Burwash
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Burwash clear sky chart from 2005-11-06 to 2024-12-24.

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
29%
24447
12%
98541
8%
24181
36%
24181
14%
67908

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
17%
942
7%
4722
4%
926
23%
926
7%
3606
January11th to 20thNight
18%
944
8%
4564
3%
930
24%
930
7%
3298
January21st to endNight
25%
875
8%
4599
7%
858
32%
858
7%
3671
February1st to 10thNight
17%
760
11%
2470
4%
760
25%
760
12%
1856
February11th to 20thNight
20%
740
13%
2403
5%
739
30%
739
13%
1782
February21st to endNight
19%
628
11%
1965
4%
628
27%
628
11%
1501
March1st to 10thNight
19%
759
20%
3491
6%
745
29%
745
12%
2275
March11th to 20thNight
22%
756
16%
3457
6%
740
31%
740
12%
2260
March21st to endNight
25%
833
11%
3738
6%
814
34%
814
14%
2414
April1st to 10thNight
24%
757
15%
1968
6%
757
29%
757
19%
1460
April11th to 20thNight
30%
563
19%
1687
9%
563
38%
563
21%
1154
April21st to endNight
29%
570
14%
1710
7%
570
35%
570
18%
1222
May1st to 10thNight
34%
564
18%
2775
10%
555
42%
555
14%
1718
May11th to 20thNight
37%
367
14%
2433
17%
364
50%
364
13%
1328
May21st to endNight
34%
407
11%
2627
11%
399
46%
399
14%
1468
June1st to 10thNight
35%
380
12%
1330
10%
380
42%
380
22%
847
June11th to 20thNight
41%
380
15%
1330
13%
380
48%
380
25%
802
June21st to endNight
39%
380
12%
1330
10%
380
46%
380
23%
825
July1st to 10thNight
50%
365
14%
2091
15%
360
57%
360
19%
1185
July11th to 20thNight
50%
365
13%
1916
16%
358
58%
358
19%
1089
July21st to endNight
49%
538
11%
2334
12%
504
53%
504
21%
1325
August1st to 10thNight
51%
556
15%
2550
11%
545
56%
545
19%
1573
August11th to 20thNight
50%
553
13%
2586
12%
543
57%
543
20%
1474
August21st to endNight
47%
611
15%
2820
11%
605
53%
605
19%
1611
September1st to 10thNight
45%
747
19%
1887
9%
747
49%
747
32%
1234
September11th to 20thNight
48%
760
20%
2076
13%
760
52%
760
36%
1258
September21st to endNight
41%
760
21%
2090
14%
760
46%
760
26%
1419
October1st to 10thNight
32%
760
13%
2798
12%
740
39%
740
15%
2028
October11th to 20thNight
25%
760
12%
2955
9%
740
34%
740
13%
2150
October21st to endNight
19%
836
7%
3902
6%
814
26%
814
8%
2810
November1st to 10thNight
26%
780
16%
2656
9%
780
36%
780
16%
1819
November11th to 20thNight
25%
800
12%
2800
8%
800
32%
800
12%
2045
November21st to endNight
19%
800
10%
2800
5%
800
25%
800
9%
2172
December1st to 10thNight
18%
800
9%
2800
3%
800
25%
800
9%
2184
December11th to 20thNight
17%
995
11%
3634
3%
993
25%
993
10%
2720
December21st to endNight
17%
1056
5%
5247
2%
1044
21%
1044
5%
4325

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
16%11%38%5%4445%6%33%
102008
Night
15%12%49%5%4445%6%32%
98161
TransparencyDay
50%5%12%22%10%1
105522
Night
51%5%12%21%10%1
102723
SeeingDay
22%15%32%20%8%3
15342
Night
22%12%30%27%9%1
24556

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
16%21%8%10%5%5%423422%
2208
11th to 20thDay
10%15%6%19%7%6%5%45%5%18%
2374
21st to endDay
18%22%8%10%5%5%443415%
3041
February1st to 10thDay
11%18%5%11%6%6%5%45%5%23%
1710
11th to 20thDay
12%17%6%9%7%44345%28%
1663
21st to endDay
14%19%6%12%6%44345%25%
1484
March1st to 10thDay
19%15%47%44435%6%28%
3330
11th to 20thDay
10%16%411%6%6%5%35%5%29%
3480
21st to endDay
12%15%5%10%5%44345%33%
3815
April1st to 10thDay
20%14%37%44435%6%30%
2227
11th to 20thDay
22%9%36%5%44345%34%
2442
21st to endDay
23%10%37%433246%35%
2470
May1st to 10thDay
19%8%36%5%5%5%35%6%34%
4126
11th to 20thDay
14%7%37%44446%6%41%
4398
21st to endDay
18%7%25%434346%43%
4923
June1st to 10thDay
17%8%38%6%445%7%7%33%
2850
11th to 20thDay
12%7%28%5%45%46%7%40%
2850
21st to endDay
17%8%37%5%5%5%46%7%33%
2850
July1st to 10thDay
15%8%38%5%5%5%46%8%34%
4760
11th to 20thDay
11%6%26%5%45%46%8%43%
4760
21st to endDay
11%6%25%44446%8%46%
4682
August1st to 10thDay
11%6%28%5%5%5%5%7%9%38%
4104
11th to 20thDay
18%6%25%44446%8%40%
4044
21st to endDay
11%6%37%5%5%446%7%42%
4512
September1st to 10thDay
15%7%36%5%4445%8%39%
2280
11th to 20thDay
14%5%26%5%4435%8%44%
2101
21st to endDay
21%8%36%5%4435%5%36%
2090
October1st to 10thDay
18%8%37%46%5%35%6%36%
1907
11th to 20thDay
24%12%48%45%445%6%25%
1900
21st to endDay
26%14%48%445%35%423%
1990
November1st to 10thDay
18%13%39%5%3436%6%29%
1642
11th to 20thDay
18%15%411%5%5%435%5%26%
1600
21st to endDay
23%20%410%6%4433418%
1600
December1st to 10thDay
14%21%6%12%6%4445%6%20%
1600
11th to 20thDay
17%19%5%10%5%45%35%5%23%
1743
21st to endDay
23%22%5%12%44433414%
2452
January1st to 10thNight
15%16%6%13%6%5%445%5%20%
4748
11th to 20thNight
12%15%6%11%6%5%6%5%6%6%22%
4592
21st to endNight
14%20%7%13%6%5%434419%
4615
February1st to 10thNight
12%16%5%12%7%45%5%5%6%25%
2470
11th to 20thNight
12%14%5%10%7%6%445%5%27%
2403
21st to endNight
14%15%5%11%6%6%5%45%5%25%
1965
March1st to 10thNight
16%13%38%5%4435%6%34%
3509
11th to 20thNight
11%14%5%10%5%4435%6%33%
3479
21st to endNight
13%10%48%6%6%445%5%36%
3817
April1st to 10thNight
20%12%47%5%4445%5%31%
1968
11th to 20thNight
20%9%36%5%34346%38%
1687
21st to endNight
20%8%39%5%4445%5%32%
1710
May1st to 10thNight
17%8%37%5%4446%5%38%
2815
11th to 20thNight
11%7%27%5%5%5%46%8%40%
2495
21st to endNight
12%8%38%5%4345%8%42%
2653
June1st to 10thNight
13%8%27%6%45%5%6%6%38%
1330
11th to 20thNight
14%6%25%45%5%5%6%8%42%
1330
21st to endNight
14%5%37%34437%8%42%
1330
July1st to 10thNight
13%6%36%44446%8%42%
2210
11th to 20thNight
12%426%43446%8%46%
2210
21st to endNight
9%5%26%43436%8%51%
2868
August1st to 10thNight
10%7%46%445%45%7%43%
2825
11th to 20thNight
14%6%26%33435%8%46%
2785
21st to endNight
12%7%26%34436%7%47%
3124
September1st to 10thNight
13%6%15%5%4445%6%47%
1887
11th to 20thNight
13%5%25%34435%7%49%
2076
21st to endNight
18%7%26%443347%41%
2090
October1st to 10thNight
20%8%36%5%4335%6%37%
2272
11th to 20thNight
24%11%46%5%3425%6%31%
2280
21st to endNight
24%12%39%5%44345%26%
2603
November1st to 10thNight
18%11%37%44436%6%34%
2656
11th to 20thNight
18%13%49%5%6%435%5%27%
2800
21st to endNight
22%16%39%5%445%5%5%22%
2800
December1st to 10thNight
17%17%5%11%6%5%4345%22%
2800
11th to 20thNight
18%16%49%6%4445%6%26%
3671
21st to endNight
23%22%5%14%44323416%
5288

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
67%5%12%12%3
2209
11th to 20thDay
68%412%11%41
2374
21st to endDay
72%48%10%6%
3041
February1st to 10thDay
62%411%16%6%1
1710
11th to 20thDay
58%410%16%11%1
1672
21st to endDay
63%47%17%9%1
1484
March1st to 10thDay
56%5%14%14%11%1
3333
11th to 20thDay
56%412%20%7%1
3480
21st to endDay
53%410%20%11%3
3815
April1st to 10thDay
54%413%18%10%1
2227
11th to 20thDay
51%48%24%12%1
2442
21st to endDay
52%39%19%15%3
2470
May1st to 10thDay
46%7%8%25%12%2
4138
11th to 20thDay
41%5%14%28%11%1
4402
21st to endDay
41%413%20%20%2
4923
June1st to 10thDay
47%6%12%21%13%1
2850
11th to 20thDay
42%5%11%24%17%1
2850
21st to endDay
48%6%12%21%11%2
2850
July1st to 10thDay
46%5%16%23%10%1
4686
11th to 20thDay
37%5%15%34%9%1
4679
21st to endDay
35%5%13%32%16%
4533
August1st to 10thDay
41%6%13%30%10%1
4091
11th to 20thDay
41%6%16%27%10%
4083
21st to endDay
39%5%13%33%10%1
4512
September1st to 10thDay
43%7%13%26%10%1
2280
11th to 20thDay
39%5%16%29%11%1
2101
21st to endDay
50%6%14%23%8%
2090
October1st to 10thDay
40%5%11%31%13%
3167
11th to 20thDay
48%5%14%25%8%
3140
21st to endDay
64%313%13%6%
3253
November1st to 10thDay
54%6%13%20%7%
1642
11th to 20thDay
60%5%11%17%7%
1600
21st to endDay
70%410%12%5%
1600
December1st to 10thDay
64%5%11%15%41
1600
11th to 20thDay
63%410%18%41
1743
21st to endDay
73%48%11%4
2452
January1st to 10thNight
64%6%12%12%6%
4748
11th to 20thNight
61%5%17%13%5%
4592
21st to endNight
69%48%13%6%
4615
February1st to 10thNight
59%6%11%18%6%1
2470
11th to 20thNight
58%5%12%18%8%1
2405
21st to endNight
60%5%10%15%9%1
1965
March1st to 10thNight
50%5%11%19%14%1
3519
11th to 20thNight
51%5%13%19%10%2
3480
21st to endNight
48%5%10%21%13%3
3817
April1st to 10thNight
54%49%20%12%2
1968
11th to 20thNight
49%36%24%16%2
1687
21st to endNight
54%49%16%16%2
1710
May1st to 10thNight
46%5%9%25%12%2
2822
11th to 20thNight
39%7%10%27%16%1
2496
21st to endNight
41%6%9%24%14%5%
2654
June1st to 10thNight
42%7%12%23%13%3
1330
11th to 20thNight
37%6%12%24%19%1
1330
21st to endNight
40%7%14%22%15%2
1330
July1st to 10thNight
39%5%14%26%14%2
2175
11th to 20thNight
35%6%16%32%11%1
2168
21st to endNight
33%413%30%20%
2777
August1st to 10thNight
39%5%15%26%13%1
2814
11th to 20thNight
37%420%29%9%1
2812
21st to endNight
37%414%31%13%1
3124
September1st to 10thNight
37%6%13%30%12%2
1887
11th to 20thNight
33%5%16%34%11%
2076
21st to endNight
43%6%13%27%10%
2090
October1st to 10thNight
40%410%32%14%
3792
11th to 20thNight
45%413%32%6%
3779
21st to endNight
54%5%19%16%6%
4277
November1st to 10thNight
50%6%14%23%8%
2656
11th to 20thNight
58%413%17%7%1
2800
21st to endNight
62%6%12%14%5%
2800
December1st to 10thNight
64%5%11%16%4
2800
11th to 20thNight
60%5%11%15%8%1
3670
21st to endNight
73%39%10%4
5288

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
24%21%31%16%8%1
180
11th to 20thDay
19%13%37%20%8%1
227
21st to endDay
26%14%34%17%8%1
297
February1st to 10thDay
26%22%34%12%4
270
11th to 20thDay
21%25%41%11%2
270
21st to endDay
31%26%34%9%
225
March1st to 10thDay
23%21%36%17%4
392
11th to 20thDay
21%19%36%18%5%1
460
21st to endDay
27%19%33%16%41
506
April1st to 10thDay
26%15%34%17%7%1
460
11th to 20thDay
33%21%20%16%7%3
452
21st to endDay
31%16%28%15%7%2
460
May1st to 10thDay
25%11%34%18%8%3
463
11th to 20thDay
22%16%31%18%10%4
487
21st to endDay
20%16%32%21%9%1
576
June1st to 10thDay
18%18%38%21%5%
680
11th to 20thDay
16%18%38%21%6%2
680
21st to endDay
21%14%35%21%8%1
680
July1st to 10thDay
11%14%37%27%10%2
671
11th to 20thDay
13%12%35%26%10%4
668
21st to endDay
14%9%32%29%12%5%
601
August1st to 10thDay
19%8%26%27%15%5%
486
11th to 20thDay
15%6%27%26%18%9%
479
21st to endDay
18%11%29%24%11%8%
539
September1st to 10thDay
19%12%29%22%12%6%
490
11th to 20thDay
14%8%28%30%13%7%
490
21st to endDay
24%12%28%20%14%3
490
October1st to 10thDay
21%17%26%22%11%2
490
11th to 20thDay
27%17%33%17%5%1
490
21st to endDay
36%17%29%15%21
439
November1st to 10thDay
29%17%37%13%4
240
11th to 20thDay
23%21%39%13%5%1
200
21st to endDay
35%17%30%13%6%1
200
December1st to 10thDay
24%16%33%21%7%
200
11th to 20thDay
28%21%36%12%4
200
21st to endDay
34%16%33%11%6%
204
January1st to 10thNight
23%15%32%23%6%1
950
11th to 20thNight
26%16%29%23%7%
950
21st to endNight
21%10%32%28%8%1
880
February1st to 10thNight
20%18%37%22%4
760
11th to 20thNight
21%15%35%23%5%1
743
21st to endNight
22%18%33%23%4
628
March1st to 10thNight
19%18%36%23%5%
760
11th to 20thNight
23%16%33%22%6%1
760
21st to endNight
20%14%35%24%7%1
836
April1st to 10thNight
26%15%29%25%4
757
11th to 20thNight
23%13%29%25%8%1
563
21st to endNight
23%12%27%28%9%
570
May1st to 10thNight
18%9%29%33%10%1
565
11th to 20thNight
16%9%31%34%10%
374
21st to endNight
14%9%36%32%10%
411
June1st to 10thNight
16%7%34%34%8%
380
11th to 20thNight
17%11%26%38%9%
380
21st to endNight
17%8%29%32%14%
380
July1st to 10thNight
9%6%29%46%8%1
370
11th to 20thNight
11%5%27%40%16%1
368
21st to endNight
10%5%27%38%19%2
552
August1st to 10thNight
12%424%39%18%2
567
11th to 20thNight
15%422%32%23%3
564
21st to endNight
16%7%22%32%21%1
627
September1st to 10thNight
16%7%27%30%19%1
747
11th to 20thNight
14%9%24%28%20%3
760
21st to endNight
21%7%25%28%17%3
760
October1st to 10thNight
24%11%27%25%12%1
760
11th to 20thNight
31%10%28%23%7%1
760
21st to endNight
30%14%29%22%41
836
November1st to 10thNight
26%12%29%24%7%1
780
11th to 20thNight
26%14%28%26%6%
800
21st to endNight
29%14%30%21%6%
800
December1st to 10thNight
28%15%31%21%5%1
800
11th to 20thNight
27%15%32%21%5%
995
21st to endNight
30%16%26%22%6%
1063
Page generated at 2024-12-21 04:13:50. Version ac07

Copyright © 2024 Attilla Danko.


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