Pinetop Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Pinetop Observatory clear sky chart from 2005-11-05 to 2017-10-31.

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
44%
15598
20%
47476
13%
15562
53%
15562
25%
30177

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
26%
716
22%
2327
9%
716
41%
716
18%
1458
January16th to endNight
22%
768
22%
2496
9%
768
39%
768
20%
1569
February1st to 15thNight
25%
701
20%
2287
7%
701
42%
701
21%
1384
February16th to endNight
23%
631
24%
1908
10%
631
39%
631
21%
1212
March1st to 15thNight
30%
720
21%
1980
10%
720
41%
720
23%
1286
March16th to endNight
31%
768
18%
2112
10%
768
38%
768
22%
1428
April1st to 15thNight
32%
718
18%
1832
6%
718
40%
718
26%
1213
April16th to endNight
43%
684
20%
1764
9%
684
49%
684
29%
1168
May1st to 15thNight
45%
540
15%
1620
8%
540
50%
540
22%
1112
May16th to endNight
58%
501
16%
1624
13%
501
61%
501
25%
1047
June1st to 15thNight
66%
360
17%
1440
20%
360
71%
360
25%
843
June16th to endNight
67%
360
17%
1440
18%
360
73%
360
26%
819
July1st to 15thNight
65%
493
12%
1513
11%
493
66%
493
25%
995
July16th to endNight
77%
564
16%
1595
14%
531
79%
531
34%
968
August1st to 15thNight
69%
539
18%
1609
15%
536
69%
536
27%
1067
August16th to endNight
67%
702
17%
1848
13%
702
68%
702
29%
1271
September1st to 15thNight
63%
720
25%
1812
17%
720
65%
720
34%
1172
September16th to endNight
54%
717
21%
2007
18%
717
57%
717
27%
1336
October1st to 15thNight
52%
720
22%
2160
21%
720
57%
720
27%
1368
October16th to endNight
42%
768
29%
2303
20%
768
56%
768
31%
1350
November1st to 15thNight
46%
700
27%
2113
20%
700
57%
700
29%
1270
November16th to endNight
38%
720
20%
2520
15%
720
49%
720
22%
1519
December1st to 15thNight
33%
720
19%
2520
11%
720
44%
720
17%
1629
December16th to endNight
32%
768
22%
2646
11%
768
47%
768
19%
1693

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
12%5%245%35%5%5%7%41%
48246
Night
12%5%2442445%7%45%
47669
Cloud CoverDay
12%5%25%5%35%5%6%7%41%
48256
Night
11%5%2443445%7%44%
47673
TransparencyDay
40%8%12%20%14%2
47957
Night
37%7%12%22%16%3
47476
SeeingDay
15%9%21%24%18%9%
5778
Night
16%9%23%31%16%1
15607

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
14%4346%3446%6%39%
1611
16th to endDay
13%7%35%434345%44%
1728
February1st to 15thDay
11%7%36%5%25%446%41%
1575
16th to endDay
11%5%46%5%2445%6%42%
1560
March1st to 15thDay
13%6%245%235%4445%
1969
16th to endDay
14%7%345%3445%6%39%
2112
April1st to 15thDay
10%6%2442445%6%48%
2116
16th to endDay
15%5%25%42435%6%44%
2205
May1st to 15thDay
17%5%246%35%5%5%7%35%
2331
16th to endDay
13%5%26%5%36%5%5%8%37%
2488
June1st to 15thDay
10%415%5%35%5%6%9%41%
2520
16th to endDay
8%3246%35%6%8%10%40%
2520
July1st to 15thDay
11%4247%37%6%7%9%35%
2352
16th to endDay
7%425%5%46%6%9%11%35%
2465
August1st to 15thDay
10%425%6%47%6%7%9%35%
2340
16th to endDay
10%425%6%36%7%6%9%36%
2341
September1st to 15thDay
12%424435%5%46%46%
2145
16th to endDay
16%6%25%5%245%5%6%38%
1952
October1st to 15thDay
18%5%14214345%47%
1800
16th to endDay
13%414324346%51%
1920
November1st to 15thDay
12%5%23223445%52%
1741
16th to endDay
15%434324446%47%
1440
December1st to 15thDay
14%5%2342345%7%45%
1440
16th to endDay
17%7%33424446%41%
1575
January1st to 15thNight
13%5%25%425%45%6%44%
2327
16th to endNight
13%7%2442435%5%43%
2496
February1st to 15thNight
13%6%24324446%46%
2285
16th to endNight
10%5%25%5%25%5%5%7%42%
1908
March1st to 15thNight
14%424433447%46%
1968
16th to endNight
15%6%245%24446%43%
2112
April1st to 15thNight
12%4344345%5%6%45%
1832
16th to endNight
14%325%3245%47%46%
1764
May1st to 15thNight
15%5%25%5%3445%8%40%
1620
16th to endNight
12%4144245%6%8%43%
1622
June1st to 15thNight
8%324435%5%7%10%45%
1440
16th to endNight
6%424335%5%6%9%47%
1440
July1st to 15thNight
9%425%5%35%5%6%9%42%
1603
16th to endNight
4213436%6%9%12%45%
1703
August1st to 15thNight
9%425%5%445%6%8%43%
1620
16th to endNight
8%425%6%46%6%6%9%39%
1848
September1st to 15thNight
10%41441445%7%48%
1812
16th to endNight
15%5%25%424446%43%
2007
October1st to 15thNight
15%5%14424446%46%
2160
16th to endNight
12%31442345%5%52%
2303
November1st to 15thNight
12%5%24323335%53%
2113
16th to endNight
15%5%24424446%47%
2520
December1st to 15thNight
14%6%25%5%245%4442%
2520
16th to endNight
15%6%24434446%41%
2646

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
13%5%25%5%445%5%6%40%
1611
16th to endDay
13%6%35%434346%43%
1728
February1st to 15thDay
11%7%35%5%35%45%6%41%
1575
16th to endDay
11%5%36%5%345%6%6%42%
1560
March1st to 15thDay
13%6%25%42445%5%45%
1980
16th to endDay
14%8%345%3445%7%38%
2111
April1st to 15thDay
9%6%2442445%7%47%
2116
16th to endDay
14%6%2442445%7%43%
2205
May1st to 15thDay
16%5%35%5%35%5%6%6%35%
2331
16th to endDay
12%5%25%5%46%5%5%8%37%
2488
June1st to 15thDay
10%3245%46%5%7%8%41%
2520
16th to endDay
6%4246%45%6%8%10%40%
2520
July1st to 15thDay
10%426%6%37%6%6%9%34%
2352
16th to endDay
7%425%6%47%6%9%11%34%
2465
August1st to 15thDay
9%5%25%6%45%7%8%10%33%
2340
16th to endDay
10%5%25%5%36%7%8%8%35%
2341
September1st to 15thDay
11%4245%35%446%46%
2145
16th to endDay
16%6%245%25%5%6%6%37%
1952
October1st to 15thDay
17%5%24323346%46%
1800
16th to endDay
12%424323436%51%
1920
November1st to 15thDay
11%5%23323445%52%
1741
16th to endDay
14%5%24423446%46%
1440
December1st to 15thDay
13%6%2442435%7%45%
1440
16th to endDay
16%8%24424447%40%
1575
January1st to 15thNight
13%5%25%425%46%7%43%
2327
16th to endNight
12%7%35%424446%43%
2496
February1st to 15thNight
12%6%24325%447%46%
2278
16th to endNight
9%6%345%35%5%47%43%
1908
March1st to 15thNight
14%5%2343345%7%45%
1980
16th to endNight
14%6%25%434446%42%
2112
April1st to 15thNight
11%4344345%6%6%44%
1832
16th to endNight
13%42442445%7%45%
1764
May1st to 15thNight
14%5%345%34447%41%
1619
16th to endNight
11%425%425%5%6%9%42%
1622
June1st to 15thNight
7%4234346%6%10%44%
1440
16th to endNight
6%3344345%6%9%47%
1440
July1st to 15thNight
9%4245%346%6%9%43%
1603
16th to endNight
3213436%7%7%13%44%
1703
August1st to 15thNight
8%425%6%35%5%5%9%42%
1620
16th to endNight
8%425%6%36%5%7%8%39%
1848
September1st to 15thNight
10%4245%2445%8%48%
1812
16th to endNight
15%5%25%4245%45%43%
2007
October1st to 15thNight
15%425%433346%46%
2160
16th to endNight
12%31442345%5%51%
2303
November1st to 15thNight
12%6%24323245%52%
2113
16th to endNight
13%5%25%424445%47%
2520
December1st to 15thNight
13%6%35%6%345%4442%
2520
16th to endNight
14%6%25%43445%7%41%
2646

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
42%7%12%18%15%3
1612
16th to endDay
42%49%22%16%3
1728
February1st to 15thDay
42%6%10%20%16%3
1577
16th to endDay
40%6%13%21%14%3
1560
March1st to 15thDay
40%6%10%21%16%3
1980
16th to endDay
44%8%10%19%12%3
2112
April1st to 15thDay
35%6%12%22%17%5%
2116
16th to endDay
40%7%11%19%15%5%
2205
May1st to 15thDay
46%11%12%16%11%1
2331
16th to endDay
43%10%15%20%9%1
2492
June1st to 15thDay
38%10%15%22%11%
2520
16th to endDay
35%12%17%19%12%1
2520
July1st to 15thDay
43%11%13%16%12%2
2213
16th to endDay
38%14%15%19%10%1
2310
August1st to 15thDay
42%12%14%19%11%
2327
16th to endDay
41%13%15%19%8%1
2341
September1st to 15thDay
39%7%12%19%17%3
2145
16th to endDay
44%8%10%19%15%1
1952
October1st to 15thDay
38%6%10%26%13%4
1800
16th to endDay
33%5%9%27%19%4
1920
November1st to 15thDay
34%49%20%23%6%
1741
16th to endDay
38%6%9%23%19%3
1440
December1st to 15thDay
38%6%12%21%15%4
1440
16th to endDay
43%6%10%23%13%2
1575
January1st to 15thNight
39%6%12%17%18%5%
2327
16th to endNight
41%411%23%16%2
2496
February1st to 15thNight
37%5%11%23%17%3
2287
16th to endNight
37%6%12%23%16%2
1908
March1st to 15thNight
38%6%12%25%13%3
1980
16th to endNight
42%7%12%20%15%1
2112
April1st to 15thNight
36%8%13%21%15%4
1832
16th to endNight
36%8%13%19%17%4
1764
May1st to 15thNight
43%8%14%20%11%1
1620
16th to endNight
36%10%15%25%9%1
1624
June1st to 15thNight
32%11%17%24%13%1
1440
16th to endNight
31%9%17%20%17%2
1440
July1st to 15thNight
37%11%16%19%11%3
1513
16th to endNight
26%12%20%27%12%
1595
August1st to 15thNight
37%11%13%22%14%1
1609
16th to endNight
37%10%15%24%9%2
1848
September1st to 15thNight
33%8%14%20%19%3
1812
16th to endNight
40%7%11%21%17%1
2007
October1st to 15thNight
39%5%10%24%16%2
2160
16th to endNight
32%5%9%25%23%3
2303
November1st to 15thNight
35%47%20%24%8%
2113
16th to endNight
38%5%10%22%19%4
2520
December1st to 15thNight
43%6%9%20%16%3
2520
16th to endNight
42%6%12%21%14%2
2646

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%33%27%13%41
90
16th to endDay
27%26%33%12%1
96
February1st to 15thDay
18%37%37%41
90
16th to endDay
20%20%31%23%4
156
March1st to 15thDay
17%20%30%22%7%1
270
16th to endDay
17%17%29%25%6%3
288
April1st to 15thDay
13%18%24%26%14%2
270
16th to endDay
22%7%22%23%17%7%
270
May1st to 15thDay
22%17%24%16%12%7%
288
16th to endDay
18%323%22%20%12%
331
June1st to 15thDay
12%423%25%24%11%
315
16th to endDay
10%5%24%29%20%9%
315
July1st to 15thDay
14%121%30%23%6%
305
16th to endDay
6%19%34%28%19%
326
August1st to 15thDay
12%117%22%29%15%
313
16th to endDay
9%8%32%25%22%
332
September1st to 15thDay
13%5%15%20%24%21%
315
16th to endDay
21%415%21%23%12%
314
October1st to 15thDay
19%5%16%28%23%7%
315
16th to endDay
12%13%25%25%18%5%
336
November1st to 15thDay
19%8%20%28%19%4
252
16th to endDay
20%10%36%21%8%3
60
December1st to 15thDay
18%21%31%16%8%3
60
16th to endDay
22%29%28%16%2
71
January1st to 15thNight
18%20%30%24%5%
720
16th to endNight
20%15%36%26%1
768
February1st to 15thNight
18%16%34%28%1
704
16th to endNight
16%19%35%25%2
631
March1st to 15thNight
20%16%30%27%5%
720
16th to endNight
20%12%31%26%7%1
768
April1st to 15thNight
13%18%33%26%7%
718
16th to endNight
16%8%27%32%14%
684
May1st to 15thNight
18%5%24%33%16%1
540
16th to endNight
14%117%35%27%2
503
June1st to 15thNight
9%116%43%28%1
360
16th to endNight
6%216%47%25%1
360
July1st to 15thNight
11%211%34%37%2
493
16th to endNight
410%33%41%9%
564
August1st to 15thNight
12%8%37%35%4
539
16th to endNight
10%9%34%38%4
702
September1st to 15thNight
12%214%32%33%5%
720
16th to endNight
18%215%31%27%4
717
October1st to 15thNight
19%6%16%32%21%3
720
16th to endNight
15%10%27%28%16%1
768
November1st to 15thNight
16%11%20%34%14%2
700
16th to endNight
17%14%25%29%11%1
720
December1st to 15thNight
19%11%29%30%8%
720
16th to endNight
19%14%28%34%3
768
Page generated at 2017-11-01 17:23:30. Version ac04

Copyright 2017 A. Danko


Pinetop Observatory Clear Sky Chart |Charts Home