Delta Rocky Crest Resort
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Delta Rocky Crest Resort clear sky chart from 2005-11-05 to 2017-09-18.

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%
14937
12%
46688
8%
14902
35%
14902
16%
33953

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
12%
850
5%
2637
1%
847
15%
847
6%
2257
January16th to endNight
18%
768
11%
2499
6%
768
24%
768
9%
2022
February1st to 15thNight
17%
702
9%
2287
4%
701
23%
701
8%
1839
February16th to endNight
22%
631
10%
2030
5%
631
29%
631
11%
1554
March1st to 15thNight
21%
720
12%
1988
5%
720
27%
720
15%
1497
March16th to endNight
32%
768
19%
2112
11%
768
38%
768
23%
1428
April1st to 15thNight
24%
709
14%
1811
6%
709
29%
709
19%
1345
April16th to endNight
33%
540
18%
1620
10%
540
40%
540
21%
1117
May1st to 15thNight
37%
463
16%
1543
13%
463
43%
463
21%
1022
May16th to endNight
43%
374
13%
1497
12%
374
52%
374
22%
868
June1st to 15thNight
43%
360
11%
1346
11%
360
48%
360
20%
854
June16th to endNight
47%
360
12%
1260
12%
360
53%
360
23%
784
July1st to 15thNight
56%
340
16%
1190
20%
340
61%
340
33%
662
July16th to endNight
49%
450
14%
1484
14%
422
52%
422
26%
878
August1st to 15thNight
56%
539
16%
1609
13%
536
59%
536
30%
992
August16th to endNight
53%
603
18%
1749
10%
603
58%
603
32%
1075
September1st to 15thNight
47%
720
14%
1815
7%
720
50%
720
30%
1216
September16th to endNight
47%
669
20%
1865
13%
669
51%
669
29%
1227
October1st to 15thNight
30%
660
15%
1980
10%
660
37%
660
17%
1430
October16th to endNight
19%
704
10%
2117
5%
704
26%
704
10%
1679
November1st to 15thNight
27%
700
15%
2422
13%
700
34%
700
15%
1719
November16th to endNight
17%
720
9%
2520
6%
720
22%
720
9%
1987
December1st to 15thNight
11%
720
4%
2520
2%
720
14%
720
5%
2140
December16th to endNight
10%
867
7%
2787
2%
867
15%
867
6%
2361

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
18%10%46%5%24446%32%
48096
Night
18%11%47%5%24446%30%
46854
Cloud CoverDay
18%10%36%5%3445%6%32%
48106
Night
18%11%47%5%24446%30%
46859
TransparencyDay
52%5%11%19%9%
47781
Night
54%5%11%18%9%
46688
SeeingDay
22%11%29%21%10%3
5725
Night
24%11%27%25%10%1
14942

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 15thDay
19%19%6%10%5%3333418%
1297
16th to endDay
13%19%8%10%6%34345%19%
1722
February1st to 15thDay
13%17%7%12%8%34336%19%
1575
16th to endDay
15%17%7%10%6%3433323%
1441
March1st to 15thDay
15%12%5%7%6%35%346%30%
1960
16th to endDay
13%8%46%5%34446%38%
2112
April1st to 15thDay
22%10%35%5%24345%32%
2148
16th to endDay
21%8%25%423345%38%
2340
May1st to 15thDay
19%7%35%434446%34%
2406
16th to endDay
15%5%35%43446%7%40%
2618
June1st to 15thDay
18%6%35%6%35%45%8%33%
2610
16th to endDay
16%6%25%5%2446%9%34%
2700
July1st to 15thDay
13%4245%25%46%8%42%
2700
16th to endDay
13%425%5%35%5%6%8%39%
2578
August1st to 15thDay
12%6%25%6%35%45%7%40%
2340
16th to endDay
14%5%26%5%25%5%6%7%37%
2441
September1st to 15thDay
17%6%25%42445%6%39%
2142
16th to endDay
19%6%34434346%39%
1818
October1st to 15thDay
26%7%35%5%24336%31%
1650
16th to endDay
33%10%36%5%24445%20%
1752
November1st to 15thDay
23%11%36%5%245%5%7%24%
1435
16th to endDay
25%17%46%5%4443418%
1440
December1st to 15thDay
21%23%7%7%5%25%22416%
1440
16th to endDay
21%23%6%9%6%2333415%
1431
January1st to 15thNight
23%16%7%11%8%3333315%
2637
16th to endNight
15%16%9%11%7%3444420%
2499
February1st to 15thNight
13%17%7%11%6%45%445%19%
2285
16th to endNight
16%14%6%9%6%3444424%
2030
March1st to 15thNight
17%11%48%6%3444431%
1976
16th to endNight
14%8%37%5%14345%41%
2112
April1st to 15thNight
22%11%36%423336%32%
1811
16th to endNight
18%9%35%5%24347%35%
1620
May1st to 15thNight
17%8%25%5%2345%7%35%
1543
16th to endNight
13%5%145%345%6%9%41%
1495
June1st to 15thNight
14%7%25%33437%9%37%
1346
16th to endNight
14%6%2443345%9%39%
1260
July1st to 15thNight
10%42333445%7%50%
1260
16th to endNight
10%5%344236%5%8%43%
1585
August1st to 15thNight
10%5%24435%45%7%46%
1620
16th to endNight
12%5%24424448%45%
1749
September1st to 15thNight
13%42443445%8%43%
1815
16th to endNight
16%6%25%424346%43%
1865
October1st to 15thNight
23%7%26%42445%5%31%
1980
16th to endNight
29%9%46%5%23335%24%
2117
November1st to 15thNight
21%10%37%42445%7%28%
2422
16th to endNight
25%15%5%6%5%24345%20%
2520
December1st to 15thNight
21%23%7%8%5%2334413%
2520
16th to endNight
23%20%7%10%5%2332314%
2787

Percentage Cloud Cover SE (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
20%18%6%11%5%3424418%
1297
16th to endDay
13%19%8%10%7%3435%419%
1722
February1st to 15thDay
13%17%7%14%7%34345%18%
1575
16th to endDay
16%17%6%10%6%3433322%
1441
March1st to 15thDay
16%12%47%6%4435%6%29%
1971
16th to endDay
13%8%45%6%44446%37%
2111
April1st to 15thDay
22%10%45%5%2443432%
2148
16th to endDay
20%9%24423445%38%
2340
May1st to 15thDay
19%7%36%5%34446%34%
2406
16th to endDay
14%5%244345%5%7%40%
2618
June1st to 15thDay
18%6%345%35%45%8%33%
2610
16th to endDay
16%6%25%5%2446%9%34%
2700
July1st to 15thDay
13%4244245%6%8%42%
2700
16th to endDay
12%5%25%5%35%5%7%7%39%
2578
August1st to 15thDay
12%6%25%5%35%45%8%40%
2340
16th to endDay
14%5%25%5%35%5%5%8%37%
2441
September1st to 15thDay
17%6%25%43445%6%39%
2142
16th to endDay
19%6%24425%346%39%
1818
October1st to 15thDay
25%7%36%6%23346%30%
1650
16th to endDay
33%10%36%5%33445%20%
1752
November1st to 15thDay
22%11%36%5%3445%7%24%
1435
16th to endDay
25%16%46%5%3444418%
1440
December1st to 15thDay
21%23%7%10%42432316%
1440
16th to endDay
20%22%7%9%6%3333415%
1431
January1st to 15thNight
23%15%8%12%7%3333415%
2637
16th to endNight
14%16%8%12%7%2444419%
2499
February1st to 15thNight
12%17%7%11%7%36%445%18%
2278
16th to endNight
16%14%6%9%6%35%445%24%
2030
March1st to 15thNight
17%11%47%7%3443430%
1988
16th to endNight
14%7%37%5%13345%41%
2112
April1st to 15thNight
21%11%46%323345%32%
1811
16th to endNight
17%9%35%5%34437%35%
1620
May1st to 15thNight
17%8%25%42445%7%35%
1543
16th to endNight
13%5%144345%6%9%41%
1495
June1st to 15thNight
14%8%35%42446%8%37%
1346
16th to endNight
15%5%34435%35%9%39%
1260
July1st to 15thNight
10%424425%45%6%50%
1260
16th to endNight
9%5%3443446%8%44%
1585
August1st to 15thNight
10%5%245%25%45%8%45%
1620
16th to endNight
12%5%1442446%7%45%
1749
September1st to 15thNight
13%4245%35%45%8%41%
1815
16th to endNight
16%5%24424445%43%
1865
October1st to 15thNight
22%7%35%5%245%45%31%
1980
16th to endNight
29%10%47%5%2344424%
2117
November1st to 15thNight
21%10%37%43445%6%29%
2422
16th to endNight
25%15%47%5%24345%20%
2520
December1st to 15thNight
22%22%7%8%5%3334412%
2520
16th to endNight
22%21%7%10%6%2333414%
2787

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%410%10%4
1298
16th to endDay
68%47%10%7%1
1722
February1st to 15thDay
68%5%8%13%3
1577
16th to endDay
65%47%15%7%
1441
March1st to 15thDay
56%5%12%17%7%
1971
16th to endDay
47%49%19%15%3
2112
April1st to 15thDay
54%48%19%11%1
2148
16th to endDay
47%48%22%15%2
2340
May1st to 15thDay
49%5%9%20%13%1
2406
16th to endDay
41%6%13%23%12%1
2622
June1st to 15thDay
48%6%11%23%10%
2610
16th to endDay
45%6%15%20%11%
2700
July1st to 15thDay
36%7%13%27%13%1
2541
16th to endDay
41%6%12%26%12%
2417
August1st to 15thDay
42%8%14%22%11%
2327
16th to endDay
42%7%14%25%8%
2441
September1st to 15thDay
43%6%15%24%9%
2142
16th to endDay
46%5%12%27%7%
1818
October1st to 15thDay
55%411%18%10%
1650
16th to endDay
66%6%10%10%5%
1752
November1st to 15thDay
58%7%13%14%5%
1435
16th to endDay
69%410%12%31
1440
December1st to 15thDay
74%39%8%3
1440
16th to endDay
73%47%10%3
1431
January1st to 15thNight
73%48%8%4
2637
16th to endNight
67%5%6%12%7%
2499
February1st to 15thNight
67%5%9%13%4
2287
16th to endNight
61%410%15%7%
2030
March1st to 15thNight
56%412%17%7%
1988
16th to endNight
45%410%20%17%2
2112
April1st to 15thNight
54%37%19%13%1
1811
16th to endNight
48%48%18%17%2
1620
May1st to 15thNight
46%410%20%15%2
1543
16th to endNight
38%5%15%23%15%1
1497
June1st to 15thNight
43%6%12%23%13%
1346
16th to endNight
41%5%13%25%13%
1260
July1st to 15thNight
31%5%12%30%18%2
1190
16th to endNight
37%5%13%28%13%
1484
August1st to 15thNight
36%6%17%26%12%1
1609
16th to endNight
35%5%17%29%11%
1749
September1st to 15thNight
39%6%18%23%11%
1815
16th to endNight
41%412%32%8%
1865
October1st to 15thNight
52%6%11%19%10%
1980
16th to endNight
64%5%10%13%6%
2117
November1st to 15thNight
54%414%18%6%
2422
16th to endNight
65%412%13%2
2520
December1st to 15thNight
74%5%10%7%2
2520
16th to endNight
74%37%9%4
2787

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
21%28%36%10%3
60
16th to endDay
41%15%23%15%4
95
February1st to 15thDay
32%27%32%7%
90
16th to endDay
33%17%39%9%
81
March1st to 15thDay
23%18%31%20%6%
261
16th to endDay
19%13%35%18%9%2
288
April1st to 15thDay
28%11%30%19%8%2
270
16th to endDay
24%13%31%15%11%2
270
May1st to 15thDay
30%7%27%17%11%5%
288
16th to endDay
18%14%33%20%9%3
331
June1st to 15thDay
22%12%29%24%9%1
405
16th to endDay
18%10%35%26%6%2
495
July1st to 15thDay
14%8%32%25%15%3
475
16th to endDay
15%7%31%29%10%6%
326
August1st to 15thDay
17%224%30%15%9%
313
16th to endDay
21%5%19%23%18%11%
332
September1st to 15thDay
16%6%27%21%17%10%
315
16th to endDay
18%7%21%29%16%6%
262
October1st to 15thDay
28%10%30%19%9%2
255
16th to endDay
38%14%26%17%3
264
November1st to 15thDay
20%12%36%26%4
65
16th to endDay
30%25%28%16%
60
December1st to 15thDay
35%20%30%13%1
60
16th to endDay
39%35%20%13
64
January1st to 15thNight
30%16%30%17%31
852
16th to endNight
23%12%34%21%7%
768
February1st to 15thNight
22%15%34%22%5%
704
16th to endNight
24%15%31%22%7%
631
March1st to 15thNight
23%18%30%23%4
720
16th to endNight
18%11%29%27%11%1
768
April1st to 15thNight
28%13%28%23%6%
709
16th to endNight
22%10%29%26%10%
540
May1st to 15thNight
23%5%23%32%12%1
463
16th to endNight
14%5%32%32%15%
375
June1st to 15thNight
19%5%26%34%13%
360
16th to endNight
19%423%37%13%
360
July1st to 15thNight
10%321%42%20%1
340
16th to endNight
11%427%32%23%
450
August1st to 15thNight
14%417%36%24%2
539
16th to endNight
15%422%31%23%3
603
September1st to 15thNight
15%5%26%27%19%5%
720
16th to endNight
18%5%22%30%19%3
669
October1st to 15thNight
27%9%26%24%11%1
660
16th to endNight
34%14%25%19%5%
704
November1st to 15thNight
28%10%27%22%10%1
700
16th to endNight
36%12%26%19%5%
720
December1st to 15thNight
35%19%27%13%3
720
16th to endNight
32%16%29%17%3
867
Page generated at 2017-09-19 07:32:28. Version ac04

Copyright 2017 A. Danko


Delta Rocky Crest Resort Clear Sky Chart | Charts Home