Lee & Rose Warner Nature Center
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Lee & Rose Warner Nature Center clear sky chart from 2005-11-06 to 2024-01-17.

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%
24881
16%
74749
9%
24824
42%
24824
23%
50187

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
27%
950
13%
2648
6%
946
34%
946
20%
1936
January11th to 20thNight
25%
935
10%
2617
5%
935
29%
935
16%
1984
January21st to endNight
23%
990
11%
2589
3%
990
28%
990
16%
2016
February1st to 10thNight
25%
900
15%
2340
3%
900
32%
900
21%
1679
February11th to 20thNight
27%
879
17%
2274
6%
875
34%
875
25%
1571
February21st to endNight
27%
669
16%
1853
5%
669
36%
669
19%
1341
March1st to 10thNight
29%
626
15%
2066
10%
626
34%
626
19%
1410
March11th to 20thNight
31%
540
19%
1980
13%
540
42%
540
20%
1264
March21st to endNight
34%
594
17%
2138
14%
594
42%
594
18%
1427
April1st to 10thNight
28%
540
16%
1800
11%
540
37%
540
20%
1208
April11th to 20thNight
29%
533
17%
1775
12%
533
39%
533
18%
1244
April21st to endNight
32%
540
17%
1628
11%
540
39%
540
20%
1137
May1st to 10thNight
32%
540
15%
1494
8%
540
38%
540
24%
1040
May11th to 20thNight
39%
531
19%
1417
10%
531
44%
531
30%
942
May21st to endNight
46%
583
14%
1552
7%
582
50%
582
29%
1027
June1st to 10thNight
50%
540
15%
1440
7%
540
55%
540
37%
880
June11th to 20thNight
48%
540
15%
1440
7%
540
52%
540
36%
909
June21st to endNight
57%
540
17%
1440
9%
540
59%
540
42%
854
July1st to 10thNight
65%
525
18%
1400
9%
525
67%
525
49%
775
July11th to 20thNight
60%
522
20%
1392
10%
522
62%
522
46%
784
July21st to endNight
67%
591
23%
1487
12%
558
71%
558
53%
803
August1st to 10thNight
67%
537
21%
1589
19%
534
69%
534
37%
908
August11th to 20thNight
60%
534
23%
1600
20%
534
66%
534
37%
903
August21st to endNight
57%
594
23%
1906
23%
594
63%
594
36%
1065
September1st to 10thNight
56%
540
23%
1800
23%
540
63%
540
33%
990
September11th to 20thNight
51%
540
27%
1800
21%
540
61%
540
36%
966
September21st to endNight
40%
625
20%
2061
13%
625
49%
625
30%
1197
October1st to 10thNight
42%
720
22%
2160
14%
720
48%
720
31%
1306
October11th to 20thNight
31%
720
20%
2160
10%
720
40%
720
23%
1412
October21st to endNight
31%
792
17%
2423
10%
792
38%
792
19%
1667
November1st to 10thNight
31%
835
21%
2501
11%
835
41%
835
24%
1630
November11th to 20thNight
25%
950
15%
2660
7%
950
32%
950
18%
1948
November21st to endNight
27%
950
16%
2660
7%
950
35%
950
21%
1865
December1st to 10thNight
26%
950
11%
2660
4%
950
32%
950
17%
1985
December11th to 20thNight
19%
948
12%
3197
4%
948
26%
948
12%
2404
December21st to endNight
19%
1038
6%
4802
3%
1026
25%
1026
7%
3710

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%9%47%6%35%5%5%7%37%
74759
Night
13%9%47%6%3445%7%39%
75095
TransparencyDay
47%414%24%10%1
74459
Night
46%413%24%12%1
74915
SeeingDay
17%9%30%27%14%4
14858
Night
17%9%31%32%11%1
24891

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%11%7%9%8%5%6%5%5%6%29%
1517
11th to 20thDay
10%14%8%11%9%5%6%5%5%6%22%
1488
21st to endDay
9%13%6%14%9%36%5%6%7%22%
1764
February1st to 10thDay
8%11%5%9%7%5%5%6%6%7%31%
1620
11th to 20thDay
9%12%6%9%6%5%45%5%6%34%
1574
21st to endDay
11%11%6%9%6%36%5%47%30%
1401
March1st to 10thDay
14%12%5%8%7%44447%32%
1908
11th to 20thDay
15%9%46%6%4445%7%37%
1980
21st to endDay
19%12%47%5%345%5%7%29%
2218
April1st to 10thDay
16%10%46%6%3445%7%34%
2160
11th to 20thDay
20%12%46%5%34345%32%
2134
21st to endDay
21%11%35%5%45%5%46%31%
2330
May1st to 10thDay
17%8%37%7%35%45%7%34%
2466
11th to 20thDay
18%7%35%5%34448%39%
2479
21st to endDay
13%7%26%6%35%5%6%8%38%
2725
June1st to 10thDay
13%424435%5%7%9%45%
2520
11th to 20thDay
12%6%35%6%35%6%6%8%38%
2520
21st to endDay
10%5%25%5%36%6%7%9%42%
2520
July1st to 10thDay
7%414435%5%7%10%49%
2520
11th to 20thDay
9%315%435%46%9%50%
2520
21st to endDay
7%325%5%36%6%6%10%48%
2743
August1st to 10thDay
9%5%25%6%46%6%6%9%41%
2338
11th to 20thDay
13%5%245%345%6%7%45%
2301
21st to endDay
10%425%43345%8%52%
2448
September1st to 10thDay
12%5%25%4345%6%9%45%
2160
11th to 20thDay
13%5%24445%6%6%7%45%
2160
21st to endDay
15%6%25%5%35%5%6%7%41%
1877
October1st to 10thDay
17%7%25%43445%6%43%
1800
11th to 20thDay
15%11%36%5%445%5%6%37%
1800
21st to endDay
18%11%5%7%5%23346%36%
1931
November1st to 10thDay
11%12%5%8%5%45%45%5%37%
1576
11th to 20thDay
13%13%7%9%8%3446%5%28%
1520
21st to endDay
15%10%47%7%245%5%8%34%
1520
December1st to 10thDay
11%13%6%10%10%45%5%5%5%26%
1520
11th to 20thDay
11%13%8%10%8%45%445%28%
1918
21st to endDay
21%17%7%14%6%2443319%
2783
January1st to 10thNight
8%11%6%8%8%36%5%6%6%31%
2648
11th to 20thNight
11%12%6%10%8%35%5%6%6%27%
2617
21st to endNight
13%13%6%11%9%445%5%6%25%
2589
February1st to 10thNight
5%11%6%10%8%46%45%6%34%
2340
11th to 20thNight
6%10%5%8%6%5%6%45%8%38%
2273
21st to endNight
12%10%48%7%45%446%35%
1853
March1st to 10thNight
12%10%5%8%6%3445%6%37%
2066
11th to 20thNight
13%10%47%5%24346%41%
1980
21st to endNight
18%9%46%5%34347%36%
2138
April1st to 10thNight
17%11%36%5%3446%6%36%
1800
11th to 20thNight
22%9%47%434445%34%
1775
21st to endNight
20%9%35%6%3445%7%34%
1628
May1st to 10thNight
17%9%36%5%245%5%5%38%
1494
11th to 20thNight
15%5%35%5%25%46%7%43%
1416
21st to endNight
11%5%37%6%35%5%7%8%41%
1551
June1st to 10thNight
11%5%24435%6%6%8%47%
1440
11th to 20thNight
8%5%26%5%36%46%7%48%
1440
21st to endNight
6%415%5%35%5%6%8%52%
1440
July1st to 10thNight
5%31332447%10%56%
1440
11th to 20thNight
5%3244246%7%10%54%
1440
21st to endNight
3322335%47%9%59%
1575
August1st to 10thNight
7%425%5%35%5%7%8%50%
1598
11th to 20thNight
13%42342446%8%52%
1600
21st to endNight
7%425%435%45%6%55%
1906
September1st to 10thNight
10%425%43445%7%53%
1800
11th to 20thNight
10%5%1443345%7%54%
1800
21st to endNight
15%5%235%33447%49%
2061
October1st to 10thNight
15%6%25%33345%6%48%
2160
11th to 20thNight
18%8%245%3445%6%40%
2160
21st to endNight
18%10%47%434446%37%
2423
November1st to 10thNight
13%9%46%43445%6%41%
2501
11th to 20thNight
14%10%5%10%7%4445%5%33%
2660
21st to endNight
14%8%48%6%3445%7%36%
2660
December1st to 10thNight
10%13%5%11%8%35%35%6%31%
2660
11th to 20thNight
12%14%5%11%8%45%45%6%27%
3279
21st to endNight
22%14%6%11%6%34345%22%
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
56%5%12%21%6%
1518
11th to 20thDay
64%410%13%8%
1488
21st to endDay
61%5%13%14%7%
1764
February1st to 10thDay
53%415%20%8%1
1620
11th to 20thDay
52%412%23%9%1
1583
21st to endDay
54%5%10%21%10%1
1401
March1st to 10thDay
54%316%19%7%1
1908
11th to 20thDay
48%414%24%8%1
1980
21st to endDay
55%5%10%22%8%1
2218
April1st to 10thDay
49%411%22%12%1
2160
11th to 20thDay
55%39%19%12%2
2134
21st to endDay
55%412%19%9%
2330
May1st to 10thDay
50%412%22%10%2
2466
11th to 20thDay
45%414%24%11%1
2483
21st to endDay
45%411%26%12%1
2725
June1st to 10thDay
35%5%16%31%11%1
2520
11th to 20thDay
42%6%14%25%13%1
2520
21st to endDay
37%6%17%30%9%2
2520
July1st to 10thDay
29%6%17%34%14%1
2451
11th to 20thDay
31%6%16%28%18%2
2445
21st to endDay
31%6%17%29%16%1
2591
August1st to 10thDay
38%5%16%29%9%2
2323
11th to 20thDay
37%5%15%32%11%1
2301
21st to endDay
32%415%31%17%1
2448
September1st to 10thDay
36%6%13%32%13%
2160
11th to 20thDay
37%5%17%32%8%
2160
21st to endDay
42%412%33%9%
1877
October1st to 10thDay
42%412%30%11%1
1800
11th to 20thDay
48%414%22%10%2
1800
21st to endDay
52%313%22%10%
1931
November1st to 10thDay
50%413%19%12%2
1576
11th to 20thDay
58%413%16%8%1
1520
21st to endDay
50%417%21%6%2
1520
December1st to 10thDay
61%5%14%16%4
1520
11th to 20thDay
60%218%15%5%
1915
21st to endDay
72%38%11%6%
2783
January1st to 10thNight
53%413%20%8%1
2648
11th to 20thNight
58%415%15%6%
2617
21st to endNight
60%312%15%8%1
2589
February1st to 10thNight
50%412%24%9%1
2340
11th to 20thNight
45%415%26%8%2
2274
21st to endNight
53%410%21%11%1
1853
March1st to 10thNight
50%414%23%9%1
2066
11th to 20thNight
46%313%22%14%1
1980
21st to endNight
49%412%23%11%1
2138
April1st to 10thNight
49%48%23%15%1
1800
11th to 20thNight
53%37%20%14%2
1775
21st to endNight
50%5%9%21%14%2
1628
May1st to 10thNight
47%413%20%15%1
1494
11th to 20thNight
40%6%12%26%14%3
1417
21st to endNight
41%5%14%22%17%2
1552
June1st to 10thNight
32%5%15%30%17%1
1440
11th to 20thNight
35%5%15%25%17%3
1440
21st to endNight
29%5%16%32%15%3
1440
July1st to 10thNight
24%416%35%20%2
1400
11th to 20thNight
24%6%16%33%18%4
1392
21st to endNight
21%418%33%19%5%
1487
August1st to 10thNight
31%5%14%31%15%4
1589
11th to 20thNight
31%417%30%16%2
1600
21st to endNight
31%5%14%30%17%4
1906
September1st to 10thNight
31%5%13%34%17%1
1800
11th to 20thNight
30%416%34%16%
1800
21st to endNight
36%315%33%12%1
2061
October1st to 10thNight
37%310%33%14%2
2160
11th to 20thNight
46%313%25%13%1
2160
21st to endNight
50%412%23%10%1
2423
November1st to 10thNight
44%312%25%14%1
2501
11th to 20thNight
54%412%18%11%1
2660
21st to endNight
49%416%23%7%1
2660
December1st to 10thNight
57%313%20%6%
2660
11th to 20thNight
60%412%17%6%1
3281
21st to endNight
67%212%15%4
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
15%13%33%27%9%3
270
11th to 20thDay
19%10%40%25%7%
258
21st to endDay
17%8%39%25%9%2
264
February1st to 10thDay
16%15%48%18%3
240
11th to 20thDay
16%16%43%18%6%1
240
21st to endDay
19%15%36%27%3
198
March1st to 10thDay
19%12%43%17%9%1
240
11th to 20thDay
16%12%39%23%8%2
240
21st to endDay
25%14%29%20%9%3
304
April1st to 10thDay
22%14%34%24%5%1
420
11th to 20thDay
30%10%23%26%10%1
412
21st to endDay
26%12%29%20%11%2
590
May1st to 10thDay
22%12%29%26%9%2
603
11th to 20thDay
21%12%27%24%13%4
625
21st to endDay
17%9%26%28%16%4
679
June1st to 10thDay
10%7%28%32%18%5%
630
11th to 20thDay
15%7%33%31%12%3
630
21st to endDay
13%7%29%29%17%6%
630
July1st to 10thDay
8%421%32%25%10%
621
11th to 20thDay
9%6%26%31%20%8%
618
21st to endDay
7%424%35%21%7%
684
August1st to 10thDay
10%421%34%25%6%
626
11th to 20thDay
14%420%30%25%7%
615
21st to endDay
11%5%24%35%20%5%
567
September1st to 10thDay
15%7%28%28%16%5%
450
11th to 20thDay
12%5%28%32%20%3
450
21st to endDay
18%14%29%23%11%4
270
October1st to 10thDay
19%11%27%24%15%4
270
11th to 20thDay
20%20%30%21%7%1
270
21st to endDay
25%13%38%18%5%1
297
November1st to 10thDay
18%14%34%23%9%1
270
11th to 20thDay
19%17%39%21%4
270
21st to endDay
24%11%40%19%5%
270
December1st to 10thDay
16%10%44%20%9%1
270
11th to 20thDay
21%14%36%23%6%
270
21st to endDay
29%15%36%18%11
297
January1st to 10thNight
13%11%35%32%8%1
950
11th to 20thNight
17%11%35%30%7%1
935
21st to endNight
19%10%34%29%7%1
990
February1st to 10thNight
12%12%40%29%7%1
900
11th to 20thNight
13%13%39%28%7%1
879
21st to endNight
19%13%32%29%7%
669
March1st to 10thNight
16%11%36%28%9%1
626
11th to 20thNight
19%8%38%29%6%
540
21st to endNight
22%10%29%27%10%2
594
April1st to 10thNight
22%11%33%26%7%
540
11th to 20thNight
27%7%31%27%8%
533
21st to endNight
24%9%29%29%8%1
540
May1st to 10thNight
22%8%31%31%7%1
540
11th to 20thNight
18%6%31%32%11%1
531
21st to endNight
13%7%25%39%15%1
584
June1st to 10thNight
12%427%44%13%1
540
11th to 20thNight
10%431%44%10%1
540
21st to endNight
9%324%46%16%2
540
July1st to 10thNight
6%220%41%29%2
525
11th to 20thNight
7%423%44%20%2
522
21st to endNight
6%222%46%22%2
591
August1st to 10thNight
7%215%51%22%2
537
11th to 20thNight
15%318%35%27%3
534
21st to endNight
9%424%37%24%2
594
September1st to 10thNight
11%5%22%40%18%3
540
11th to 20thNight
11%6%25%36%19%2
540
21st to endNight
17%7%30%31%13%1
625
October1st to 10thNight
19%7%28%32%13%2
720
11th to 20thNight
23%10%30%29%7%1
720
21st to endNight
25%9%28%30%8%
792
November1st to 10thNight
19%10%33%30%7%1
835
11th to 20thNight
19%13%34%27%7%
950
21st to endNight
18%15%35%26%7%
950
December1st to 10thNight
16%11%35%30%7%1
950
11th to 20thNight
20%9%37%26%7%1
950
21st to endNight
25%10%33%26%5%
1045
Page generated at 2024-01-14 08:55:00. Version ac07

Copyright 2024 Attilla Danko


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