Waverly
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Waverly clear sky chart from 2005-11-06 to 2024-03-01.

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
41%
24694
21%
80303
14%
24586
49%
24586
27%
50266

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
28%
943
16%
4140
7%
926
39%
926
16%
2802
January11th to 20thNight
24%
949
17%
4033
7%
930
32%
930
15%
2798
January21st to endNight
26%
1036
13%
4484
6%
1023
34%
1023
14%
3236
February1st to 10thNight
23%
950
16%
2470
5%
950
29%
950
23%
1751
February11th to 20thNight
28%
929
18%
2404
6%
925
35%
925
26%
1633
February21st to endNight
20%
615
22%
1871
6%
615
33%
615
25%
1183
March1st to 10thNight
27%
542
24%
1986
11%
542
41%
542
24%
1166
March11th to 20thNight
32%
540
18%
1980
13%
540
40%
540
19%
1275
March21st to endNight
22%
594
11%
2178
6%
594
31%
594
14%
1527
April1st to 10thNight
33%
540
22%
1825
14%
540
47%
540
27%
1063
April11th to 20thNight
33%
533
22%
1775
17%
533
45%
533
26%
1071
April21st to endNight
33%
540
20%
1751
12%
540
46%
540
24%
1129
May1st to 10thNight
39%
540
17%
1620
12%
540
47%
540
26%
1049
May11th to 20thNight
46%
531
18%
1581
16%
531
51%
531
28%
1003
May21st to endNight
47%
584
20%
1552
12%
582
53%
582
30%
1032
June1st to 10thNight
66%
540
22%
1440
15%
540
70%
540
45%
823
June11th to 20thNight
60%
540
24%
1440
14%
540
64%
540
41%
860
June21st to endNight
63%
540
26%
1440
15%
540
67%
540
49%
788
July1st to 10thNight
73%
525
19%
1408
16%
525
73%
525
42%
830
July11th to 20thNight
73%
522
23%
1566
20%
522
77%
522
47%
812
July21st to endNight
71%
591
23%
1673
23%
558
74%
558
40%
927
August1st to 10thNight
75%
537
21%
1601
24%
534
78%
534
42%
885
August11th to 20thNight
73%
534
29%
1601
31%
534
76%
534
42%
866
August21st to endNight
76%
594
28%
1980
35%
594
78%
594
42%
999
September1st to 10thNight
66%
540
27%
1800
29%
540
69%
540
37%
975
September11th to 20thNight
65%
540
31%
1863
30%
540
70%
540
37%
975
September21st to endNight
61%
586
28%
2026
25%
586
68%
586
37%
1054
October1st to 10thNight
51%
720
25%
2160
18%
720
55%
720
38%
1202
October11th to 20thNight
36%
720
28%
2160
16%
720
46%
720
33%
1255
October21st to endNight
33%
792
25%
2376
12%
792
44%
792
29%
1448
November1st to 10thNight
42%
740
29%
2222
17%
740
54%
740
36%
1230
November11th to 20thNight
35%
876
26%
2586
12%
876
47%
876
33%
1518
November21st to endNight
31%
950
22%
2660
9%
950
42%
950
29%
1708
December1st to 10thNight
30%
950
20%
2660
8%
950
40%
950
27%
1724
December11th to 20thNight
30%
949
19%
3153
9%
948
38%
948
22%
1994
December21st to endNight
23%
1042
12%
4838
7%
1026
35%
1026
11%
3675

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%3445%7%42%
78590
Night
13%7%36%43445%6%45%
80862
TransparencyDay
41%5%13%24%14%2
78308
Night
40%5%11%25%16%3
80664
SeeingDay
14%8%26%28%18%5%
14658
Night
15%8%30%33%13%1
24715

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
14%10%410%6%34447%33%
2759
11th to 20thDay
11%11%48%6%48%43435%
2850
21st to endDay
16%15%6%10%6%35%435%28%
3135
February1st to 10thDay
16%11%48%5%34347%34%
1710
11th to 20thDay
13%9%5%6%6%3345%7%40%
1664
21st to endDay
13%8%37%6%2445%6%41%
1596
March1st to 10thDay
12%10%46%6%34446%40%
1980
11th to 20thDay
19%10%46%5%25%446%34%
1980
21st to endDay
23%11%48%6%34446%28%
2178
April1st to 10thDay
15%6%36%5%3445%7%43%
2134
11th to 20thDay
16%9%26%5%235%47%40%
2134
21st to endDay
21%8%26%5%35%5%5%6%34%
2206
May1st to 10thDay
16%8%46%6%35%5%5%6%35%
2340
11th to 20thDay
17%7%36%5%245%5%7%39%
2310
21st to endDay
13%6%37%7%35%6%6%8%35%
2725
June1st to 10thDay
7%424436%6%7%10%48%
2520
11th to 20thDay
8%5%26%5%445%6%9%46%
2520
21st to endDay
6%426%5%35%5%7%9%48%
2520
July1st to 10thDay
9%425%5%35%5%8%9%46%
2506
11th to 20thDay
5%3244345%6%9%53%
2340
21st to endDay
9%5%25%4345%6%9%47%
2546
August1st to 10thDay
7%5%26%5%35%5%6%11%45%
2328
11th to 20thDay
9%425%5%25%5%6%9%47%
2298
21st to endDay
7%4244245%5%9%53%
2376
September1st to 10thDay
12%42342445%7%52%
2160
11th to 20thDay
9%42442445%8%53%
2093
21st to endDay
8%4245%3445%6%56%
1915
October1st to 10thDay
13%424424447%52%
1800
11th to 20thDay
14%7%24423346%52%
1800
21st to endDay
17%8%35%423345%45%
1980
November1st to 10thDay
11%6%24424446%54%
1854
11th to 20thDay
15%7%25%423346%49%
1592
21st to endDay
17%8%47%423335%45%
1520
December1st to 10thDay
10%9%5%7%6%34446%42%
1520
11th to 20thDay
13%9%47%6%345%45%41%
1918
21st to endDay
17%14%7%11%6%3444425%
2783
January1st to 10thNight
10%9%5%13%7%4443437%
4192
11th to 20thNight
13%10%5%8%6%5%6%6%5%433%
4120
21st to endNight
17%13%6%9%5%34435%31%
4532
February1st to 10thNight
14%9%5%7%6%44446%37%
2470
11th to 20thNight
13%7%46%5%34446%42%
2403
21st to endNight
14%8%37%423446%44%
1871
March1st to 10thNight
13%8%35%433347%47%
1986
11th to 20thNight
18%7%35%5%3445%6%38%
1980
21st to endNight
22%10%47%5%44446%30%
2178
April1st to 10thNight
11%7%25%42445%6%50%
1825
11th to 20thNight
15%6%36%424346%47%
1775
21st to endNight
17%7%35%43445%6%42%
1751
May1st to 10thNight
15%5%36%5%2446%9%40%
1620
11th to 20thNight
14%6%3442445%8%46%
1580
21st to endNight
11%5%36%5%35%5%7%9%41%
1551
June1st to 10thNight
5%32342446%10%55%
1440
11th to 20thNight
6%3245%345%6%10%51%
1440
21st to endNight
4314335%46%9%58%
1440
July1st to 10thNight
8%414425%5%6%10%52%
1448
11th to 20thNight
4313425%5%6%9%60%
1620
21st to endNight
6%424435%47%9%51%
1772
August1st to 10thNight
5%324435%6%7%9%54%
1611
11th to 20thNight
6%42433446%8%56%
1601
21st to endNight
6%313425%447%60%
1980
September1st to 10thNight
10%424423447%56%
1800
11th to 20thNight
10%42332445%7%55%
1863
21st to endNight
7%42442445%6%58%
2026
October1st to 10thNight
10%5%2432445%6%56%
2160
11th to 20thNight
14%5%245%22345%54%
2160
21st to endNight
16%7%2432343451%
2376
November1st to 10thNight
11%5%23423346%59%
2222
11th to 20thNight
12%5%35%423446%53%
2586
21st to endNight
17%8%34423345%48%
2660
December1st to 10thNight
13%8%45%5%345%5%6%44%
2660
11th to 20thNight
14%7%37%43445%6%43%
3279
21st to endNight
21%16%5%9%5%2333428%
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
51%411%24%10%1
2760
11th to 20thDay
55%312%21%9%
2850
21st to endDay
59%311%16%10%1
3135
February1st to 10thDay
51%412%21%11%1
1710
11th to 20thDay
45%5%12%22%13%3
1673
21st to endDay
44%5%12%22%15%3
1596
March1st to 10thDay
45%5%12%23%12%3
1980
11th to 20thDay
53%49%22%10%2
1980
21st to endDay
58%413%17%7%1
2178
April1st to 10thDay
41%5%13%26%14%1
2134
11th to 20thDay
45%5%12%23%13%2
2134
21st to endDay
51%5%12%22%10%
2206
May1st to 10thDay
49%7%12%21%11%1
2340
11th to 20thDay
45%6%13%23%12%
2314
21st to endDay
46%7%14%21%10%2
2725
June1st to 10thDay
29%8%17%31%14%1
2520
11th to 20thDay
33%8%13%28%17%2
2520
21st to endDay
30%7%17%30%13%4
2520
July1st to 10thDay
32%7%17%26%15%4
2437
11th to 20thDay
27%8%16%27%18%3
2271
21st to endDay
32%7%14%32%15%1
2405
August1st to 10thDay
33%8%19%25%14%1
2314
11th to 20thDay
33%7%12%31%16%1
2298
21st to endDay
28%6%14%26%20%6%
2376
September1st to 10thDay
31%5%12%28%17%6%
2160
11th to 20thDay
29%5%13%25%25%3
2093
21st to endDay
29%5%10%30%22%3
1915
October1st to 10thDay
33%411%27%22%3
1800
11th to 20thDay
36%37%28%22%4
1800
21st to endDay
42%39%22%18%4
1980
November1st to 10thDay
33%314%27%19%4
1854
11th to 20thDay
38%310%26%20%3
1592
21st to endDay
44%39%27%16%1
1520
December1st to 10thDay
43%413%26%13%1
1520
11th to 20thDay
46%414%26%9%1
1915
21st to endDay
63%49%15%7%1
2783
January1st to 10thNight
52%312%22%11%1
4192
11th to 20thNight
53%412%20%11%1
4120
21st to endNight
56%411%19%9%1
4532
February1st to 10thNight
48%5%12%20%13%3
2470
11th to 20thNight
44%411%21%17%3
2404
21st to endNight
41%410%21%18%5%
1871
March1st to 10thNight
39%410%26%18%3
1986
11th to 20thNight
46%410%22%14%3
1980
21st to endNight
55%413%18%8%1
2178
April1st to 10thNight
35%5%10%26%19%4
1825
11th to 20thNight
39%49%28%16%4
1775
21st to endNight
43%410%24%17%1
1751
May1st to 10thNight
41%6%14%23%14%2
1620
11th to 20thNight
38%7%14%23%17%1
1581
21st to endNight
39%7%13%26%13%2
1552
June1st to 10thNight
25%6%16%32%18%3
1440
11th to 20thNight
27%8%12%28%20%5%
1440
21st to endNight
22%5%15%33%19%5%
1440
July1st to 10thNight
28%6%14%31%18%3
1408
11th to 20thNight
21%6%14%33%22%3
1566
21st to endNight
26%6%13%37%16%1
1673
August1st to 10thNight
25%7%20%29%17%2
1601
11th to 20thNight
27%411%33%24%1
1601
21st to endNight
23%6%11%28%25%7%
1980
September1st to 10thNight
29%5%11%25%24%7%
1800
11th to 20thNight
27%6%10%27%25%5%
1863
21st to endNight
27%5%9%28%26%4
2026
October1st to 10thNight
29%5%10%25%25%6%
2160
11th to 20thNight
34%36%28%21%7%
2160
21st to endNight
38%39%22%23%4
2376
November1st to 10thNight
29%412%26%22%6%
2222
11th to 20thNight
34%38%27%24%4
2586
21st to endNight
41%310%27%17%2
2660
December1st to 10thNight
42%413%26%14%1
2660
11th to 20thNight
43%312%29%12%1
3281
21st to endNight
62%49%16%8%2
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
19%15%33%25%7%
270
11th to 20thDay
30%15%34%19%3
270
21st to endDay
16%15%41%22%6%
297
February1st to 10thDay
25%12%41%18%3
270
11th to 20thDay
18%18%37%20%7%
270
21st to endDay
15%20%42%18%4
225
March1st to 10thDay
17%17%43%19%4
240
11th to 20thDay
30%10%31%25%5%
240
21st to endDay
36%19%30%12%3
264
April1st to 10thDay
19%16%31%25%8%1
394
11th to 20thDay
19%14%33%24%8%1
412
21st to endDay
23%12%32%22%10%1
466
May1st to 10thDay
17%12%35%25%10%1
603
11th to 20thDay
20%8%28%27%14%2
625
21st to endDay
15%8%24%29%19%6%
679
June1st to 10thDay
7%417%32%29%10%
630
11th to 20thDay
9%223%34%27%5%
630
21st to endDay
5%6%29%38%19%4
630
July1st to 10thDay
11%311%27%32%16%
621
11th to 20thDay
5%217%33%33%10%
618
21st to endDay
8%212%33%35%10%
684
August1st to 10thDay
6%215%38%32%8%
626
11th to 20thDay
8%316%34%31%8%
612
21st to endDay
9%112%29%35%14%
495
September1st to 10thDay
13%214%33%31%8%
450
11th to 20thDay
8%215%34%30%11%
383
21st to endDay
10%5%23%31%24%7%
270
October1st to 10thDay
15%6%28%28%15%9%
270
11th to 20thDay
10%16%40%23%10%1
270
21st to endDay
26%16%31%20%7%
297
November1st to 10thDay
18%6%35%26%10%6%
270
11th to 20thDay
15%18%30%24%11%2
270
21st to endDay
24%13%29%27%7%
270
December1st to 10thDay
12%16%36%25%8%3
270
11th to 20thDay
21%12%36%21%9%1
270
21st to endDay
22%19%38%20%1
297
January1st to 10thNight
14%11%40%27%8%
950
11th to 20thNight
18%13%39%25%6%1
950
21st to endNight
16%12%39%29%4
1045
February1st to 10thNight
17%11%43%25%4
950
11th to 20thNight
16%12%37%31%4
929
21st to endNight
19%13%45%20%3
615
March1st to 10thNight
17%12%42%26%4
542
11th to 20thNight
19%10%34%30%6%1
540
21st to endNight
28%12%34%21%5%
594
April1st to 10thNight
15%12%36%31%5%
540
11th to 20thNight
17%11%34%29%8%
533
21st to endNight
19%8%37%28%8%
540
May1st to 10thNight
17%8%30%36%8%1
540
11th to 20thNight
16%5%27%35%15%1
531
21st to endNight
13%7%25%33%20%2
584
June1st to 10thNight
7%318%46%23%4
540
11th to 20thNight
7%322%45%21%2
540
21st to endNight
4324%49%20%1
540
July1st to 10thNight
9%39%40%36%4
525
11th to 20thNight
5%214%42%35%2
522
21st to endNight
7%112%43%36%1
591
August1st to 10thNight
6%211%46%34%2
537
11th to 20thNight
8%111%43%34%3
534
21st to endNight
7%210%41%38%3
594
September1st to 10thNight
11%214%41%28%4
540
11th to 20thNight
12%117%38%27%5%
540
21st to endNight
8%423%40%22%3
586
October1st to 10thNight
13%429%34%19%2
720
11th to 20thNight
16%9%35%31%8%
720
21st to endNight
20%11%33%27%9%
792
November1st to 10thNight
13%8%33%36%10%
740
11th to 20thNight
15%11%36%30%9%
876
21st to endNight
21%10%35%29%5%
950
December1st to 10thNight
17%10%39%29%6%1
950
11th to 20thNight
20%9%34%33%5%
950
21st to endNight
22%13%36%26%4
1045
Page generated at 2024-02-27 05:30:14. Version ac07

Copyright © 2024 Attilla Danko.


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