Morrisburg
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Morrisburg clear sky chart from 2005-11-06 to 2024-01-31.

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
27%
22689
8%
74992
5%
22646
32%
22646
8%
61373

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
13%
760
4%
2649
2%
757
16%
757
3%
2361
January11th to 20thNight
17%
760
4%
2660
2%
760
18%
760
3%
2384
January21st to endNight
19%
835
6%
2862
4%
835
23%
835
6%
2439
February1st to 10thNight
14%
720
6%
2340
2%
720
19%
720
5%
2024
February11th to 20thNight
16%
703
8%
2235
3%
700
24%
700
6%
1893
February21st to endNight
19%
592
9%
1776
3%
592
27%
592
7%
1519
March1st to 10thNight
20%
720
9%
2160
5%
720
25%
720
7%
1832
March11th to 20thNight
19%
720
9%
2011
2%
720
25%
720
8%
1684
March21st to endNight
27%
792
13%
2039
5%
792
33%
792
11%
1665
April1st to 10thNight
22%
720
10%
1800
3%
720
25%
720
11%
1503
April11th to 20thNight
24%
711
11%
1775
3%
711
28%
711
13%
1456
April21st to endNight
25%
642
11%
1722
4%
642
29%
642
12%
1397
May1st to 10thNight
31%
360
10%
1440
6%
360
37%
360
8%
1104
May11th to 20thNight
31%
354
15%
1416
10%
354
42%
354
11%
1050
May21st to endNight
33%
389
11%
1551
8%
388
42%
388
12%
1121
June1st to 10thNight
36%
360
7%
1440
6%
360
43%
360
9%
1132
June11th to 20thNight
38%
360
10%
1440
12%
360
44%
360
10%
1055
June21st to endNight
38%
360
8%
1440
11%
360
42%
360
9%
1116
July1st to 10thNight
48%
350
8%
1400
11%
350
52%
350
12%
1007
July11th to 20thNight
48%
348
11%
1392
13%
348
54%
348
12%
1009
July21st to endNight
50%
394
10%
1486
8%
372
55%
372
11%
1093
August1st to 10thNight
52%
369
10%
1433
9%
367
57%
367
12%
1055
August11th to 20thNight
50%
578
13%
1642
8%
578
53%
578
18%
1246
August21st to endNight
43%
792
10%
1980
3%
792
46%
792
17%
1559
September1st to 10thNight
45%
720
9%
1800
3%
720
48%
720
15%
1442
September11th to 20thNight
49%
720
14%
1822
7%
720
52%
720
19%
1375
September21st to endNight
41%
720
12%
1998
9%
720
42%
720
14%
1585
October1st to 10thNight
33%
720
10%
2160
7%
720
37%
720
10%
1763
October11th to 20thNight
26%
720
10%
2160
5%
720
32%
720
9%
1781
October21st to endNight
23%
792
7%
2539
4%
792
28%
792
8%
2118
November1st to 10thNight
23%
740
9%
2407
6%
740
28%
740
8%
1937
November11th to 20thNight
22%
760
11%
2598
8%
760
28%
760
8%
2108
November21st to endNight
18%
760
7%
2660
4%
760
22%
760
5%
2273
December1st to 10thNight
15%
760
3%
2660
1%
760
17%
760
3%
2386
December11th to 20thNight
14%
760
7%
3251
3%
759
18%
759
4%
2731
December21st to endNight
13%
828
3%
4848
1%
817
16%
817
2%
4170

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
19%10%37%6%35%45%6%33%
74889
Night
19%11%47%6%3445%6%31%
75237
TransparencyDay
36%35%7%14%6%1
74594
Night
39%35%7%13%6%1
75066
SeeingDay
23%16%30%20%9%3
13466
Night
24%13%30%24%8%1
22697

By Month

Percentage Cloud Cover NE (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
20%20%7%9%7%35%34419%
1517
11th to 20thDay
19%17%7%9%8%345%4421%
1520
21st to endDay
13%16%5%10%8%5%5%45%5%22%
1720
February1st to 10thDay
18%15%7%10%8%45%45%5%21%
1620
11th to 20thDay
17%15%6%10%6%44435%26%
1613
21st to endDay
20%16%49%8%3444422%
1480
March1st to 10thDay
16%14%5%8%7%3434429%
1797
11th to 20thDay
19%12%48%7%44345%31%
1946
21st to endDay
21%11%35%5%33345%37%
2317
April1st to 10thDay
22%12%46%6%3434433%
2160
11th to 20thDay
22%9%46%5%34335%37%
2134
21st to endDay
24%10%36%4345%5%5%32%
2251
May1st to 10thDay
20%8%36%5%345%5%7%35%
2520
11th to 20thDay
16%7%36%6%25%45%6%40%
2478
21st to endDay
16%6%26%5%35%5%5%8%38%
2725
June1st to 10thDay
23%7%35%6%35%5%6%7%30%
2520
11th to 20thDay
16%6%35%5%45%5%6%7%39%
2520
21st to endDay
20%7%35%6%45%5%5%7%33%
2520
July1st to 10thDay
13%5%36%5%345%6%8%43%
2520
11th to 20thDay
14%5%25%5%36%6%7%9%38%
2520
21st to endDay
12%5%25%5%46%6%7%9%38%
2744
August1st to 10thDay
13%6%25%6%45%7%6%8%38%
2492
11th to 20thDay
13%6%25%6%45%5%6%8%41%
2241
21st to endDay
14%5%26%6%36%5%5%8%40%
2376
September1st to 10thDay
15%425%5%345%6%8%42%
2160
11th to 20thDay
16%42443445%7%46%
2138
21st to endDay
18%6%35%5%345%5%8%39%
1958
October1st to 10thDay
22%7%36%5%3445%7%34%
1800
11th to 20thDay
22%10%37%7%46%45%7%27%
1800
21st to endDay
28%10%37%5%45%336%26%
1816
November1st to 10thDay
17%9%47%6%35%45%7%32%
1671
11th to 20thDay
18%12%37%7%35%45%6%30%
1577
21st to endDay
22%14%5%8%7%35%446%21%
1520
December1st to 10thDay
25%17%5%9%6%44446%15%
1520
11th to 20thDay
22%18%5%8%6%24445%23%
1906
21st to endDay
27%17%410%6%3443320%
2772
January1st to 10thNight
20%18%6%10%8%34445%18%
2649
11th to 20thNight
18%18%6%10%7%35%44419%
2660
21st to endNight
15%16%6%10%7%44345%25%
2862
February1st to 10thNight
18%15%6%13%7%5%5%445%19%
2340
11th to 20thNight
15%13%6%10%7%35%35%5%27%
2233
21st to endNight
18%13%5%9%6%4444429%
1776
March1st to 10thNight
18%14%5%9%6%35%43429%
2150
11th to 20thNight
20%12%5%6%6%34445%32%
2011
21st to endNight
19%10%46%6%3434438%
2039
April1st to 10thNight
23%9%48%5%3434432%
1800
11th to 20thNight
21%9%36%5%3435%7%34%
1775
21st to endNight
23%9%37%434446%34%
1722
May1st to 10thNight
23%7%35%5%3445%6%35%
1440
11th to 20thNight
16%9%36%5%3445%6%40%
1415
21st to endNight
14%5%35%4345%6%8%43%
1550
June1st to 10thNight
20%5%36%5%5%6%5%7%8%30%
1440
11th to 20thNight
17%5%25%6%35%46%7%40%
1440
21st to endNight
19%7%25%5%35%5%6%8%35%
1440
July1st to 10thNight
11%325%5%35%5%6%9%45%
1440
11th to 20thNight
13%5%245%346%8%9%42%
1440
21st to endNight
12%425%435%6%7%8%43%
1574
August1st to 10thNight
12%7%25%5%445%6%9%42%
1443
11th to 20thNight
14%5%36%5%35%45%7%43%
1642
21st to endNight
14%5%25%5%345%6%7%44%
1980
September1st to 10thNight
16%6%25%5%35%5%5%5%44%
1800
11th to 20thNight
16%42342345%8%48%
1822
21st to endNight
16%6%35%6%345%5%6%42%
1998
October1st to 10thNight
20%7%36%5%345%5%7%34%
2160
11th to 20thNight
21%9%37%5%3445%6%33%
2160
21st to endNight
27%9%37%6%3445%6%27%
2539
November1st to 10thNight
20%11%36%5%345%45%35%
2407
11th to 20thNight
19%11%48%5%345%45%32%
2598
21st to endNight
23%13%5%8%6%34445%25%
2660
December1st to 10thNight
23%17%6%9%7%35%45%5%16%
2660
11th to 20thNight
23%16%5%9%5%3433425%
3288
21st to endNight
32%15%5%9%5%3433318%
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
46%38%7%7%2
1518
11th to 20thDay
46%38%5%6%5%1
1520
21st to endDay
45%34%7%8%41
1720
February1st to 10thDay
45%34%413%31
1620
11th to 20thDay
43%36%7%9%41
1622
21st to endDay
45%34%8%9%4
1480
March1st to 10thDay
41%34%8%12%5%
1800
11th to 20thDay
40%35%9%11%5%1
1946
21st to endDay
34%34%5%13%9%3
2317
April1st to 10thDay
38%34%415%8%2
2160
11th to 20thDay
36%34%414%11%2
2134
21st to endDay
37%35%5%10%10%3
2251
May1st to 10thDay
33%35%6%12%11%2
2520
11th to 20thDay
32%36%415%10%2
2482
21st to endDay
29%36%9%14%11%2
2725
June1st to 10thDay
37%36%8%12%7%
2520
11th to 20thDay
31%35%7%18%8%1
2520
21st to endDay
36%36%9%12%6%
2520
July1st to 10thDay
28%37%8%21%7%
2450
11th to 20thDay
29%36%10%17%6%
2445
21st to endDay
27%38%11%17%7%
2591
August1st to 10thDay
32%36%9%18%6%
2478
11th to 20thDay
26%34%12%20%7%
2241
21st to endDay
29%36%8%19%8%
2376
September1st to 10thDay
29%35%8%20%8%
2160
11th to 20thDay
29%35%6%22%8%
2138
21st to endDay
33%36%7%19%5%
1958
October1st to 10thDay
36%35%7%16%7%
1800
11th to 20thDay
42%35%8%11%4
1800
21st to endDay
41%36%7%10%6%
1816
November1st to 10thDay
30%39%9%16%5%
1671
11th to 20thDay
38%39%8%8%7%1
1577
21st to endDay
43%39%7%9%2
1520
December1st to 10thDay
48%39%6%6%1
1520
11th to 20thDay
48%31%10%10%1
1906
21st to endDay
59%24%5%12%1
2772
January1st to 10thNight
47%38%6%6%2
2649
11th to 20thNight
47%38%46%4
2660
21st to endNight
45%34%6%9%5%1
2862
February1st to 10thNight
46%34%6%9%4
2340
11th to 20thNight
42%36%6%12%3
2235
21st to endNight
43%35%6%10%5%1
1776
March1st to 10thNight
43%34%6%11%5%
2160
11th to 20thNight
40%35%8%12%41
2012
21st to endNight
35%35%5%13%10%2
2039
April1st to 10thNight
38%35%5%14%7%1
1800
11th to 20thNight
35%35%6%14%9%1
1775
21st to endNight
36%34%5%13%9%3
1722
May1st to 10thNight
34%35%5%10%12%4
1440
11th to 20thNight
30%36%416%11%3
1416
21st to endNight
27%36%10%14%11%2
1551
June1st to 10thNight
35%36%9%13%7%
1440
11th to 20thNight
29%36%10%15%9%1
1440
21st to endNight
34%35%9%12%9%
1440
July1st to 10thNight
26%37%9%19%9%1
1400
11th to 20thNight
26%37%9%18%9%
1392
21st to endNight
27%37%10%16%9%
1486
August1st to 10thNight
28%35%11%17%8%
1433
11th to 20thNight
27%35%9%18%11%1
1642
21st to endNight
29%36%10%18%7%1
1980
September1st to 10thNight
31%35%6%18%9%
1800
11th to 20thNight
26%35%10%22%7%
1822
21st to endNight
32%35%6%19%7%1
1998
October1st to 10thNight
37%36%6%14%7%
2160
11th to 20thNight
39%35%8%12%6%
2160
21st to endNight
39%36%10%9%5%1
2539
November1st to 10thNight
33%39%7%14%6%1
2407
11th to 20thNight
34%39%8%11%6%2
2598
21st to endNight
41%39%8%10%3
2660
December1st to 10thNight
47%38%6%7%1
2660
11th to 20thNight
48%31%7%11%3
3288
21st to endNight
60%23%6%10%1
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
32%19%27%18%4
180
11th to 20thDay
31%23%29%12%5%1
180
21st to endDay
25%18%34%18%5%
222
February1st to 10thDay
35%30%29%5%1
240
11th to 20thDay
27%26%37%9%1
280
21st to endDay
33%20%32%14%2
346
March1st to 10thDay
25%21%32%17%4
420
11th to 20thDay
26%21%35%14%31
420
21st to endDay
32%18%27%15%6%1
462
April1st to 10thDay
30%19%30%16%41
420
11th to 20thDay
29%22%22%18%6%2
412
21st to endDay
30%18%31%13%7%1
420
May1st to 10thDay
24%18%33%15%8%1
423
11th to 20thDay
18%19%34%17%9%2
447
21st to endDay
17%17%32%23%10%1
485
June1st to 10thDay
27%13%28%23%7%2
450
11th to 20thDay
16%15%33%25%8%3
450
21st to endDay
22%14%32%19%12%1
450
July1st to 10thDay
13%9%31%30%14%3
445
11th to 20thDay
14%10%31%30%12%3
444
21st to endDay
16%7%33%31%12%2
488
August1st to 10thDay
16%10%24%33%13%3
446
11th to 20thDay
14%7%27%28%16%8%
439
21st to endDay
14%10%33%23%14%7%
495
September1st to 10thDay
14%12%28%26%12%9%
450
11th to 20thDay
13%9%26%26%16%11%
450
21st to endDay
19%12%30%20%14%5%
450
October1st to 10thDay
24%15%26%17%13%5%
450
11th to 20thDay
25%19%30%17%7%2
450
21st to endDay
32%18%25%21%5%
412
November1st to 10thDay
24%21%28%18%8%1
365
11th to 20thDay
27%19%33%14%5%1
237
21st to endDay
27%23%33%12%41
180
December1st to 10thDay
29%23%27%16%41
180
11th to 20thDay
31%32%24%11%21
180
21st to endDay
33%24%26%13%41
198
January1st to 10thNight
29%19%30%19%3
760
11th to 20thNight
31%16%29%19%4
760
21st to endNight
22%16%34%25%4
835
February1st to 10thNight
25%19%35%20%2
720
11th to 20thNight
24%18%36%18%3
703
21st to endNight
26%18%31%23%2
592
March1st to 10thNight
26%15%33%23%3
720
11th to 20thNight
27%19%31%19%4
720
21st to endNight
25%15%27%26%7%
792
April1st to 10thNight
28%14%30%23%4
720
11th to 20thNight
25%18%30%20%7%
711
21st to endNight
28%13%30%21%7%1
642
May1st to 10thNight
26%9%29%27%8%2
360
11th to 20thNight
20%10%35%27%8%
354
21st to endNight
15%9%39%25%12%1
389
June1st to 10thNight
21%8%30%35%6%1
360
11th to 20thNight
18%11%28%29%13%1
360
21st to endNight
20%7%29%31%13%1
360
July1st to 10thNight
9%6%31%40%13%1
350
11th to 20thNight
15%427%37%17%1
348
21st to endNight
11%430%44%9%1
394
August1st to 10thNight
17%421%42%17%1
369
11th to 20thNight
14%5%21%38%20%1
578
21st to endNight
15%5%30%31%17%2
792
September1st to 10thNight
16%8%27%33%16%1
720
11th to 20thNight
18%7%22%31%19%3
720
21st to endNight
17%9%28%24%20%2
720
October1st to 10thNight
24%10%28%22%14%1
720
11th to 20thNight
25%13%30%23%8%
720
21st to endNight
31%14%28%23%5%
792
November1st to 10thNight
26%16%29%21%7%1
740
11th to 20thNight
24%20%29%19%8%
760
21st to endNight
29%18%28%19%6%
760
December1st to 10thNight
31%18%29%18%3
760
11th to 20thNight
29%19%33%15%41
760
21st to endNight
35%15%30%17%3
836
Page generated at 2024-01-28 05:26:35. Version ac07

Copyright 2024 Attilla Danko


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