Sunrise Point
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Sunrise Point clear sky chart from 2005-11-05 to 2018-02-14.

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
36%
15138
10%
48686
10%
15110
38%
15110
14%
36557

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
28%
780
9%
2716
7%
776
31%
776
9%
2200
January16th to endNight
31%
832
9%
2883
9%
832
33%
832
10%
2290
February1st to 15thNight
26%
753
7%
2470
5%
753
30%
753
8%
2050
February16th to endNight
25%
632
9%
1987
6%
632
28%
632
9%
1633
March1st to 15thNight
22%
720
5%
2091
4%
720
24%
720
8%
1803
March16th to endNight
21%
768
4%
2049
3%
768
22%
768
7%
1808
April1st to 15thNight
24%
719
4%
1799
2%
719
25%
719
9%
1559
April16th to endNight
30%
583
8%
1663
6%
583
32%
583
12%
1354
May1st to 15thNight
41%
359
12%
1439
15%
359
43%
359
13%
1010
May16th to endNight
41%
374
6%
1496
9%
374
43%
374
10%
1146
June1st to 15thNight
37%
360
5%
1440
5%
360
39%
360
12%
1055
June16th to endNight
44%
360
9%
1309
11%
360
45%
360
19%
856
July1st to 15thNight
68%
340
14%
1327
19%
340
71%
340
34%
661
July16th to endNight
71%
376
23%
1416
35%
354
76%
354
44%
604
August1st to 15thNight
75%
436
24%
1509
27%
434
77%
434
45%
701
August16th to endNight
64%
670
27%
1816
18%
670
67%
670
44%
1008
September1st to 15thNight
65%
720
24%
1800
14%
720
66%
720
46%
1051
September16th to endNight
50%
716
20%
1962
16%
716
52%
716
26%
1317
October1st to 15thNight
39%
720
13%
2160
12%
720
42%
720
19%
1543
October16th to endNight
36%
768
12%
2388
11%
768
39%
768
14%
1808
November1st to 15thNight
20%
760
6%
2594
4%
760
24%
760
7%
2186
November16th to endNight
27%
780
6%
2730
5%
780
28%
780
8%
2243
December1st to 15thNight
31%
780
7%
2730
8%
780
31%
780
10%
2165
December16th to endNight
16%
832
6%
2912
4%
832
18%
832
5%
2506

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
10%17%6%8%6%34445%29%
49399
Night
8%15%6%9%7%35%445%28%
48854
Cloud CoverDay
7%12%5%8%7%35%5%5%7%31%
49399
Night
410%5%9%8%46%6%6%7%30%
48858
TransparencyDay
53%8%10%15%9%2
49070
Night
54%9%10%13%9%2
48687
SeeingDay
20%23%27%19%7%2
6065
Night
14%18%25%24%14%2
15147

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
9%20%9%10%7%34435%19%
1552
16th to endDay
8%21%9%11%5%3445%421%
1690
February1st to 15thDay
8%17%9%12%8%37%6%5%6%14%
1694
16th to endDay
8%22%10%15%8%4433315%
1487
March1st to 15thDay
7%28%11%13%6%36%5%3310%
1868
16th to endDay
9%32%12%11%8%343237%
2175
April1st to 15thDay
11%27%9%10%6%3433414%
2149
16th to endDay
8%25%8%10%7%33445%17%
2295
May1st to 15thDay
11%21%47%5%36%445%25%
2511
16th to endDay
18%19%48%6%35%45%5%17%
2615
June1st to 15thDay
18%13%47%5%35%5%5%5%23%
2520
16th to endDay
13%12%46%6%3445%6%31%
2644
July1st to 15thDay
6%5%24324335%57%
2547
16th to endDay
6%313323345%63%
2657
August1st to 15thDay
6%41332335%8%58%
2442
16th to endDay
6%5%14424448%50%
2384
September1st to 15thDay
8%5%2442335%5%55%
2160
16th to endDay
15%12%36%5%2335%437%
1997
October1st to 15thDay
16%16%36%4345%45%30%
1800
16th to endDay
15%18%49%5%3333327%
1836
November1st to 15thDay
12%27%6%10%6%45%45%411%
1592
16th to endDay
10%24%8%10%7%35%33317%
1560
December1st to 15thDay
8%16%8%13%8%35%345%21%
1560
16th to endDay
6%24%10%11%7%3443317%
1664
January1st to 15thNight
9%17%8%11%8%45%5%4420%
2716
16th to endNight
7%19%9%10%8%36%445%20%
2883
February1st to 15thNight
8%16%7%10%9%46%7%5%6%17%
2458
16th to endNight
6%16%9%13%8%46%5%35%20%
1987
March1st to 15thNight
6%19%11%13%9%46%5%5%414%
2091
16th to endNight
7%22%11%13%8%46%6%4411%
2045
April1st to 15thNight
7%21%10%12%8%46%435%16%
1799
16th to endNight
8%19%6%10%7%5%5%5%5%6%19%
1663
May1st to 15thNight
8%16%5%8%6%35%5%5%5%29%
1439
16th to endNight
12%14%6%10%7%45%45%6%21%
1496
June1st to 15thNight
13%14%49%6%45%45%5%25%
1440
16th to endNight
9%11%47%7%35%45%7%33%
1309
July1st to 15thNight
4324424435%61%
1407
16th to endNight
3312312335%67%
1512
August1st to 15thNight
3312312347%66%
1517
16th to endNight
4424323345%59%
1816
September1st to 15thNight
4414323346%59%
1800
16th to endNight
9%9%37%5%3445%5%40%
1962
October1st to 15thNight
12%15%47%6%2344434%
2160
16th to endNight
11%16%5%9%7%34445%26%
2388
November1st to 15thNight
12%21%6%11%8%46%43415%
2594
16th to endNight
6%20%8%14%8%45%43418%
2730
December1st to 15thNight
6%17%7%12%8%45%5%4422%
2730
16th to endNight
9%21%10%13%7%35%44315%
2912

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
311%7%13%11%5%6%6%5%6%22%
1552
16th to endDay
414%8%9%7%37%7%6%6%23%
1690
February1st to 15thDay
413%6%10%9%46%7%7%8%21%
1694
16th to endDay
416%8%13%9%5%7%446%18%
1487
March1st to 15thDay
216%9%14%9%46%7%6%7%14%
1868
16th to endDay
424%9%13%10%5%6%5%45%10%
2175
April1st to 15thDay
8%22%7%11%7%36%437%16%
2149
16th to endDay
7%20%6%9%7%45%447%22%
2295
May1st to 15thDay
8%18%47%7%45%5%5%8%26%
2511
16th to endDay
18%16%47%6%35%46%7%19%
2615
June1st to 15thDay
14%12%5%7%6%35%5%6%8%24%
2520
16th to endDay
11%9%46%6%46%5%5%7%32%
2644
July1st to 15thDay
4414324347%58%
2547
16th to endDay
4322323446%63%
2657
August1st to 15thDay
431332345%8%59%
2442
16th to endDay
3415%5%3445%7%52%
2384
September1st to 15thDay
5%5%14323347%57%
2160
16th to endDay
10%8%46%6%3435%6%39%
1997
October1st to 15thDay
10%14%37%5%35%45%6%32%
1800
16th to endDay
8%13%49%7%47%5%5%5%28%
1836
November1st to 15thDay
5%14%7%12%9%47%6%7%8%15%
1592
16th to endDay
5%15%8%11%9%5%7%5%45%21%
1560
December1st to 15thDay
310%6%12%9%5%5%5%6%8%24%
1560
16th to endDay
312%7%14%10%5%8%7%5%6%20%
1664
January1st to 15thNight
49%6%12%9%47%6%8%9%21%
2716
16th to endNight
312%6%10%9%47%6%5%8%24%
2883
February1st to 15thNight
410%6%11%7%47%7%7%9%22%
2458
16th to endNight
39%7%12%9%5%7%7%6%6%23%
1987
March1st to 15thNight
210%7%11%11%5%9%7%6%8%18%
2091
16th to endNight
313%8%12%9%6%8%7%6%6%15%
2049
April1st to 15thNight
5%15%6%10%12%5%6%5%5%8%18%
1799
16th to endNight
5%14%6%9%8%47%6%5%8%22%
1663
May1st to 15thNight
7%12%47%7%36%5%5%8%30%
1439
16th to endNight
9%11%48%9%46%5%7%8%24%
1496
June1st to 15thNight
10%11%47%7%46%7%6%7%26%
1440
16th to endNight
6%7%36%6%48%6%6%7%35%
1309
July1st to 15thNight
3213425%446%61%
1407
16th to endNight
2213314346%66%
1512
August1st to 15thNight
2213213448%64%
1517
16th to endNight
2315%33445%7%59%
1816
September1st to 15thNight
43134135%5%7%59%
1800
16th to endNight
7%6%27%6%446%6%6%42%
1962
October1st to 15thNight
7%10%38%6%35%5%5%5%37%
2160
16th to endNight
6%10%49%8%46%6%7%7%29%
2388
November1st to 15thNight
413%6%10%10%6%8%7%6%7%18%
2594
16th to endNight
211%412%11%6%7%6%6%7%22%
2730
December1st to 15thNight
311%6%10%9%5%8%6%6%7%24%
2730
16th to endNight
414%7%12%10%5%6%6%6%8%16%
2912

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
65%9%7%9%7%1
1552
16th to endDay
63%8%7%9%7%3
1690
February1st to 15thDay
64%11%7%10%31
1694
16th to endDay
71%7%6%9%4
1487
March1st to 15thDay
73%10%6%6%2
1868
16th to endDay
79%7%6%5%
2175
April1st to 15thDay
70%9%10%8%1
2149
16th to endDay
65%10%11%8%3
2295
May1st to 15thDay
55%8%12%16%6%
2511
16th to endDay
63%11%11%11%2
2619
June1st to 15thDay
55%11%16%10%5%1
2520
16th to endDay
47%10%15%16%8%1
2644
July1st to 15thDay
27%7%11%25%21%5%
2398
16th to endDay
20%6%11%26%25%8%
2490
August1st to 15thDay
21%7%15%31%18%5%
2425
16th to endDay
28%8%13%28%17%3
2384
September1st to 15thDay
27%5%12%23%25%4
2160
16th to endDay
46%7%13%17%11%4
1997
October1st to 15thDay
51%6%10%19%10%1
1800
16th to endDay
60%5%7%15%10%1
1836
November1st to 15thDay
71%9%7%7%21
1592
16th to endDay
69%6%5%8%7%1
1560
December1st to 15thDay
63%9%7%10%7%1
1560
16th to endDay
68%8%8%8%5%
1664
January1st to 15thNight
63%9%7%8%7%2
2716
16th to endNight
62%8%7%8%6%5%
2883
February1st to 15thNight
63%12%8%9%5%1
2470
16th to endNight
64%8%8%11%5%
1987
March1st to 15thNight
66%12%8%9%3
2091
16th to endNight
68%12%8%7%1
2049
April1st to 15thNight
67%10%10%8%2
1799
16th to endNight
59%11%10%12%3
1663
May1st to 15thNight
50%9%12%17%7%1
1440
16th to endNight
56%12%15%12%3
1496
June1st to 15thNight
53%10%14%14%6%
1440
16th to endNight
41%11%18%19%8%1
1309
July1st to 15thNight
23%9%12%26%21%7%
1327
16th to endNight
17%6%12%24%28%10%
1416
August1st to 15thNight
16%8%13%29%24%7%
1509
16th to endNight
23%6%14%30%20%3
1816
September1st to 15thNight
22%8%12%23%26%6%
1800
16th to endNight
39%9%13%17%13%6%
1962
October1st to 15thNight
48%8%9%19%11%1
2160
16th to endNight
56%7%8%13%11%1
2388
November1st to 15thNight
68%8%9%9%21
2594
16th to endNight
65%9%5%7%8%2
2730
December1st to 15thNight
61%9%9%10%7%1
2730
16th to endNight
69%10%7%6%4
2912

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
12%22%24%20%17%3
90
16th to endDay
22%40%20%8%8%
122
February1st to 15thDay
25%29%27%12%4
276
16th to endDay
24%33%21%15%4
223
March1st to 15thDay
27%43%20%7%
270
16th to endDay
33%35%20%9%1
288
April1st to 15thDay
26%31%23%11%42
269
16th to endDay
28%34%19%11%32
270
May1st to 15thDay
26%22%29%17%21
288
16th to endDay
26%17%24%22%7%2
330
June1st to 15thDay
21%24%26%18%7%1
315
16th to endDay
19%21%31%17%8%1
439
July1st to 15thDay
8%13%36%32%7%
332
16th to endDay
415%37%29%10%3
327
August1st to 15thDay
7%9%33%28%12%7%
315
16th to endDay
6%12%32%30%11%6%
332
September1st to 15thDay
13%15%30%26%10%3
315
16th to endDay
19%19%28%24%8%
315
October1st to 15thDay
24%25%24%18%6%
315
16th to endDay
28%19%26%16%8%1
252
November1st to 15thDay
21%39%29%9%
106
16th to endDay
27%26%26%8%8%1
90
December1st to 15thDay
18%31%22%12%11%4
90
16th to endDay
17%25%36%12%7%1
96
January1st to 15thNight
19%26%22%20%10%1
780
16th to endNight
15%23%25%22%9%2
832
February1st to 15thNight
16%20%29%22%9%
760
16th to endNight
17%21%28%23%7%
632
March1st to 15thNight
15%27%28%19%7%
720
16th to endNight
16%27%30%17%6%1
768
April1st to 15thNight
16%21%30%21%8%2
719
16th to endNight
13%20%28%22%11%2
583
May1st to 15thNight
13%16%22%28%16%3
360
16th to endNight
13%13%23%28%20%1
375
June1st to 15thNight
15%12%29%27%15%
360
16th to endNight
11%11%27%29%19%
360
July1st to 15thNight
4320%40%30%1
340
16th to endNight
25%17%39%31%3
376
August1st to 15thNight
4313%34%36%7%
436
16th to endNight
5%5%20%30%30%6%
670
September1st to 15thNight
7%5%18%29%31%7%
720
16th to endNight
12%11%21%29%21%3
716
October1st to 15thNight
17%13%25%24%16%3
720
16th to endNight
19%18%21%24%12%3
768
November1st to 15thNight
21%23%30%19%4
760
16th to endNight
18%27%22%19%11%1
780
December1st to 15thNight
15%21%28%22%10%1
780
16th to endNight
17%28%34%13%5%
832
Page generated at 2018-02-15 07:58:51. Version ac04

Copyright 2018 A. Danko


Sunrise Point Clear Sky Chart |Charts Home