Melfort
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Melfort clear sky chart from 2005-11-05 to 2017-04-07.

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
38%
15252
11%
45447
7%
15220
43%
15220
20%
32254

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 15thNight
31%
895
10%
2798
7%
895
35%
895
14%
2105
January16th to endNight
26%
960
11%
2769
6%
960
31%
960
14%
2153
February1st to 15thNight
39%
843
12%
2433
7%
843
43%
843
18%
1786
February16th to endNight
43%
632
12%
1998
10%
632
46%
632
16%
1466
March1st to 15thNight
37%
720
14%
2160
9%
720
41%
720
18%
1560
March16th to endNight
41%
651
16%
2006
12%
651
47%
651
19%
1413
April1st to 15thNight
43%
515
16%
1718
14%
515
49%
515
24%
1101
April16th to endNight
40%
495
13%
1372
9%
495
42%
495
24%
964
May1st to 15thNight
43%
494
10%
1320
6%
494
47%
494
27%
902
May16th to endNight
44%
454
3%
1167
2%
453
45%
453
25%
822
June1st to 15thNight
45%
330
0%
990
0%
330
45%
330
23%
676
June16th to endNight
48%
330
0%
990
0%
330
48%
330
24%
666
July1st to 15thNight
58%
310
0%
930
0%
310
58%
310
34%
544
July16th to endNight
57%
421
3%
1187
3%
393
57%
393
35%
687
August1st to 15thNight
60%
494
11%
1312
7%
491
62%
491
38%
787
August16th to endNight
54%
525
15%
1547
10%
525
58%
525
34%
909
September1st to 15thNight
54%
495
16%
1650
16%
495
56%
495
28%
971
September16th to endNight
45%
510
20%
1784
16%
510
54%
510
30%
1007
October1st to 15thNight
39%
663
16%
1983
9%
663
45%
663
22%
1354
October16th to endNight
33%
880
13%
2288
5%
880
38%
880
21%
1684
November1st to 15thNight
26%
875
13%
2459
6%
875
32%
875
17%
1881
November16th to endNight
30%
900
10%
2700
5%
900
36%
900
14%
2066
December1st to 15thNight
28%
900
6%
2814
3%
900
31%
900
9%
2327
December16th to endNight
29%
960
10%
3072
6%
960
35%
960
11%
2423

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%32%
45827
Night
11%10%48%6%35%5%5%7%31%
45591
Cloud CoverDay
14%9%37%6%35%5%5%7%32%
45828
Night
11%10%47%6%35%5%5%7%31%
45593
TransparencyDay
50%5%16%21%5%
45473
Night
51%415%21%6%
45449
SeeingDay
18%6%24%28%18%4
5468
Night
16%425%33%16%2
15267

By Month

Percentage Cloud Cover NW (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 15thDay
10%15%49%7%47%6%6%7%20%
1139
16th to endDay
10%11%5%9%8%46%46%6%25%
1455
February1st to 15thDay
7%9%410%7%5%9%7%7%8%21%
1438
16th to endDay
7%13%7%13%10%5%6%5%5%5%20%
1476
March1st to 15thDay
12%13%7%8%6%45%45%6%25%
1800
16th to endDay
11%13%49%7%45%35%6%28%
2216
April1st to 15thDay
9%11%5%6%5%245%5%7%35%
2045
16th to endDay
14%10%47%6%2435%8%31%
2258
May1st to 15thDay
11%7%36%5%45%6%6%8%35%
2301
16th to endDay
19%6%345%345%5%7%34%
2593
June1st to 15thDay
22%6%36%6%36%5%6%6%26%
2640
16th to endDay
20%6%26%5%36%5%5%8%29%
2640
July1st to 15thDay
13%5%25%425%5%6%9%39%
2640
16th to endDay
13%4245%25%5%5%8%40%
2580
August1st to 15thDay
12%424435%5%5%8%41%
2310
16th to endDay
14%42433436%7%44%
2301
September1st to 15thDay
13%5%345%35%5%5%7%41%
1980
16th to endDay
13%5%245%24347%45%
1844
October1st to 15thDay
17%12%35%5%23347%32%
1636
16th to endDay
16%13%46%5%2435%5%31%
1584
November1st to 15thDay
16%15%48%6%3345%5%27%
1396
16th to endDay
10%14%6%12%9%36%45%5%21%
1260
December1st to 15thDay
8%14%7%12%10%5%7%5%3417%
1143
16th to endDay
8%15%8%13%9%46%5%5%418%
1152
January1st to 15thNight
8%14%6%11%7%46%5%5%6%23%
2798
16th to endNight
8%13%5%9%8%46%7%5%7%21%
2769
February1st to 15thNight
7%10%48%8%5%6%5%6%8%27%
2424
16th to endNight
6%11%5%9%8%46%6%5%6%27%
1998
March1st to 15thNight
13%10%48%6%35%5%6%7%28%
2160
16th to endNight
8%10%48%8%45%5%6%8%29%
2003
April1st to 15thNight
10%9%27%5%2446%6%39%
1718
16th to endNight
18%7%35%5%34446%36%
1372
May1st to 15thNight
12%7%25%6%345%36%39%
1319
16th to endNight
18%5%37%435%5%47%36%
1167
June1st to 15thNight
16%7%25%5%2446%8%34%
990
16th to endNight
15%6%245%3446%9%35%
990
July1st to 15thNight
10%322426%5%6%9%46%
990
16th to endNight
9%42432345%7%51%
1276
August1st to 15thNight
9%31442346%9%49%
1320
16th to endNight
11%31342445%8%48%
1547
September1st to 15thNight
13%6%2342345%7%46%
1650
16th to endNight
14%42341345%7%48%
1784
October1st to 15thNight
14%11%35%5%3345%6%35%
1983
16th to endNight
14%12%36%5%35%5%5%6%32%
2288
November1st to 15thNight
15%14%6%8%6%2445%5%27%
2459
16th to endNight
9%13%5%9%8%46%45%6%25%
2700
December1st to 15thNight
9%12%6%13%11%5%6%6%46%16%
2814
16th to endNight
7%12%7%14%9%5%6%5%6%6%19%
3072

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 15thDay
10%14%5%9%7%5%7%7%6%7%19%
1139
16th to endDay
11%11%5%8%8%46%45%7%25%
1455
February1st to 15thDay
7%10%410%7%49%7%6%8%22%
1438
16th to endDay
7%13%7%13%9%5%6%5%6%5%19%
1476
March1st to 15thDay
12%12%7%8%7%35%5%47%25%
1800
16th to endDay
12%13%48%6%45%346%28%
2217
April1st to 15thDay
10%11%46%5%335%5%7%35%
2045
16th to endDay
15%10%37%5%2445%7%32%
2258
May1st to 15thDay
12%6%26%5%45%6%5%8%35%
2301
16th to endDay
19%6%25%5%3445%7%34%
2593
June1st to 15thDay
22%7%36%5%35%5%6%6%26%
2640
16th to endDay
21%5%35%5%36%5%5%7%29%
2640
July1st to 15thDay
13%5%24435%5%6%9%39%
2640
16th to endDay
14%4245%25%5%5%7%41%
2580
August1st to 15thDay
13%424436%46%8%42%
2310
16th to endDay
14%415%33335%7%44%
2301
September1st to 15thDay
13%5%25%5%25%5%5%7%41%
1980
16th to endDay
14%424433347%45%
1844
October1st to 15thDay
17%12%45%5%23348%31%
1636
16th to endDay
17%14%46%42435%431%
1584
November1st to 15thDay
16%14%48%6%24445%27%
1396
16th to endDay
10%13%7%12%9%36%45%5%21%
1260
December1st to 15thDay
9%14%6%13%10%5%7%5%3417%
1143
16th to endDay
8%13%9%14%9%36%5%5%418%
1152
January1st to 15thNight
9%13%7%10%7%36%5%5%6%23%
2798
16th to endNight
8%13%5%10%8%46%7%6%6%21%
2769
February1st to 15thNight
7%10%48%9%47%6%5%8%27%
2424
16th to endNight
6%11%6%9%8%47%6%46%27%
1998
March1st to 15thNight
12%10%48%6%45%5%6%7%28%
2160
16th to endNight
8%11%48%7%45%6%5%7%30%
2006
April1st to 15thNight
10%8%36%5%2446%6%39%
1718
16th to endNight
18%8%345%33446%36%
1372
May1st to 15thNight
14%7%35%6%44445%40%
1319
16th to endNight
18%5%36%5%25%35%7%36%
1166
June1st to 15thNight
16%7%246%2446%8%35%
990
16th to endNight
16%6%245%25%5%6%9%36%
990
July1st to 15thNight
11%323325%6%6%10%46%
990
16th to endNight
10%32442435%7%50%
1276
August1st to 15thNight
10%31342346%8%50%
1320
16th to endNight
12%31343346%8%48%
1547
September1st to 15thNight
14%6%24423448%45%
1650
16th to endNight
14%41342335%7%48%
1784
October1st to 15thNight
15%11%35%43445%6%35%
1983
16th to endNight
14%11%46%4346%46%32%
2288
November1st to 15thNight
15%14%6%8%5%24445%27%
2459
16th to endNight
9%14%5%9%8%46%447%25%
2700
December1st to 15thNight
9%12%6%13%11%5%6%5%46%16%
2814
16th to endNight
8%12%7%14%9%46%5%5%5%19%
3072

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 15thDay
60%6%10%18%3
1139
16th to endDay
57%5%12%17%5%
1455
February1st to 15thDay
57%418%15%4
1438
16th to endDay
65%410%15%5%
1476
March1st to 15thDay
59%313%18%4
1800
16th to endDay
56%410%21%6%
2217
April1st to 15thDay
46%416%22%7%1
2045
16th to endDay
51%315%21%6%1
2258
May1st to 15thDay
45%5%12%24%10%1
2301
16th to endDay
48%5%14%19%11%
2597
June1st to 15thDay
55%5%12%19%5%
2640
16th to endDay
51%7%17%19%4
2640
July1st to 15thDay
40%6%22%25%4
2471
16th to endDay
41%6%26%22%3
2406
August1st to 15thDay
38%5%27%24%3
2294
16th to endDay
38%421%29%5%
2301
September1st to 15thDay
40%5%20%24%7%
1980
16th to endDay
38%5%17%26%10%1
1844
October1st to 15thDay
52%5%14%24%4
1636
16th to endDay
54%418%19%2
1584
November1st to 15thDay
58%413%17%5%
1396
16th to endDay
64%415%12%2
1260
December1st to 15thDay
69%412%11%
1143
16th to endDay
67%311%14%2
1152
January1st to 15thNight
59%412%18%5%
2798
16th to endNight
58%6%12%15%5%
2769
February1st to 15thNight
54%414%19%6%
2435
16th to endNight
56%411%20%7%
1998
March1st to 15thNight
52%5%14%22%5%
2160
16th to endNight
51%5%12%22%8%
2006
April1st to 15thNight
44%314%23%11%2
1718
16th to endNight
49%313%20%10%2
1372
May1st to 15thNight
45%39%23%16%1
1320
16th to endNight
47%413%19%13%1
1167
June1st to 15thNight
45%6%16%23%7%
990
16th to endNight
43%6%23%17%7%
990
July1st to 15thNight
31%6%20%32%8%
930
16th to endNight
32%428%28%5%
1187
August1st to 15thNight
30%6%25%32%5%
1312
16th to endNight
32%5%21%30%9%
1547
September1st to 15thNight
38%317%30%9%1
1650
16th to endNight
34%417%30%12%
1784
October1st to 15thNight
48%414%27%5%
1983
16th to endNight
51%5%17%20%5%
2288
November1st to 15thNight
58%412%18%5%1
2459
16th to endNight
59%5%16%15%3
2700
December1st to 15thNight
68%6%12%11%1
2814
16th to endNight
64%411%14%4
3072

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 15thDay
11%128%28%25%5%
60
16th to endDay
18%6%31%28%15%
83
February1st to 15thDay
11%426%44%13%
90
16th to endDay
23%323%32%11%6%
81
March1st to 15thDay
20%5%30%32%10%2
90
16th to endDay
19%7%29%26%14%2
276
April1st to 15thDay
12%10%32%29%12%2
234
16th to endDay
17%7%21%32%17%2
364
May1st to 15thDay
13%9%25%31%16%3
393
16th to endDay
19%422%23%22%8%
437
June1st to 15thDay
20%7%25%26%15%4
420
16th to endDay
22%6%21%24%17%6%
420
July1st to 15thDay
19%6%17%28%22%7%
400
16th to endDay
13%422%31%20%6%
445
August1st to 15thDay
15%417%26%30%5%
418
16th to endDay
14%421%33%19%7%
363
September1st to 15thDay
20%5%27%27%16%2
255
16th to endDay
15%7%25%39%10%2
138
October1st to 15thDay
36%424%17%12%4
90
16th to endDay
30%5%25%25%11%3
96
November1st to 15thDay
23%7%36%25%5%1
90
16th to endDay
26%7%24%16%20%4
90
December1st to 15thDay
16%428%23%18%8%
71
16th to endDay
10%431%28%17%7%
64
January1st to 15thNight
15%6%27%33%15%1
900
16th to endNight
14%6%36%32%8%
960
February1st to 15thNight
12%326%36%16%3
851
16th to endNight
10%322%38%20%4
632
March1st to 15thNight
18%5%25%33%14%2
720
16th to endNight
13%428%33%17%3
651
April1st to 15thNight
14%5%27%34%15%2
515
16th to endNight
22%5%22%33%13%2
495
May1st to 15thNight
16%425%37%14%2
495
16th to endNight
20%6%21%32%18%
455
June1st to 15thNight
20%420%34%18%1
330
16th to endNight
18%5%17%36%19%2
330
July1st to 15thNight
13%219%39%23%
310
16th to endNight
12%220%33%28%3
421
August1st to 15thNight
10%219%33%28%5%
494
16th to endNight
13%222%37%20%3
525
September1st to 15thNight
18%216%37%21%3
495
16th to endNight
16%329%37%12%1
510
October1st to 15thNight
20%425%33%14%2
663
16th to endNight
21%5%27%32%12%1
880
November1st to 15thNight
22%5%29%29%10%2
875
16th to endNight
17%7%30%33%10%1
900
December1st to 15thNight
16%426%32%16%4
900
16th to endNight
12%5%26%30%21%4
960
Page generated at 2017-04-08 03:35:16. Version ac04

Copyright 2017 A. Danko


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