Meadow View Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Meadow View Observatory clear sky chart from 2005-11-06 to 2024-03-08.

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
62%
23509
27%
80544
24%
23421
68%
23421
36%
43995

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
48%
748
17%
4358
15%
736
53%
736
14%
2580
January11th to 20thNight
52%
750
16%
4146
19%
740
59%
740
13%
2794
January21st to endNight
49%
832
15%
4491
24%
814
56%
814
14%
3197
February1st to 10thNight
53%
760
26%
2470
22%
760
61%
760
30%
1451
February11th to 20thNight
51%
741
25%
2343
22%
740
60%
740
29%
1395
February21st to endNight
47%
628
24%
1884
20%
628
54%
628
31%
1141
March1st to 10thNight
41%
750
15%
2151
11%
750
45%
750
21%
1494
March11th to 20thNight
49%
720
23%
1980
17%
720
54%
720
31%
1260
March21st to endNight
45%
792
20%
2120
12%
792
50%
792
31%
1368
April1st to 10thNight
47%
720
23%
1800
11%
720
53%
720
35%
1141
April11th to 20thNight
53%
711
29%
1779
13%
711
59%
711
43%
1046
April21st to endNight
61%
720
27%
1800
12%
720
67%
720
51%
990
May1st to 10thNight
55%
594
29%
1674
15%
594
63%
594
50%
869
May11th to 20thNight
63%
354
30%
1416
29%
354
71%
354
40%
631
May21st to endNight
64%
389
26%
1552
26%
388
71%
388
37%
717
June1st to 10thNight
64%
360
25%
1440
25%
360
74%
360
40%
638
June11th to 20thNight
71%
360
34%
1440
40%
360
80%
360
59%
505
June21st to endNight
78%
360
34%
1440
42%
360
86%
360
64%
482
July1st to 10thNight
85%
350
36%
1400
45%
350
91%
350
80%
411
July11th to 20thNight
84%
348
40%
1392
49%
348
89%
348
77%
416
July21st to endNight
88%
580
41%
1664
36%
548
92%
548
81%
622
August1st to 10thNight
84%
537
39%
1602
32%
534
86%
534
71%
654
August11th to 20thNight
89%
614
41%
1682
27%
614
92%
614
78%
713
August21st to endNight
92%
792
45%
1980
29%
792
93%
792
87%
863
September1st to 10thNight
88%
720
45%
1800
30%
720
91%
720
85%
782
September11th to 20thNight
81%
720
44%
1800
32%
720
84%
720
70%
867
September21st to endNight
77%
720
41%
2036
37%
720
83%
720
71%
871
October1st to 10thNight
69%
720
33%
2160
30%
720
78%
720
57%
986
October11th to 20thNight
72%
720
38%
2160
38%
720
80%
720
56%
1002
October21st to endNight
70%
792
38%
2376
35%
792
77%
792
53%
1141
November1st to 10thNight
62%
740
28%
2351
26%
740
68%
740
36%
1294
November11th to 20thNight
61%
760
24%
2496
22%
760
68%
760
36%
1377
November21st to endNight
59%
760
26%
2660
26%
760
64%
760
33%
1425
December1st to 10thNight
55%
760
23%
2660
21%
760
61%
760
28%
1537
December11th to 20thNight
47%
760
19%
3227
19%
759
54%
759
16%
2232
December21st to endNight
42%
827
13%
4814
16%
817
51%
817
12%
3103

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
11%313323346%62%
78648
Night
13%423323346%57%
80938
TransparencyDay
25%49%18%23%21%
78362
Night
29%5%9%18%21%18%
80745
SeeingDay
11%7%18%28%27%10%
14169
Night
12%417%36%28%3
23547

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
27%7%24423346%37%
2539
11th to 20thDay
28%8%36%423345%35%
2778
21st to endDay
29%7%34413447%34%
3146
February1st to 10thDay
19%5%23324446%48%
1710
11th to 20thDay
17%6%25%323347%49%
1726
21st to endDay
18%5%2332435%7%49%
1570
March1st to 10thDay
21%6%25%42345%7%39%
1967
11th to 20thDay
22%6%14323447%44%
1980
21st to endDay
18%5%2332435%8%47%
2235
April1st to 10thDay
14%5%3442345%8%47%
2160
11th to 20thDay
12%42332245%5%57%
2129
21st to endDay
6%323224348%63%
2160
May1st to 10thDay
6%323323336%66%
2282
11th to 20thDay
5%322323347%66%
2476
21st to endDay
5%31232345%7%65%
2723
June1st to 10thDay
5%31221335%9%64%
2520
11th to 20thDay
2112212235%79%
2520
21st to endDay
211111222485%
2520
July1st to 10thDay
11111123387%
2520
11th to 20thDay
11111112389%
2520
21st to endDay
111111122386%
2554
August1st to 10thDay
211121223383%
2328
11th to 20thDay
1111112388%
2219
21st to endDay
11111111291%
2376
September1st to 10thDay
11111122387%
2160
11th to 20thDay
3212212335%77%
2160
21st to endDay
311211235%80%
1918
October1st to 10thDay
421222233474%
1800
11th to 20thDay
7%312212245%70%
1800
21st to endDay
10%212322447%63%
1980
November1st to 10thDay
14%31332345%7%54%
1728
11th to 20thDay
15%315%32445%8%50%
1682
21st to endDay
13%42332445%6%55%
1520
December1st to 10thDay
20%423223345%52%
1520
11th to 20thDay
32%7%35%5%33336%31%
1928
21st to endDay
23%7%25%424347%37%
2794
January1st to 10thNight
19%7%35%423448%41%
4406
11th to 20thNight
28%5%25%423446%37%
4172
21st to endNight
28%8%26%5%33336%32%
4521
February1st to 10thNight
19%424323447%50%
2470
11th to 20thNight
16%5%2443345%6%48%
2341
21st to endNight
16%5%23424446%50%
1884
March1st to 10thNight
21%7%35%5%33446%39%
2151
11th to 20thNight
19%6%2432345%9%43%
1980
21st to endNight
17%425%42345%6%48%
2120
April1st to 10thNight
11%4344345%6%9%48%
1800
11th to 20thNight
10%423323347%57%
1779
21st to endNight
7%322313347%65%
1800
May1st to 10thNight
7%41332335%7%64%
1674
11th to 20thNight
4313425%5%5%8%61%
1416
21st to endNight
5%41232345%7%62%
1552
June1st to 10thNight
5%21432435%9%62%
1440
11th to 20thNight
212313236%77%
1440
21st to endNight
21122223481%
1440
July1st to 10thNight
1111122388%
1440
11th to 20thNight
111111122188%
1440
21st to endNight
11112212485%
1762
August1st to 10thNight
221121213382%
1611
11th to 20thNight
1111233385%
1682
21st to endNight
11111122390%
1980
September1st to 10thNight
1111112388%
1800
11th to 20thNight
3111212335%77%
1800
21st to endNight
311111245%79%
2036
October1st to 10thNight
5%21221223375%
2160
11th to 20thNight
5%21222334473%
2160
21st to endNight
8%212213246%68%
2376
November1st to 10thNight
13%41332345%7%55%
2351
11th to 20thNight
13%3133235%5%8%54%
2496
21st to endNight
13%423323446%56%
2660
December1st to 10thNight
21%413322347%49%
2660
11th to 20thNight
34%5%23324347%33%
3276
21st to endNight
24%6%25%5%34446%37%
4862

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
49%6%10%26%7%3
2539
11th to 20thDay
53%6%8%14%10%8%
2778
21st to endDay
51%7%12%13%12%5%
3146
February1st to 10thDay
37%6%12%18%20%8%
1710
11th to 20thDay
36%6%9%20%22%7%
1735
21st to endDay
35%5%11%26%17%6%
1570
March1st to 10thDay
45%6%11%19%13%6%
1967
11th to 20thDay
41%411%21%16%7%
1980
21st to endDay
36%7%14%19%18%5%
2235
April1st to 10thDay
36%6%12%22%18%7%
2160
11th to 20thDay
29%5%10%22%24%9%
2132
21st to endDay
21%5%14%29%23%9%
2160
May1st to 10thDay
20%412%22%28%14%
2282
11th to 20thDay
19%5%11%25%28%12%
2479
21st to endDay
19%5%15%29%22%10%
2724
June1st to 10thDay
18%6%11%25%25%15%
2520
11th to 20thDay
8%39%21%31%28%
2520
21st to endDay
7%2414%32%40%
2520
July1st to 10thDay
5%2310%28%51%
2451
11th to 20thDay
5%2311%26%53%
2445
21st to endDay
5%229%24%57%
2412
August1st to 10thDay
8%2412%31%43%
2312
11th to 20thDay
5%1211%35%47%
2219
21st to endDay
41213%33%47%
2376
September1st to 10thDay
4138%26%56%
2160
11th to 20thDay
11%36%20%36%23%
2160
21st to endDay
10%26%21%30%32%
1918
October1st to 10thDay
16%45%18%29%28%
1800
11th to 20thDay
18%38%18%23%30%
1800
21st to endDay
21%5%8%19%27%21%
1980
November1st to 10thDay
29%5%10%23%19%14%
1728
11th to 20thDay
32%8%11%22%18%9%
1682
21st to endDay
30%6%10%20%21%13%
1520
December1st to 10thDay
36%6%9%19%20%11%
1520
11th to 20thDay
58%47%13%13%5%
1928
21st to endDay
46%9%14%17%11%3
2794
January1st to 10thNight
41%9%16%22%9%3
4406
11th to 20thNight
48%9%11%11%13%8%
4172
21st to endNight
55%6%10%11%13%6%
4521
February1st to 10thNight
35%5%9%21%17%13%
2470
11th to 20thNight
35%6%9%19%23%9%
2343
21st to endNight
36%5%9%23%19%8%
1884
March1st to 10thNight
46%8%11%14%17%5%
2151
11th to 20thNight
37%6%10%22%17%9%
1980
21st to endNight
37%7%12%21%18%6%
2120
April1st to 10thNight
33%7%14%20%18%9%
1800
11th to 20thNight
25%6%12%24%21%12%
1779
21st to endNight
20%5%13%26%27%8%
1800
May1st to 10thNight
19%5%11%20%30%14%
1674
11th to 20thNight
21%5%14%25%23%13%
1416
21st to endNight
20%7%12%26%24%9%
1552
June1st to 10thNight
19%7%11%25%25%12%
1440
11th to 20thNight
10%410%19%29%29%
1440
21st to endNight
9%3414%30%41%
1440
July1st to 10thNight
5%1313%25%53%
1400
11th to 20thNight
6%1311%22%57%
1392
21st to endNight
5%129%21%61%
1664
August1st to 10thNight
10%2314%30%42%
1602
11th to 20thNight
6%2311%31%47%
1682
21st to endNight
41311%32%48%
1980
September1st to 10thNight
5%227%28%57%
1800
11th to 20thNight
11%36%17%36%27%
1800
21st to endNight
9%35%16%31%36%
2036
October1st to 10thNight
15%36%17%28%31%
2160
11th to 20thNight
15%47%16%26%31%
2160
21st to endNight
18%48%21%24%25%
2376
November1st to 10thNight
28%7%10%22%17%16%
2351
11th to 20thNight
28%7%13%22%19%10%
2496
21st to endNight
30%5%7%22%22%13%
2660
December1st to 10thNight
36%5%11%18%18%12%
2660
11th to 20thNight
51%5%8%14%17%5%
3276
21st to endNight
47%8%11%17%12%4
4862

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
42%8%13%22%14%1
180
11th to 20thDay
24%9%18%28%14%6%
327
21st to endDay
23%5%20%23%22%7%
407
February1st to 10thDay
23%9%18%26%19%5%
370
11th to 20thDay
22%13%21%23%16%4
394
21st to endDay
16%12%25%27%16%3
382
March1st to 10thDay
26%16%25%20%10%2
449
11th to 20thDay
25%10%21%24%16%4
420
21st to endDay
21%15%24%26%13%2
462
April1st to 10thDay
18%15%24%25%15%4
420
11th to 20thDay
15%14%24%25%16%6%
412
21st to endDay
6%13%21%31%23%6%
420
May1st to 10thDay
8%8%32%26%21%5%
423
11th to 20thDay
8%9%22%25%23%12%
448
21st to endDay
5%9%19%26%31%11%
485
June1st to 10thDay
5%8%17%28%32%10%
450
11th to 20thDay
36%20%34%29%7%
450
21st to endDay
1414%35%33%13%
450
July1st to 10thDay
1210%36%40%10%
446
11th to 20thDay
18%32%44%14%
444
21st to endDay
15%34%45%15%
487
August1st to 10thDay
2112%29%40%15%
447
11th to 20thDay
118%27%43%20%
437
21st to endDay
119%29%46%13%
495
September1st to 10thDay
129%30%44%14%
450
11th to 20thDay
4317%28%34%14%
450
21st to endDay
35%19%34%29%10%
450
October1st to 10thDay
48%21%25%28%14%
450
11th to 20thDay
7%6%18%24%31%14%
450
21st to endDay
12%6%18%27%25%11%
495
November1st to 10thDay
16%7%17%23%25%12%
324
11th to 20thDay
14%5%14%30%25%12%
257
21st to endDay
12%6%19%29%27%7%
180
December1st to 10thDay
25%6%21%22%14%13%
180
11th to 20thDay
27%420%24%17%8%
180
21st to endDay
20%9%20%25%22%4
198
January1st to 10thNight
22%5%17%34%20%2
760
11th to 20thNight
22%5%14%39%18%2
760
21st to endNight
20%419%34%20%3
836
February1st to 10thNight
20%417%38%19%2
760
11th to 20thNight
18%7%18%33%21%2
744
21st to endNight
18%6%24%36%14%1
628
March1st to 10thNight
23%10%20%29%16%3
750
11th to 20thNight
20%7%19%30%23%2
720
21st to endNight
19%9%23%32%16%1
792
April1st to 10thNight
12%7%27%34%18%2
720
11th to 20thNight
12%7%24%33%21%4
711
21st to endNight
8%6%21%37%24%3
720
May1st to 10thNight
7%7%28%33%24%2
594
11th to 20thNight
5%323%38%28%2
354
21st to endNight
6%8%18%39%28%1
389
June1st to 10thNight
7%320%41%27%2
360
11th to 20thNight
1422%48%24%1
360
21st to endNight
2216%45%33%3
360
July1st to 10thNight
112%49%36%2
350
11th to 20thNight
112%51%34%2
348
21st to endNight
17%40%48%4
580
August1st to 10thNight
129%36%47%4
537
11th to 20thNight
8%41%46%5%
614
21st to endNight
15%39%52%3
792
September1st to 10thNight
218%37%49%4
720
11th to 20thNight
4210%38%39%8%
720
21st to endNight
4314%35%36%9%
720
October1st to 10thNight
6%418%34%33%6%
720
11th to 20thNight
7%314%34%36%5%
720
21st to endNight
9%414%35%30%8%
792
November1st to 10thNight
14%6%14%31%30%4
740
11th to 20thNight
14%218%39%25%2
760
21st to endNight
13%417%40%23%3
760
December1st to 10thNight
22%415%35%21%4
760
11th to 20thNight
28%416%30%20%2
760
21st to endNight
23%6%20%34%17%1
836
Page generated at 2024-03-05 04:23:58. Version ac07

Copyright © 2024 Attilla Danko.


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