st to endNight
23%
642
20%
1826
5%
642
36%
642
24%
1227
March1st to 10thNight
29%
541
20%
1981
12%
541
41%
541
22%
1213
March11th to 20thNight
28%
540
20%
1980
13%
540
39%
540
20%
1242
March21st to endNight
24%
594
11%
2178
7%
594
32%
594
14%
1528
April1st to 10thNight
24%
540
16%
1885
11%
540
34%
540
22%
1153
April11th to 20thNight
26%
533
20%
1706
11%
533
41%
533
22%
1080
April21st to endNight
31%
540
18%
1620
11%
540
43%
540
23%
1085
May1st to 10thNight
35%
540
16%
1620
11%
540
43%
540
26%
1049
May11th to 20thNight
39%
531
17%
1577
10%
531
46%
531
26%
1007
May21st to endNight
40%
584
13%
1552
6%
582
44%
582
27%
1051
June1st to 10thNight
57%
540
21%
1440
10%
540
61%
540
38%
862
June11th to 20thNight
48%
540
20%
1440
8%
540
52%
540
41%
836
June21st to endNight
52%
540
20%
1440
8%
540
56%
540
42%
832
July1st to 10thNight
69%
525
19%
1400
10%
525
70%
525
49%
769
July11th to 20thNight
68%
522
23%
1547
15%
522
72%
522
52%
765
July21st to endNight
71%
591
24%
1673
22%
558
73%
558
48%
857
August1st to 10thNight
62%
537
20%
1601
20%
534
65%
534
36%
929
August11th to 20thNight
61%
534
27%
1600
26%
534
67%
534
41%
868
August21st to endNight
61%
594
25%
1845
25%
594
67%
594
40%
1003
September1st to 10thNight
56%
540
25%
1800
22%
540
64%
540
39%
932
September11th to 20thNight
51%
540
27%
1979
26%
540
60%
540
35%
1020
September21st to endNight
44%
540
29%
1980
19%
540
58%
540
35%
995
October1st to 10thNight
41%
697
25%
2137
17%
697
48%
697
31%
1272
October11th to 20thNight
30%
720
25%
2160
10%
720
42%
720
29%
1293
October21st to endNight
32%
792
23%
2376
11%
792
43%
792
26%
1454
November1st to 10thNight
34%
879
27%
2359
10%
879
47%
879
37%
1373
November11th to 20thNight
26%
950
23%
2642
8%
950
38%
950
28%
1655
November21st to endNight
29%
950
22%
2660
11%
950
38%
950
28%
1691
December1st to 10thNight
25%
950
16%
2660
5%
950
35%
950
24%
1793
December11th to 20thNight
25%
949
18%
3160
6%
948
34%
948
19%
2015
December21st to endNight
19%
1038
11%
4823
6%
1026
31%
1026
10%
3642

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%8%37%6%35%5%5%7%39%
78422
Night
11%8%37%5%3445%7%43%
80712
TransparencyDay
44%5%13%24%13%2
78139
Night
42%5%13%24%15%2
80516
SeeingDay
16%9%31%28%13%3
14777
Night
15%9%35%31%10%1
24858

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 10thDay
8%12%5%16%12%5%6%5%45%22%
2719
11th to 20thDay
7%13%6%11%8%5%8%45%7%26%
2850
21st to endDay
10%13%8%16%9%5%4445%20%
3135
February1st to 10thDay
10%12%5%9%8%46%45%8%28%
1710
11th to 20thDay
10%10%5%9%7%35%446%37%
1610
21st to endDay
12%12%49%7%445%5%6%33%
1446
March1st to 10thDay
13%9%49%6%3435%6%39%
1978
11th to 20thDay
14%11%5%8%5%2445%6%35%
1980
21st to endDay
18%14%5%7%7%3445%6%28%
2178
April1st to 10thDay
15%10%36%5%3445%6%38%
2074
11th to 20thDay
18%10%36%5%34446%36%
2202
21st to endDay
21%8%25%5%345%46%36%
2340
May1st to 10thDay
19%8%25%5%36%5%6%7%34%
2340
11th to 20thDay
17%8%35%435%6%5%7%38%
2315
21st to endDay
17%7%36%5%35%5%6%8%35%
2725
June1st to 10thDay
10%5%25%5%45%5%6%9%45%
2520
11th to 20thDay
9%425%5%345%7%10%45%
2520
21st to endDay
8%4345%45%6%6%8%47%
2520
July1st to 10thDay
7%324335%5%7%10%49%
2520
11th to 20thDay
7%3244345%5%8%54%
2357
21st to endDay
6%4245%35%5%7%10%50%
2546
August1st to 10thDay
9%5%35%6%5%6%6%7%9%39%
2328
11th to 20thDay
11%5%25%435%45%8%48%
2301
21st to endDay
10%424425%5%6%8%52%
2509
September1st to 10thDay
13%5%2432445%7%51%
2159
11th to 20thDay
10%5%2432435%9%53%
1980
21st to endDay
12%4133245%5%8%53%
1980
October1st to 10thDay
15%5%25%4235%46%48%
1805
11th to 20thDay
14%5%35%424336%51%
1800
21st to endDay
15%8%36%434445%44%
1980
November1st to 10thDay
9%6%25%5%3445%7%50%
1719
11th to 20thDay
12%7%38%7%2445%8%40%
1535
21st to endDay
13%8%46%42346%7%43%
1520
December1st to 10thDay
10%8%48%8%4445%7%38%
1520
11th to 20thDay
9%10%48%8%45%6%6%7%31%
1918
21st to endDay
17%10%6%17%7%345%45%22%
2783
January1st to 10thNight
9%11%5%18%13%45%445%24%
4232
11th to 20thNight
7%12%5%9%7%47%7%10%6%27%
4120
21st to endNight
10%14%7%13%8%45%445%26%
4532
February1st to 10thNight
11%9%6%8%7%45%35%6%36%
2470
11th to 20thNight
10%9%46%6%35%45%6%40%
2332
21st to endNight
10%8%48%6%35%445%42%
1826
March1st to 10thNight
11%9%46%434447%44%
1981
11th to 20thNight
13%10%46%5%34448%41%
1980
21st to endNight
17%11%47%6%35%45%8%30%
2178
April1st to 10thNight
13%8%26%5%2446%7%43%
1885
11th to 20thNight
13%9%36%5%34447%42%
1706
21st to endNight
17%9%35%5%3445%8%38%
1620
May1st to 10thNight
16%7%35%42446%9%40%
1620
11th to 20thNight
15%5%26%5%3345%7%45%
1576
21st to endNight
12%7%37%435%5%6%8%39%
1551
June1st to 10thNight
6%325%5%35%5%6%8%52%
1440
11th to 20thNight
6%424425%5%6%11%51%
1440
21st to endNight
4324425%5%7%9%55%
1440
July1st to 10thNight
5%32342445%10%58%
1440
11th to 20thNight
32123335%5%9%64%
1599
21st to endNight
3224325%5%6%9%60%
1772
August1st to 10thNight
6%426%425%46%10%50%
1611
11th to 20thNight
8%425%42335%7%58%
1600
21st to endNight
7%3244345%6%8%56%
1845
September1st to 10thNight
9%413423448%58%
1800
11th to 20thNight
9%41443445%6%56%
1979
21st to endNight
11%5%13423346%58%
1980
October1st to 10thNight
14%7%2432335%6%51%
2137
11th to 20thNight
15%7%34323345%51%
2160
21st to endNight
15%8%25%323336%49%
2376
November1st to 10thNight
8%42442445%7%55%
2359
11th to 20thNight
10%7%36%5%3445%6%47%
2642
21st to endNight
12%9%35%424446%47%
2660
December1st to 10thNight
9%9%48%7%35%45%7%39%
2660
11th to 20thNight
10%9%47%6%4445%8%40%
3279
21st to endNight
16%12%6%14%7%2434426%
4884

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
65%411%14%6%1
2720
11th to 20thDay
59%39%23%6%
2850
21st to endDay
66%412%12%5%
3135
February1st to 10thDay
55%5%12%17%10%1
1710
11th to 20thDay
49%411%21%13%2
1619
21st to endDay
52%6%9%21%10%3
1446
March1st to 10thDay
48%412%25%10%2
1978
11th to 20thDay
50%5%11%22%11%2
1980
21st to endDay
58%5%12%17%6%1
2178
April1st to 10thDay
48%5%12%24%10%1
2074
11th to 20thDay
50%5%10%21%11%2
2202
21st to endDay
50%5%9%23%13%
2340
May1st to 10thDay
48%6%13%21%11%
2340
11th to 20thDay
45%7%12%25%10%1
2319
21st to endDay
47%7%13%21%11%2
2725
June1st to 10thDay
36%6%16%27%13%2
2520
11th to 20thDay
33%7%15%27%16%2
2520
21st to endDay
33%7%16%28%13%3
2520
July1st to 10thDay
29%7%15%33%14%3
2451
11th to 20thDay
28%5%15%28%18%5%
2287
21st to endDay
29%7%15%30%17%2
2405
August1st to 10thDay
39%8%15%25%11%1
2314
11th to 20thDay
35%5%12%33%14%1
2301
21st to endDay
30%7%12%26%20%5%
2509
September1st to 10thDay
34%5%11%27%20%3
2159
11th to 20thDay
30%414%33%17%2
1980
21st to endDay
29%413%30%23%1
1980
October1st to 10thDay
37%410%29%18%1
1805
11th to 20thDay
37%49%28%19%4
1800
21st to endDay
43%411%21%18%3
1980
November1st to 10thDay
34%416%24%20%2
1719
11th to 20thDay
44%312%24%16%1
1535
21st to endDay
41%315%26%13%1
1520
December1st to 10thDay
46%5%15%22%10%2
1520
11th to 20thDay
50%6%16%22%5%
1915
21st to endDay
64%5%9%14%7%1
2783
January1st to 10thNight
64%39%14%9%
4232
11th to 20thNight
52%5%13%19%10%2
4120
21st to endNight
62%412%13%8%1
4532
February1st to 10thNight
51%411%22%11%2
2470
11th to 20thNight
45%412%23%13%3
2333
21st to endNight
45%411%20%17%3
1826
March1st to 10thNight
41%5%12%29%11%2
1981
11th to 20thNight
44%5%10%24%15%2
1980
21st to endNight
54%5%14%18%7%2
2178
April1st to 10thNight
41%412%25%16%2
1885
11th to 20thNight
43%413%22%16%2
1706
21st to endNight
45%5%12%23%14%1
1620
May1st to 10thNight
41%6%14%24%14%2
1620
11th to 20thNight
39%7%14%24%16%1
1577
21st to endNight
43%6%18%19%12%3
1552
June1st to 10thNight
30%7%14%32%16%3
1440
11th to 20thNight
27%7%15%26%21%5%
1440
21st to endNight
24%8%15%31%18%3
1440
July1st to 10thNight
23%5%18%32%19%3
1400
11th to 20thNight
17%6%18%34%20%4
1547
21st to endNight
20%6%15%34%22%3
1673
August1st to 10thNight
31%6%16%30%14%3
1601
11th to 20thNight
27%415%30%19%4
1600
21st to endNight
25%7%15%25%21%8%
1845
September1st to 10thNight
27%413%29%23%4
1800
11th to 20thNight
28%5%11%33%21%2
1979
21st to endNight
28%311%32%23%3
1980
October1st to 10thNight
36%410%27%21%2
2137
11th to 20thNight
36%49%25%22%4
2160
21st to endNight
39%413%23%21%2
2376
November1st to 10thNight
29%5%16%25%22%4
2359
11th to 20thNight
38%413%27%17%2
2642
21st to endNight
40%410%29%15%2
2660
December1st to 10thNight
44%5%12%27%11%1
2660
11th to 20thNight
44%415%29%7%
3281
21st to endNight
62%48%19%7%
4884

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
18%15%34%25%7%
270
11th to 20thDay
19%13%41%23%31
270
21st to endDay
19%10%40%24%6%1
297
February1st to 10thDay
18%16%40%24%2
270
11th to 20thDay
17%16%37%24%5%1
252
21st to endDay
23%14%40%21%3
198
March1st to 10thDay
18%15%44%17%5%1
240
11th to 20thDay
25%12%37%20%6%
240
21st to endDay
37%14%30%16%3
264
April1st to 10thDay
24%14%39%19%3
334
11th to 20thDay
27%11%34%20%7%1
480
21st to endDay
27%13%30%22%7%2
600
May1st to 10thDay
24%12%30%23%8%1
603
11th to 20thDay
22%12%29%22%12%4
625
21st to endDay
19%6%31%29%13%2
679
June1st to 10thDay
8%6%26%36%22%3
630
11th to 20thDay
10%7%32%31%16%3
630
21st to endDay
8%8%33%32%16%3
630
July1st to 10thDay
9%319%36%25%9%
621
11th to 20thDay
7%229%39%15%7%
618
21st to endDay
6%323%38%26%3
684
August1st to 10thDay
9%321%39%24%5%
626
11th to 20thDay
12%222%36%24%4
615
21st to endDay
11%421%40%20%6%
628
September1st to 10thDay
14%426%35%16%4
449
11th to 20thDay
7%8%36%29%16%5%
270
21st to endDay
13%7%38%29%11%1
270
October1st to 10thDay
20%9%29%26%14%3
270
11th to 20thDay
17%18%38%20%5%1
270
21st to endDay
22%16%35%21%6%1
297
November1st to 10thDay
16%15%40%19%7%3
270
11th to 20thDay
19%19%39%19%4
270
21st to endDay
21%15%34%24%6%
270
December1st to 10thDay
11%14%40%26%7%1
270
11th to 20thDay
16%16%37%24%7%1
270
21st to endDay
26%16%40%17%2
297
January1st to 10thNight
13%15%38%29%41
950
11th to 20thNight
15%13%40%25%6%1
950
21st to endNight
19%9%40%26%5%
1045
February1st to 10thNight
16%9%44%26%4
950
11th to 20thNight
16%11%43%26%5%
902
21st to endNight
15%12%45%22%5%1
642
March1st to 10thNight
18%12%38%25%7%1
541
11th to 20thNight
20%10%36%27%8%
540
21st to endNight
25%9%34%24%5%1
594
April1st to 10thNight
17%14%42%23%4
540
11th to 20thNight
21%11%37%24%7%
533
21st to endNight
22%11%32%26%9%
540
May1st to 10thNight
20%7%35%30%8%
540
11th to 20thNight
17%8%30%34%11%
531
21st to endNight
16%5%33%33%13%
584
June1st to 10thNight
8%326%46%16%1
540
11th to 20thNight
9%334%40%13%1
540
21st to endNight
6%5%32%41%16%
540
July1st to 10thNight
6%218%47%26%2
525
11th to 20thNight
4123%48%21%2
522
21st to endNight
4217%53%24%1
591
August1st to 10thNight
9%220%43%23%2
537
11th to 20thNight
10%321%40%23%2
534
21st to endNight
8%223%45%19%3
594
September1st to 10thNight
12%424%38%19%3
540
11th to 20thNight
11%332%38%14%2
540
21st to endNight
14%435%34%12%1
540
October1st to 10thNight
17%7%31%32%11%2
697
11th to 20thNight
20%11%36%28%5%
720
21st to endNight
22%12%29%29%8%
792
November1st to 10thNight
11%13%39%29%8%
879
11th to 20thNight
14%14%42%24%5%
950
21st to endNight
18%11%37%25%8%
950
December1st to 10thNight
15%12%40%27%5%
950
11th to 20thNight
17%10%39%28%6%
950
21st to endNight
20%13%38%24%4
1045
Page generated at 2024-02-12 05:35:32. Version ac07

Copyright 2024 Attilla Danko


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