Carnation
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Carnation clear sky chart from 2005-11-05 to 2017-12-20.

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
39%
14878
9%
47766
9%
14850
40%
14850
14%
36347

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
29%
725
9%
2538
9%
721
32%
721
9%
2038
January16th to endNight
35%
768
10%
2669
10%
768
35%
768
11%
2066
February1st to 15thNight
28%
698
5%
2288
4%
698
30%
698
9%
1893
February16th to endNight
31%
632
9%
2002
9%
632
34%
632
11%
1604
March1st to 15thNight
27%
720
5%
2084
4%
720
28%
720
9%
1736
March16th to endNight
25%
768
4%
2055
2%
768
26%
768
9%
1766
April1st to 15thNight
31%
719
5%
1799
3%
719
31%
719
11%
1536
April16th to endNight
36%
558
6%
1638
5%
558
36%
558
12%
1317
May1st to 15thNight
47%
359
10%
1439
16%
359
48%
359
15%
981
May16th to endNight
41%
374
4%
1496
7%
374
42%
374
9%
1154
June1st to 15thNight
39%
360
3%
1375
4%
360
39%
360
10%
1060
June16th to endNight
48%
360
6%
1260
7%
360
48%
360
15%
915
July1st to 15thNight
67%
340
11%
1227
15%
340
67%
340
28%
698
July16th to endNight
69%
376
16%
1416
28%
354
70%
354
30%
734
August1st to 15thNight
75%
431
19%
1503
24%
429
75%
429
35%
797
August16th to endNight
67%
654
20%
1800
17%
654
68%
654
38%
1077
September1st to 15thNight
70%
720
20%
1800
12%
720
70%
720
40%
1119
September16th to endNight
52%
716
17%
1965
15%
716
52%
716
23%
1404
October1st to 15thNight
49%
720
10%
2160
11%
720
50%
720
19%
1556
October16th to endNight
36%
768
9%
2388
9%
768
37%
768
12%
1875
November1st to 15thNight
24%
760
4%
2621
4%
760
25%
760
7%
2203
November16th to endNight
27%
780
5%
2730
5%
780
28%
780
8%
2245
December1st to 15thNight
34%
780
8%
2730
9%
780
35%
780
11%
2146
December16th to endNight
16%
792
4%
2783
4%
792
18%
792
5%
2427

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
26%8%36%5%24445%28%
49081
Night
27%8%35%5%24345%29%
47927
Cloud CoverDay
31%8%25%423335%27%
49081
Night
32%8%25%423335%28%
47931
TransparencyDay
60%5%12%14%6%1
48745
Night
59%5%12%14%6%1
47767
SeeingDay
31%6%20%25%12%3
6143
Night
34%5%12%25%19%3
14886

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
39%8%36%43332420%
1389
16th to endDay
33%9%45%423245%22%
1554
February1st to 15thDay
32%9%37%7%3444417%
1576
16th to endDay
30%12%5%6%5%2433321%
1471
March1st to 15thDay
38%12%46%5%2433414%
1875
16th to endDay
34%14%46%6%3444411%
2169
April1st to 15thDay
27%12%49%7%35%445%14%
2149
16th to endDay
26%11%49%6%35%445%17%
2322
May1st to 15thDay
23%8%46%6%34446%28%
2511
16th to endDay
30%8%35%6%34445%21%
2615
June1st to 15thDay
28%9%36%5%25%445%22%
2581
16th to endDay
21%7%37%6%35%5%5%5%28%
2700
July1st to 15thDay
11%425%423445%51%
2658
16th to endDay
14%5%1431335%5%51%
2657
August1st to 15thDay
12%423323347%51%
2448
16th to endDay
14%5%24434336%47%
2402
September1st to 15thDay
12%5%24322336%52%
2160
16th to endDay
22%8%25%423345%35%
1994
October1st to 15thDay
22%8%36%5%245%5%6%29%
1800
16th to endDay
36%7%26%424346%21%
1836
November1st to 15thDay
45%7%3443343315%
1567
16th to endDay
40%9%36%5%2433317%
1560
December1st to 15thDay
30%10%47%5%3434420%
1560
16th to endDay
38%12%46%6%2333316%
1527
January1st to 15thNight
39%8%34412335%21%
2538
16th to endNight
35%7%24423336%24%
2669
February1st to 15thNight
31%9%5%6%434336%19%
2276
16th to endNight
31%11%35%414435%23%
2002
March1st to 15thNight
35%9%45%424445%19%
2084
16th to endNight
32%9%37%5%35%45%5%16%
2051
April1st to 15thNight
25%10%47%7%35%5%5%5%18%
1799
16th to endNight
26%8%46%5%36%35%7%22%
1638
May1st to 15thNight
20%8%35%424447%34%
1439
16th to endNight
22%9%36%6%35%46%6%25%
1496
June1st to 15thNight
23%8%48%6%25%445%26%
1375
16th to endNight
18%8%47%6%3444334%
1260
July1st to 15thNight
8%4245%24345%55%
1300
16th to endNight
10%5%23313236%57%
1512
August1st to 15thNight
7%313322348%58%
1511
16th to endNight
10%5%14322335%57%
1800
September1st to 15thNight
9%5%14313345%57%
1800
16th to endNight
20%7%25%424445%39%
1965
October1st to 15thNight
22%6%35%5%23445%35%
2160
16th to endNight
32%9%15%5%23345%24%
2388
November1st to 15thNight
38%8%35%5%34345%17%
2621
16th to endNight
36%9%35%5%2433420%
2730
December1st to 15thNight
30%9%45%5%23445%24%
2730
16th to endNight
38%13%37%5%2323314%
2783

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
42%9%2432232321%
1389
16th to endDay
40%9%2432333422%
1554
February1st to 15thDay
34%11%37%6%23435%16%
1576
16th to endDay
33%14%46%42333321%
1471
March1st to 15thDay
44%12%35%42322413%
1875
16th to endDay
40%13%47%5%3443310%
2169
April1st to 15thDay
34%13%46%5%35%335%13%
2149
16th to endDay
32%12%38%6%3433316%
2322
May1st to 15thDay
29%8%345%34345%26%
2511
16th to endDay
34%8%37%5%34335%20%
2615
June1st to 15thDay
36%8%26%5%34335%20%
2581
16th to endDay
26%8%36%5%3445%5%27%
2700
July1st to 15thDay
15%5%245%13335%49%
2658
16th to endDay
17%5%13324345%48%
2657
August1st to 15thDay
16%413323347%49%
2448
16th to endDay
17%5%245%24446%44%
2402
September1st to 15thDay
15%6%24312335%51%
2160
16th to endDay
29%4245%23336%34%
1994
October1st to 15thDay
27%7%35%42345%5%29%
1800
16th to endDay
41%6%24423335%22%
1836
November1st to 15thDay
50%8%2343342213%
1567
16th to endDay
46%9%25%42222317%
1560
December1st to 15thDay
34%11%25%5%2334420%
1560
16th to endDay
41%15%45%5%2222215%
1527
January1st to 15thNight
43%9%1331323421%
2538
16th to endNight
39%7%24323325%24%
2669
February1st to 15thNight
35%10%35%424345%19%
2276
16th to endNight
35%12%2442323423%
2002
March1st to 15thNight
39%10%24423335%18%
2084
16th to endNight
37%11%35%6%34345%14%
2055
April1st to 15thNight
31%11%37%6%3445%6%16%
1799
16th to endNight
32%9%37%424446%20%
1638
May1st to 15thNight
25%6%35%423445%33%
1439
16th to endNight
29%8%36%4345%45%24%
1496
June1st to 15thNight
32%6%36%5%34435%24%
1375
16th to endNight
22%7%37%6%34335%32%
1260
July1st to 15thNight
12%42432333455%
1300
16th to endNight
12%423313336%54%
1512
August1st to 15thNight
9%412412246%59%
1511
16th to endNight
14%414312245%55%
1800
September1st to 15thNight
13%32342224456%
1800
16th to endNight
24%5%25%423335%38%
1965
October1st to 15thNight
27%5%25%433435%34%
2160
16th to endNight
37%7%24433345%23%
2388
November1st to 15thNight
45%7%25%42334315%
2621
16th to endNight
42%8%35%42333419%
2730
December1st to 15thNight
34%10%34323345%23%
2730
16th to endNight
44%14%25%5%2222313%
2783

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
69%47%10%6%1
1389
16th to endDay
66%310%10%6%2
1554
February1st to 15thDay
70%6%9%8%31
1576
16th to endDay
69%38%12%4
1471
March1st to 15thDay
76%310%8%1
1875
16th to endDay
79%48%7%
2169
April1st to 15thDay
73%7%10%7%
2149
16th to endDay
71%5%11%8%2
2322
May1st to 15thDay
58%5%15%15%4
2511
16th to endDay
66%6%13%11%1
2619
June1st to 15thDay
67%5%14%8%3
2581
16th to endDay
58%6%15%14%4
2700
July1st to 15thDay
38%5%13%26%14%1
2502
16th to endDay
35%5%12%28%14%2
2490
August1st to 15thDay
36%416%27%12%2
2431
16th to endDay
40%416%27%8%2
2402
September1st to 15thDay
35%413%23%18%3
2160
16th to endDay
52%5%14%15%8%2
1994
October1st to 15thDay
55%6%12%17%6%
1800
16th to endDay
65%5%9%12%7%
1836
November1st to 15thDay
74%5%9%6%21
1567
16th to endDay
73%46%8%5%1
1560
December1st to 15thDay
67%6%6%12%6%
1560
16th to endDay
76%36%7%4
1527
January1st to 15thNight
67%48%10%6%1
2538
16th to endNight
63%5%9%9%8%3
2669
February1st to 15thNight
68%6%10%8%41
2288
16th to endNight
65%410%13%5%
2002
March1st to 15thNight
69%5%12%11%2
2084
16th to endNight
71%5%12%9%
2055
April1st to 15thNight
67%7%11%11%1
1799
16th to endNight
64%6%14%11%2
1638
May1st to 15thNight
52%417%17%7%
1440
16th to endNight
61%7%17%10%2
1496
June1st to 15thNight
63%5%14%11%4
1375
16th to endNight
55%6%15%18%31
1260
July1st to 15thNight
34%5%13%28%14%3
1227
16th to endNight
31%414%29%17%3
1416
August1st to 15thNight
28%6%15%32%14%3
1503
16th to endNight
32%419%30%10%2
1800
September1st to 15thNight
31%5%14%23%20%4
1800
16th to endNight
48%5%13%17%11%2
1965
October1st to 15thNight
52%5%13%18%7%1
2160
16th to endNight
62%5%11%12%7%
2388
November1st to 15thNight
72%411%7%12
2621
16th to endNight
70%48%8%7%
2730
December1st to 15thNight
64%5%10%11%6%1
2730
16th to endNight
77%47%6%3
2783

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
20%111%26%28%11%
60
16th to endDay
59%7%6%10%13%2
82
February1st to 15thDay
46%6%16%20%9%
236
16th to endDay
41%8%22%20%6%
220
March1st to 15thDay
54%13%18%10%2
270
16th to endDay
51%11%19%11%5%
288
April1st to 15thDay
38%10%24%15%8%2
269
16th to endDay
32%11%31%15%7%1
270
May1st to 15thDay
34%9%23%25%6%1
288
16th to endDay
33%7%20%21%12%3
330
June1st to 15thDay
30%7%24%23%11%2
376
16th to endDay
21%7%25%32%11%1
495
July1st to 15thDay
15%320%39%18%2
436
16th to endDay
16%222%37%17%4
327
August1st to 15thDay
13%217%37%22%7%
315
16th to endDay
14%416%38%20%6%
332
September1st to 15thDay
17%6%22%31%18%4
315
16th to endDay
27%6%18%26%19%2
315
October1st to 15thDay
30%7%21%23%15%1
315
16th to endDay
44%313%21%12%4
252
November1st to 15thDay
59%7%18%11%41
100
16th to endDay
54%6%10%8%11%8%
90
December1st to 15thDay
41%6%10%18%11%12%
90
16th to endDay
44%6%13%23%8%2
72
January1st to 15thNight
46%6%11%20%13%1
725
16th to endNight
41%5%11%25%14%1
768
February1st to 15thNight
38%5%16%27%9%1
704
16th to endNight
40%7%13%26%11%
632
March1st to 15thNight
44%7%14%21%10%1
720
16th to endNight
42%7%16%24%7%1
768
April1st to 15thNight
34%7%16%26%12%2
719
16th to endNight
31%6%16%29%14%1
558
May1st to 15thNight
25%7%10%31%23%2
360
16th to endNight
31%311%24%26%3
375
June1st to 15thNight
33%310%25%25%2
360
16th to endNight
24%312%29%26%3
360
July1st to 15thNight
11%37%31%39%6%
340
16th to endNight
11%36%26%42%7%
376
August1st to 15thNight
12%322%49%11%
431
16th to endNight
15%25%27%39%9%
654
September1st to 15thNight
13%27%29%37%9%
720
16th to endNight
26%28%28%29%3
716
October1st to 15thNight
28%312%29%22%2
720
16th to endNight
39%5%12%24%15%2
768
November1st to 15thNight
45%6%16%24%5%
760
16th to endNight
43%7%14%21%13%
780
December1st to 15thNight
39%5%13%28%10%2
780
16th to endNight
49%8%18%17%5%
792
Page generated at 2017-12-21 04:04:43. Version ac04

Copyright 2017 A. Danko


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