Greene
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Greene clear sky chart from 2005-11-05 to 2017-03-22.

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
28%
14295
16%
45466
7%
14263
38%
14263
19%
30382

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
21%
720
18%
2506
7%
716
36%
716
17%
1602
January16th to endNight
16%
768
17%
2688
4%
768
32%
768
14%
1778
February1st to 15thNight
17%
704
14%
2258
4%
701
29%
701
13%
1594
February16th to endNight
20%
631
19%
1893
6%
631
35%
631
17%
1303
March1st to 15thNight
18%
720
15%
2127
5%
720
29%
720
16%
1513
March16th to endNight
25%
732
20%
1976
7%
732
36%
732
22%
1308
April1st to 15thNight
20%
655
18%
1643
3%
655
29%
655
20%
1185
April16th to endNight
25%
495
16%
1485
5%
495
33%
495
19%
1019
May1st to 15thNight
29%
495
14%
1485
7%
495
36%
495
18%
1035
May16th to endNight
27%
378
10%
1404
9%
377
35%
377
13%
1018
June1st to 15thNight
30%
330
8%
1320
6%
330
38%
330
12%
962
June16th to endNight
44%
330
8%
1320
10%
330
50%
330
20%
850
July1st to 15thNight
46%
310
10%
1240
14%
310
50%
310
20%
789
July16th to endNight
49%
348
10%
1306
10%
326
55%
326
21%
808
August1st to 15thNight
45%
466
14%
1447
10%
464
49%
464
23%
952
August16th to endNight
45%
585
19%
1635
10%
585
50%
585
33%
1023
September1st to 15thNight
42%
660
19%
1730
9%
660
48%
660
33%
1109
September16th to endNight
43%
657
25%
1815
15%
657
52%
657
36%
1069
October1st to 15thNight
34%
660
21%
1864
10%
660
44%
660
25%
1228
October16th to endNight
21%
704
16%
2280
6%
704
33%
704
19%
1511
November1st to 15thNight
31%
700
21%
2277
11%
700
44%
700
21%
1462
November16th to endNight
27%
722
19%
2350
9%
722
39%
722
18%
1536
December1st to 15thNight
19%
750
15%
2688
4%
750
33%
750
15%
1838
December16th to endNight
18%
775
17%
2729
5%
775
34%
775
14%
1890

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%6%25%42445%6%37%
45418
Night
18%7%24424446%38%
45636
TransparencyDay
45%5%11%21%13%1
45106
Night
45%5%11%22%13%1
45466
SeeingDay
22%13%29%20%10%3
5166
Night
22%12%31%25%8%
14295

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
17%5%434245%46%39%
1432
16th to endDay
15%9%25%32445%5%39%
1536
February1st to 15thDay
16%9%26%6%35%5%45%34%
1603
16th to endDay
14%9%46%5%25%5%5%5%35%
1580
March1st to 15thDay
18%9%35%5%3435%6%34%
1823
16th to endDay
15%7%35%5%23445%42%
2042
April1st to 15thDay
18%7%25%435%446%38%
1975
16th to endDay
18%5%245%24446%40%
2145
May1st to 15thDay
24%7%25%424447%32%
2137
16th to endDay
21%5%35%5%245%5%6%34%
2368
June1st to 15thDay
26%7%35%4245%47%27%
2310
16th to endDay
21%6%345%35%5%46%33%
2310
July1st to 15thDay
13%5%25%5%36%6%6%8%34%
2310
16th to endDay
13%5%25%5%46%5%7%9%33%
2458
August1st to 15thDay
15%5%25%435%5%6%8%36%
2159
16th to endDay
12%41442347%8%44%
2213
September1st to 15thDay
15%5%24433236%47%
1900
16th to endDay
14%413423346%51%
1815
October1st to 15thDay
19%6%25%5%23436%40%
1766
16th to endDay
19%6%25%324336%39%
1590
November1st to 15thDay
20%6%1431435%6%40%
1581
16th to endDay
22%5%2431325%443%
1605
December1st to 15thDay
23%8%335%2334436%
1269
16th to endDay
22%12%35%42333433%
1491
January1st to 15thNight
16%8%24324447%40%
2506
16th to endNight
15%9%26%5%2445%5%37%
2688
February1st to 15thNight
13%8%46%7%46%5%45%33%
2257
16th to endNight
16%9%345%35%345%38%
1893
March1st to 15thNight
18%10%35%434445%34%
2114
16th to endNight
17%5%35%324445%44%
1976
April1st to 15thNight
19%7%34435%5%4436%
1643
16th to endNight
21%5%25%434445%36%
1485
May1st to 15thNight
19%7%345%35%45%7%34%
1485
16th to endNight
22%7%46%5%3445%6%28%
1402
June1st to 15thNight
26%6%26%425%347%27%
1320
16th to endNight
19%6%3432346%8%36%
1320
July1st to 15thNight
15%435%5%45%6%6%7%35%
1320
16th to endNight
15%424435%5%5%8%39%
1402
August1st to 15thNight
14%425%5%446%5%8%38%
1457
16th to endNight
13%32432345%9%45%
1635
September1st to 15thNight
15%6%13423346%49%
1730
16th to endNight
14%41332235%6%53%
1815
October1st to 15thNight
19%6%2433345%5%42%
1864
16th to endNight
22%5%25%42335%6%37%
2280
November1st to 15thNight
18%6%23334446%43%
2277
16th to endNight
18%6%24434345%41%
2350
December1st to 15thNight
23%9%25%413345%35%
2688
16th to endNight
22%9%34424435%35%
2729

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
44%6%11%22%13%1
1433
16th to endDay
43%6%12%23%12%1
1536
February1st to 15thDay
51%411%19%11%
1606
16th to endDay
49%5%10%18%13%2
1580
March1st to 15thDay
51%311%18%12%2
1833
16th to endDay
43%48%19%19%4
2042
April1st to 15thDay
47%48%19%17%3
1975
16th to endDay
44%5%10%20%15%4
2145
May1st to 15thDay
50%5%7%18%15%2
2137
16th to endDay
48%7%11%18%12%1
2372
June1st to 15thDay
55%6%11%17%8%
2310
16th to endDay
50%6%9%20%11%
2310
July1st to 15thDay
41%8%13%25%10%
2161
16th to endDay
44%7%15%21%10%
2291
August1st to 15thDay
44%6%15%24%8%
2145
16th to endDay
34%6%15%25%16%1
2213
September1st to 15thDay
38%5%10%27%18%
1900
16th to endDay
32%49%29%21%1
1815
October1st to 15thDay
46%48%24%14%1
1766
16th to endDay
45%411%24%12%1
1590
November1st to 15thDay
44%413%22%13%1
1581
16th to endDay
43%414%19%15%1
1605
December1st to 15thDay
51%412%20%11%
1269
16th to endDay
55%49%16%12%1
1491
January1st to 15thNight
43%5%12%24%11%1
2506
16th to endNight
47%5%9%20%14%2
2688
February1st to 15thNight
51%5%11%19%11%1
2258
16th to endNight
48%49%21%13%2
1893
March1st to 15thNight
51%49%19%12%2
2127
16th to endNight
41%5%10%19%18%4
1976
April1st to 15thNight
48%47%18%17%2
1643
16th to endNight
47%5%9%19%13%3
1485
May1st to 15thNight
47%7%9%18%14%2
1485
16th to endNight
54%6%11%15%10%1
1404
June1st to 15thNight
56%7%11%16%7%1
1320
16th to endNight
44%6%14%20%12%1
1320
July1st to 15thNight
43%6%16%22%10%
1240
16th to endNight
40%7%17%22%10%
1306
August1st to 15thNight
41%7%14%24%10%
1447
16th to endNight
34%7%15%28%14%
1635
September1st to 15thNight
36%5%11%30%15%
1730
16th to endNight
31%410%33%18%1
1815
October1st to 15thNight
42%5%11%24%15%1
1864
16th to endNight
46%412%23%11%1
2280
November1st to 15thNight
43%5%12%22%14%1
2277
16th to endNight
45%412%21%14%1
2350
December1st to 15thNight
50%410%22%11%
2688
16th to endNight
51%5%10%19%12%
2729

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
15%25%36%15%8%
60
16th to endDay
21%28%26%20%3
64
February1st to 15thDay
26%16%34%16%5%
219
16th to endDay
18%20%34%20%5%
239
March1st to 15thDay
28%22%28%15%4
270
16th to endDay
19%24%30%15%6%3
250
April1st to 15thDay
29%14%30%15%6%2
210
16th to endDay
18%17%32%17%9%5%
210
May1st to 15thDay
33%15%22%17%8%2
228
16th to endDay
23%11%34%23%6%
267
June1st to 15thDay
24%18%29%18%9%1
255
16th to endDay
21%5%36%21%11%2
255
July1st to 15thDay
15%5%35%24%14%4
245
16th to endDay
13%6%34%27%14%3
270
August1st to 15thDay
16%8%24%31%15%3
253
16th to endDay
16%6%18%31%17%9%
268
September1st to 15thDay
20%6%23%24%19%6%
255
16th to endDay
18%9%28%17%14%11%
254
October1st to 15thDay
22%14%23%17%17%4
246
16th to endDay
26%13%32%17%9%
240
November1st to 15thDay
25%14%26%21%8%2
235
16th to endDay
29%17%24%21%7%1
240
December1st to 15thDay
27%14%40%10%7%
69
16th to endDay
37%21%28%12%
64
January1st to 15thNight
21%17%33%23%3
720
16th to endNight
22%18%35%19%2
768
February1st to 15thNight
19%17%37%22%2
704
16th to endNight
23%15%34%21%5%
631
March1st to 15thNight
25%17%35%18%2
720
16th to endNight
20%18%32%22%5%
732
April1st to 15thNight
23%17%35%19%4
655
16th to endNight
23%14%32%23%6%
495
May1st to 15thNight
23%10%31%27%6%
495
16th to endNight
26%8%29%29%6%
378
June1st to 15thNight
29%6%27%27%8%
330
16th to endNight
22%324%37%12%
330
July1st to 15thNight
18%124%35%19%
310
16th to endNight
14%225%39%17%
348
August1st to 15thNight
15%325%38%16%
466
16th to endNight
13%428%33%18%2
585
September1st to 15thNight
16%5%28%31%15%2
660
16th to endNight
17%6%28%26%19%1
657
October1st to 15thNight
23%10%26%25%13%1
660
16th to endNight
25%13%34%21%5%
704
November1st to 15thNight
21%10%32%25%8%1
700
16th to endNight
22%15%29%23%7%1
722
December1st to 15thNight
27%13%34%19%4
750
16th to endNight
30%15%31%20%2
775
Page generated at 2017-03-23 07:36:10. Version ac04

Copyright 2017 A. Danko


Greene Clear Sky Chart | Charts Home