Hawkins Pond Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Hawkins Pond Observatory clear sky chart from 2005-11-06 to 2024-03-01.

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
30%
22946
16%
80628
8%
22854
40%
22854
16%
53563

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 10thNight
20%
754
19%
4352
6%
737
36%
737
9%
2574
January11th to 20thNight
20%
758
14%
4374
5%
740
32%
740
6%
2812
January21st to endNight
18%
831
10%
4861
5%
814
33%
814
7%
3410
February1st to 10thNight
16%
760
16%
2490
4%
760
32%
760
13%
1711
February11th to 20thNight
17%
743
20%
2220
5%
740
35%
740
14%
1484
February21st to endNight
20%
628
19%
1884
5%
628
37%
628
16%
1267
March1st to 10thNight
21%
723
19%
2167
7%
723
37%
723
17%
1463
March11th to 20thNight
23%
720
16%
2076
6%
720
34%
720
15%
1450
March21st to endNight
24%
792
21%
2039
7%
792
34%
792
20%
1393
April1st to 10thNight
23%
720
18%
1800
5%
720
31%
720
19%
1295
April11th to 20thNight
26%
685
17%
1749
5%
685
33%
685
21%
1231
April21st to endNight
24%
540
17%
1620
6%
540
33%
540
16%
1112
May1st to 10thNight
28%
540
13%
1620
8%
540
34%
540
17%
1158
May11th to 20thNight
30%
434
18%
1496
11%
434
40%
434
17%
999
May21st to endNight
44%
389
13%
1551
15%
388
50%
388
17%
1006
June1st to 10thNight
39%
360
11%
1440
11%
360
47%
360
14%
975
June11th to 20thNight
40%
360
11%
1440
12%
360
48%
360
17%
936
June21st to endNight
46%
360
11%
1440
13%
360
52%
360
18%
943
July1st to 10thNight
50%
350
13%
1400
17%
350
56%
350
20%
848
July11th to 20thNight
54%
348
13%
1392
18%
348
57%
348
23%
833
July21st to endNight
53%
394
18%
1486
20%
372
59%
372
24%
868
August1st to 10thNight
53%
430
17%
1494
13%
428
57%
428
23%
914
August11th to 20thNight
43%
535
17%
1599
11%
535
46%
535
23%
1059
August21st to endNight
51%
792
19%
1980
9%
792
54%
792
32%
1309
September1st to 10thNight
47%
720
20%
1800
8%
720
53%
720
35%
1150
September11th to 20thNight
47%
720
24%
1966
14%
720
53%
720
32%
1218
September21st to endNight
43%
720
23%
1980
15%
720
50%
720
29%
1267
October1st to 10thNight
39%
720
17%
1980
11%
720
45%
720
20%
1397
October11th to 20thNight
32%
720
18%
2236
8%
720
44%
720
18%
1500
October21st to endNight
26%
792
14%
2574
7%
792
36%
792
14%
1835
November1st to 10thNight
32%
740
21%
2407
11%
740
45%
740
19%
1528
November11th to 20thNight
27%
760
23%
2470
10%
760
42%
760
17%
1586
November21st to endNight
23%
760
17%
2520
6%
760
37%
760
15%
1672
December1st to 10thNight
17%
760
15%
2660
4%
760
29%
760
10%
1887
December11th to 20thNight
18%
760
14%
3231
4%
759
32%
759
10%
2142
December21st to endNight
18%
828
11%
4834
3%
817
32%
817
6%
3331

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
17%7%36%5%35%5%6%7%36%
78329
Night
17%7%35%5%35%5%5%7%37%
81073
TransparencyDay
45%7%12%21%13%2
78034
Night
46%7%12%21%12%2
80902
SeeingDay
23%17%28%20%9%3
13913
Night
22%15%27%26%9%1
22967

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 10thDay
14%8%36%6%445%5%7%38%
2517
11th to 20thDay
16%9%48%7%46%5%6%7%28%
2520
21st to endDay
16%10%38%6%45%6%6%6%30%
2772
February1st to 10thDay
15%9%46%6%46%6%5%7%34%
1686
11th to 20thDay
11%9%47%7%35%5%6%7%36%
1848
21st to endDay
16%10%46%6%35%45%5%35%
1570
March1st to 10thDay
14%8%35%8%36%5%5%7%37%
1797
11th to 20thDay
16%9%36%4345%6%7%36%
1882
21st to endDay
15%8%46%6%4445%6%38%
2314
April1st to 10thDay
19%9%36%5%35%45%7%35%
2160
11th to 20thDay
17%5%35%5%346%5%7%39%
2159
21st to endDay
22%8%26%6%445%5%5%32%
2340
May1st to 10thDay
23%7%37%6%35%445%32%
2340
11th to 20thDay
19%6%36%43446%7%38%
2414
21st to endDay
16%5%36%5%35%5%6%8%38%
2725
June1st to 10thDay
21%6%36%5%46%6%6%8%29%
2520
11th to 20thDay
17%5%25%6%45%5%6%8%37%
2520
21st to endDay
18%7%26%6%46%6%6%8%31%
2520
July1st to 10thDay
16%6%25%5%36%6%7%7%37%
2520
11th to 20thDay
12%6%36%6%46%7%6%9%36%
2520
21st to endDay
14%5%35%6%46%5%7%8%38%
2744
August1st to 10thDay
12%5%35%6%46%6%7%8%38%
2414
11th to 20thDay
14%5%35%7%35%6%8%10%35%
2299
21st to endDay
13%3145%35%5%5%10%46%
2376
September1st to 10thDay
12%325%5%35%5%6%9%45%
2160
11th to 20thDay
15%424424435%53%
1994
21st to endDay
15%5%13435%46%6%47%
1980
October1st to 10thDay
23%7%35%435%45%5%36%
1980
11th to 20thDay
17%6%245%35%5%5%7%40%
1719
21st to endDay
26%8%35%4445%46%31%
1782
November1st to 10thDay
15%5%26%5%3445%9%42%
1671
11th to 20thDay
19%5%25%5%25%5%6%8%38%
1710
21st to endDay
22%6%25%5%25%5%6%6%36%
1658
December1st to 10thDay
20%9%37%6%45%6%6%6%29%
1520
11th to 20thDay
22%7%25%5%33446%39%
1906
21st to endDay
25%10%35%5%35%45%6%29%
2772
January1st to 10thNight
17%8%25%5%35%5%5%7%38%
4429
11th to 20thNight
13%8%49%8%45%7%6%7%28%
4440
21st to endNight
18%12%5%8%6%345%5%6%29%
4884
February1st to 10thNight
14%9%36%6%45%6%6%8%33%
2490
11th to 20thNight
11%9%36%5%36%6%6%8%37%
2218
21st to endNight
15%7%36%6%45%46%8%37%
1884
March1st to 10thNight
15%9%25%5%45%5%6%6%38%
2157
11th to 20thNight
17%8%36%5%46%6%6%6%35%
2076
21st to endNight
16%8%36%5%2445%6%41%
2039
April1st to 10thNight
20%8%35%5%3445%6%36%
1800
11th to 20thNight
20%5%35%5%3446%6%38%
1749
21st to endNight
23%7%245%25%35%7%36%
1620
May1st to 10thNight
22%8%46%5%35%45%6%33%
1620
11th to 20thNight
19%6%36%5%345%5%7%37%
1495
21st to endNight
17%6%35%5%45%46%7%39%
1550
June1st to 10thNight
20%7%35%435%5%6%7%34%
1440
11th to 20thNight
20%6%25%435%5%5%7%39%
1440
21st to endNight
17%5%35%5%35%5%5%8%37%
1440
July1st to 10thNight
17%4344345%6%9%42%
1440
11th to 20thNight
14%5%25%5%346%6%9%42%
1440
21st to endNight
14%5%245%3447%8%44%
1574
August1st to 10thNight
15%425%5%3446%8%45%
1504
11th to 20thNight
15%7%35%5%345%6%7%40%
1599
21st to endNight
16%4244345%48%47%
1980
September1st to 10thNight
12%5%245%3345%7%51%
1800
11th to 20thNight
15%5%14433446%51%
1966
21st to endNight
16%4244345%6%6%46%
1980
October1st to 10thNight
21%6%35%435%446%39%
1980
11th to 20thNight
17%6%25%5%35%5%6%8%37%
2236
21st to endNight
24%8%25%5%3446%6%33%
2574
November1st to 10thNight
16%5%25%5%35%5%5%7%42%
2407
11th to 20thNight
17%6%25%5%345%5%7%40%
2470
21st to endNight
17%6%246%45%5%5%7%38%
2520
December1st to 10thNight
21%9%36%7%35%46%6%31%
2660
11th to 20thNight
20%9%35%4245%6%7%36%
3288
21st to endNight
24%11%36%5%345%45%30%
4884

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 10thDay
43%6%13%28%10%1
2518
11th to 20thDay
50%9%14%19%6%1
2520
21st to endDay
50%10%10%19%9%1
2772
February1st to 10thDay
49%7%12%20%10%2
1686
11th to 20thDay
47%7%11%19%13%3
1857
21st to endDay
50%6%12%17%12%3
1570
March1st to 10thDay
48%5%13%18%12%4
1800
11th to 20thDay
45%5%14%15%16%4
1882
21st to endDay
47%5%10%17%17%4
2314
April1st to 10thDay
48%5%9%20%14%4
2160
11th to 20thDay
43%7%12%20%16%2
2159
21st to endDay
54%410%16%13%3
2340
May1st to 10thDay
53%6%7%20%12%2
2340
11th to 20thDay
45%6%9%21%17%2
2418
21st to endDay
44%8%13%21%12%2
2725
June1st to 10thDay
50%8%12%19%10%1
2520
11th to 20thDay
44%7%11%20%15%3
2520
21st to endDay
48%9%12%18%11%1
2520
July1st to 10thDay
42%8%12%22%16%1
2450
11th to 20thDay
42%9%13%25%10%1
2445
21st to endDay
41%8%15%23%13%1
2591
August1st to 10thDay
40%10%14%22%12%1
2400
11th to 20thDay
40%10%15%23%11%1
2299
21st to endDay
34%7%15%24%18%1
2376
September1st to 10thDay
34%8%14%27%15%1
2160
11th to 20thDay
35%5%10%27%22%2
1994
21st to endDay
37%6%13%25%18%2
1980
October1st to 10thDay
49%7%9%20%13%2
1980
11th to 20thDay
41%7%15%26%9%1
1719
21st to endDay
53%7%10%18%10%2
1782
November1st to 10thDay
39%5%16%23%15%2
1671
11th to 20thDay
43%5%14%18%17%2
1710
21st to endDay
47%7%17%18%9%1
1658
December1st to 10thDay
53%8%14%16%9%1
1520
11th to 20thDay
48%6%11%17%17%2
1906
21st to endDay
57%6%9%17%10%
2772
January1st to 10thNight
43%7%14%24%10%2
4429
11th to 20thNight
49%8%16%16%9%2
4440
21st to endNight
55%7%11%17%9%1
4884
February1st to 10thNight
47%7%12%19%12%2
2490
11th to 20thNight
43%7%11%22%15%2
2220
21st to endNight
44%7%12%22%11%4
1884
March1st to 10thNight
44%6%11%22%14%3
2167
11th to 20thNight
47%7%11%18%13%4
2077
21st to endNight
44%5%11%17%19%5%
2039
April1st to 10thNight
48%5%10%19%15%2
1800
11th to 20thNight
47%5%9%22%16%1
1749
21st to endNight
49%5%11%18%14%3
1620
May1st to 10thNight
52%5%9%20%13%2
1620
11th to 20thNight
45%8%10%19%15%3
1496
21st to endNight
45%8%13%22%11%2
1551
June1st to 10thNight
49%8%12%18%12%
1440
11th to 20thNight
46%7%13%19%13%2
1440
21st to endNight
43%10%14%21%11%1
1440
July1st to 10thNight
38%10%15%22%14%1
1400
11th to 20thNight
37%9%16%25%13%
1392
21st to endNight
36%8%14%29%13%1
1486
August1st to 10thNight
37%9%13%26%13%1
1494
11th to 20thNight
42%8%16%22%12%
1599
21st to endNight
37%7%13%27%17%
1980
September1st to 10thNight
33%7%13%29%17%1
1800
11th to 20thNight
34%6%11%28%20%2
1966
21st to endNight
37%7%12%27%16%1
1980
October1st to 10thNight
47%7%11%22%12%2
1980
11th to 20thNight
44%8%13%26%9%1
2236
21st to endNight
51%6%11%19%11%2
2574
November1st to 10thNight
40%8%12%23%15%2
2407
11th to 20thNight
43%5%12%22%15%2
2470
21st to endNight
45%7%16%22%9%1
2520
December1st to 10thNight
53%7%12%20%8%
2660
11th to 20thNight
48%7%14%15%15%1
3288
21st to endNight
57%411%20%8%1
4884

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 10thDay
28%20%31%18%31
180
11th to 20thDay
33%20%31%13%22
180
21st to endDay
19%26%29%21%6%
198
February1st to 10thDay
30%24%28%16%3
298
11th to 20thDay
24%29%31%12%3
456
21st to endDay
29%24%26%18%2
382
March1st to 10thDay
28%18%35%15%4
420
11th to 20thDay
29%26%26%12%5%1
420
21st to endDay
26%22%26%17%6%3
462
April1st to 10thDay
30%21%25%15%6%2
420
11th to 20thDay
27%24%23%18%7%2
412
21st to endDay
32%20%26%14%6%2
420
May1st to 10thDay
30%22%26%14%5%3
423
11th to 20thDay
22%18%33%19%6%2
447
21st to endDay
21%11%33%22%9%3
485
June1st to 10thDay
20%14%36%18%11%2
450
11th to 20thDay
17%16%31%22%11%3
450
21st to endDay
18%13%32%22%12%3
450
July1st to 10thDay
19%9%29%24%14%4
445
11th to 20thDay
16%7%29%32%14%3
444
21st to endDay
13%9%36%26%12%4
488
August1st to 10thDay
12%12%27%27%18%4
446
11th to 20thDay
17%10%28%22%17%6%
439
21st to endDay
14%10%27%27%16%6%
495
September1st to 10thDay
16%11%25%23%18%7%
450
11th to 20thDay
18%12%26%21%14%10%
450
21st to endDay
14%17%27%23%13%6%
450
October1st to 10thDay
27%14%20%21%13%4
450
11th to 20thDay
22%17%23%23%12%2
396
21st to endDay
38%15%21%20%6%1
396
November1st to 10thDay
24%14%26%25%9%1
365
11th to 20thDay
30%19%24%19%6%1
370
21st to endDay
30%22%25%16%6%1
318
December1st to 10thDay
26%25%26%19%4
180
11th to 20thDay
33%20%33%11%3
180
21st to endDay
31%22%27%15%5%1
198
January1st to 10thNight
21%21%32%24%3
760
11th to 20thNight
27%18%28%24%3
760
21st to endNight
19%23%32%22%4
836
February1st to 10thNight
21%20%34%23%2
760
11th to 20thNight
20%24%33%20%3
743
21st to endNight
22%20%31%21%5%
628
March1st to 10thNight
27%16%30%23%3
723
11th to 20thNight
23%20%28%23%5%1
720
21st to endNight
23%20%28%21%8%1
792
April1st to 10thNight
25%18%28%24%5%
720
11th to 20thNight
23%16%29%24%7%
685
21st to endNight
27%16%27%24%6%
540
May1st to 10thNight
27%12%26%27%8%
540
11th to 20thNight
21%13%29%28%9%
434
21st to endNight
19%10%21%37%13%1
389
June1st to 10thNight
20%8%25%34%11%2
360
11th to 20thNight
21%8%24%32%14%
360
21st to endNight
21%424%39%13%1
360
July1st to 10thNight
14%5%22%41%17%
350
11th to 20thNight
16%221%39%20%2
348
21st to endNight
15%421%41%18%2
394
August1st to 10thNight
16%421%39%20%
430
11th to 20thNight
17%7%25%31%17%3
535
21st to endNight
16%5%21%33%21%3
792
September1st to 10thNight
13%6%27%32%20%2
720
11th to 20thNight
16%8%23%29%18%5%
720
21st to endNight
18%11%23%29%17%3
720
October1st to 10thNight
25%11%19%28%14%2
720
11th to 20thNight
20%16%26%25%12%1
720
21st to endNight
29%16%23%24%8%
792
November1st to 10thNight
18%16%27%28%9%1
740
11th to 20thNight
22%21%26%23%7%1
760
21st to endNight
23%20%28%24%5%1
760
December1st to 10thNight
26%21%28%19%5%
760
11th to 20thNight
26%21%28%21%3
760
21st to endNight
29%21%25%22%3
836
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