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 2017-04-09.

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%
14093
9%
45218
8%
14065
40%
14065
13%
34652

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
32%
695
5%
1739
3%
695
32%
695
11%
1481
April16th to endNight
36%
511
7%
1501
6%
511
37%
511
12%
1203
May1st to 15thNight
48%
329
11%
1319
17%
329
48%
329
15%
896
May16th to endNight
40%
342
2%
1368
4%
342
40%
342
8%
1080
June1st to 15thNight
38%
330
3%
1261
4%
330
38%
330
10%
968
June16th to endNight
46%
330
5%
1155
5%
330
47%
330
14%
857
July1st to 15thNight
65%
310
11%
1118
15%
310
65%
310
27%
649
July16th to endNight
67%
348
15%
1304
25%
326
68%
326
29%
693
August1st to 15thNight
74%
395
20%
1377
25%
393
74%
393
33%
748
August16th to endNight
66%
599
18%
1649
15%
599
66%
599
36%
1004
September1st to 15thNight
69%
660
20%
1650
13%
660
70%
660
39%
1032
September16th to endNight
51%
656
17%
1801
15%
656
51%
656
23%
1288
October1st to 15thNight
48%
660
10%
1980
11%
660
49%
660
18%
1443
October16th to endNight
35%
704
7%
2189
7%
704
36%
704
12%
1741
November1st to 15thNight
24%
700
5%
2414
5%
700
26%
700
8%
2027
November16th to endNight
28%
720
6%
2520
5%
720
30%
720
9%
2051
December1st to 15thNight
31%
720
7%
2520
7%
720
32%
720
9%
2026
December16th to endNight
17%
773
5%
2717
4%
773
18%
773
6%
2362

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%
46071
Night
27%8%35%5%24345%28%
45379
Cloud CoverDay
31%9%35%423335%26%
46071
Night
32%8%25%423335%27%
45383
TransparencyDay
60%5%12%14%6%1
45735
Night
60%5%12%13%6%1
45219
SeeingDay
32%7%20%25%11%2
5205
Night
34%5%12%25%18%2
14101

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
28%13%38%6%35%445%15%
2072
16th to endDay
25%11%48%6%35%5%45%18%
2129
May1st to 15thDay
22%8%45%6%34446%30%
2301
16th to endDay
32%8%35%6%34445%19%
2391
June1st to 15thDay
28%9%36%5%25%445%23%
2366
16th to endDay
22%7%37%6%35%5%5%5%26%
2475
July1st to 15thDay
12%5%25%423435%49%
2437
16th to endDay
15%5%1431335%5%49%
2461
August1st to 15thDay
13%5%23323347%49%
2244
16th to endDay
14%5%25%434336%45%
2201
September1st to 15thDay
12%6%24322335%52%
1980
16th to endDay
22%8%24423346%36%
1828
October1st to 15thDay
23%8%36%43345%6%29%
1650
16th to endDay
36%7%26%5%2435%5%19%
1683
November1st to 15thDay
45%7%3433344315%
1444
16th to endDay
39%9%45%5%1433419%
1440
December1st to 15thDay
31%10%47%5%3434418%
1440
16th to endDay
37%12%45%6%2333316%
1495
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
24%10%47%7%35%5%5%5%18%
1739
16th to endNight
26%8%46%5%36%347%23%
1501
May1st to 15thNight
20%8%45%414446%35%
1319
16th to endNight
23%9%47%6%35%46%6%22%
1368
June1st to 15thNight
24%8%37%6%25%445%26%
1261
16th to endNight
18%8%48%6%25%44432%
1155
July1st to 15thNight
8%4245%24345%55%
1191
16th to endNight
10%5%24313236%55%
1400
August1st to 15thNight
8%314322448%56%
1385
16th to endNight
11%5%14322445%55%
1649
September1st to 15thNight
9%414313345%57%
1650
16th to endNight
20%7%25%414345%38%
1801
October1st to 15thNight
23%6%36%5%24445%33%
1980
16th to endNight
33%9%15%5%23345%22%
2189
November1st to 15thNight
38%8%35%6%34335%17%
2414
16th to endNight
35%10%35%5%2432421%
2520
December1st to 15thNight
32%9%46%5%23435%22%
2520
16th to endNight
38%13%37%5%2323314%
2717

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%34345%13%
2072
16th to endDay
31%12%37%6%3444317%
2129
May1st to 15thDay
28%8%345%34345%27%
2301
16th to endDay
36%9%37%5%24335%17%
2391
June1st to 15thDay
36%8%25%433335%20%
2366
16th to endDay
27%8%37%5%2445%5%25%
2475
July1st to 15thDay
16%5%245%13335%48%
2437
16th to endDay
18%5%1332435%5%46%
2461
August1st to 15thDay
17%5%13323447%47%
2244
16th to endDay
18%5%24424346%43%
2201
September1st to 15thDay
15%6%24322325%51%
1980
16th to endDay
29%5%245%23336%35%
1828
October1st to 15thDay
27%7%35%42345%6%29%
1650
16th to endDay
41%6%34423335%20%
1683
November1st to 15thDay
50%8%2343342214%
1444
16th to endDay
44%10%25%42222318%
1440
December1st to 15thDay
35%11%26%5%2334419%
1440
16th to endDay
40%15%45%5%2222216%
1495
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%10%37%6%3445%6%17%
1739
16th to endNight
31%9%37%424445%21%
1501
May1st to 15thNight
25%6%35%423445%34%
1319
16th to endNight
30%8%36%5%345%45%21%
1368
June1st to 15thNight
32%6%36%5%34335%24%
1261
16th to endNight
23%7%37%6%34335%31%
1155
July1st to 15thNight
12%42442333453%
1191
16th to endNight
13%5%24323336%52%
1400
August1st to 15thNight
10%5%12412346%57%
1385
16th to endNight
14%414422245%54%
1649
September1st to 15thNight
13%32342224456%
1650
16th to endNight
24%5%25%423335%38%
1801
October1st to 15thNight
27%5%25%433445%33%
1980
16th to endNight
38%7%24433345%21%
2189
November1st to 15thNight
45%7%2442334415%
2414
16th to endNight
41%8%35%42332420%
2520
December1st to 15thNight
36%10%35%323335%21%
2520
16th to endNight
43%14%25%5%2222314%
2717

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%
2072
16th to endDay
70%5%12%8%2
2129
May1st to 15thDay
57%5%15%16%5%
2301
16th to endDay
69%7%14%8%1
2395
June1st to 15thDay
66%5%14%8%4
2366
16th to endDay
59%7%15%13%3
2475
July1st to 15thDay
40%6%13%24%14%1
2281
16th to endDay
36%6%13%25%15%2
2294
August1st to 15thDay
38%5%17%27%10%1
2227
16th to endDay
42%415%27%7%2
2201
September1st to 15thDay
36%414%24%17%3
1980
16th to endDay
51%5%14%16%8%3
1828
October1st to 15thDay
55%6%12%17%6%
1650
16th to endDay
67%49%12%5%
1683
November1st to 15thDay
73%5%9%6%21
1444
16th to endDay
72%46%8%5%1
1440
December1st to 15thDay
69%6%7%11%5%
1440
16th to endDay
76%37%7%4
1495
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
1739
16th to endNight
63%6%14%11%3
1501
May1st to 15thNight
52%417%17%7%
1320
16th to endNight
63%8%17%7%2
1368
June1st to 15thNight
63%5%14%11%5%
1261
16th to endNight
56%6%15%16%31
1155
July1st to 15thNight
36%5%13%27%13%3
1118
16th to endNight
32%414%27%17%3
1304
August1st to 15thNight
29%6%15%33%11%2
1377
16th to endNight
33%5%19%29%10%1
1649
September1st to 15thNight
31%6%14%24%18%4
1650
16th to endNight
48%5%12%17%11%2
1801
October1st to 15thNight
53%6%12%18%7%1
1980
16th to endNight
64%411%12%5%
2189
November1st to 15thNight
71%5%11%7%12
2414
16th to endNight
69%48%9%8%
2520
December1st to 15thNight
67%5%10%10%5%
2520
16th to endNight
76%47%7%3
2717

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
40%10%22%15%9%2
244
16th to endDay
30%12%28%16%8%2
210
May1st to 15thDay
32%9%24%25%6%1
228
16th to endDay
37%6%21%21%11%1
266
June1st to 15thDay
28%8%25%24%11%1
311
16th to endDay
22%6%25%32%10%1
420
July1st to 15thDay
17%420%38%16%2
365
16th to endDay
17%222%35%17%4
271
August1st to 15thDay
14%220%41%16%4
255
16th to endDay
15%419%38%16%5%
268
September1st to 15thDay
19%7%23%29%17%2
255
16th to endDay
26%7%18%27%18%2
255
October1st to 15thDay
31%8%20%24%13%
255
16th to endDay
45%414%24%9%3
195
November1st to 15thDay
59%7%17%11%2
67
16th to endDay
48%5%8%11%13%13%
60
December1st to 15thDay
50%10%15%21%11
60
16th to endDay
40%7%15%23%9%3
64
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
33%7%15%26%13%2
695
16th to endNight
30%6%15%29%16%1
511
May1st to 15thNight
25%7%9%30%24%2
330
16th to endNight
32%311%25%24%3
343
June1st to 15thNight
33%311%24%24%2
330
16th to endNight
25%312%29%26%2
330
July1st to 15thNight
12%37%32%37%7%
310
16th to endNight
12%47%27%41%7%
348
August1st to 15thNight
13%1322%49%9%
395
16th to endNight
16%26%28%37%9%
599
September1st to 15thNight
13%27%30%36%9%
660
16th to endNight
27%38%28%28%3
656
October1st to 15thNight
28%313%29%21%3
660
16th to endNight
40%5%12%24%13%2
704
November1st to 15thNight
44%6%17%25%5%
700
16th to endNight
41%7%14%20%14%
720
December1st to 15thNight
41%5%14%29%8%
720
16th to endNight
48%8%18%17%6%
773
Page generated at 2017-04-10 06:00:39. Version ac04

Copyright 2017 A. Danko


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