Warwick
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Warwick clear sky chart from 2005-11-06 to 2024-02-25.

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%
23186
18%
80419
8%
23099
40%
23099
18%
52236

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
15%
751
24%
4325
6%
737
35%
737
12%
2262
January11th to 20thNight
14%
759
22%
4340
3%
740
31%
740
8%
2591
January21st to endNight
16%
830
12%
4862
6%
814
35%
814
8%
3454
February1st to 10thNight
16%
760
18%
2355
4%
760
33%
760
17%
1567
February11th to 20thNight
11%
743
20%
2220
4%
740
30%
740
17%
1482
February21st to endNight
15%
611
23%
1831
6%
611
34%
611
17%
1226
March1st to 10thNight
21%
720
21%
2160
8%
720
38%
720
21%
1399
March11th to 20thNight
21%
720
18%
2066
6%
720
34%
720
20%
1407
March21st to endNight
19%
792
22%
2056
6%
792
32%
792
22%
1416
April1st to 10thNight
22%
720
19%
1800
5%
720
30%
720
21%
1269
April11th to 20thNight
24%
711
17%
1775
3%
711
31%
711
24%
1242
April21st to endNight
21%
544
19%
1624
6%
544
30%
544
19%
1113
May1st to 10thNight
25%
540
12%
1620
6%
540
31%
540
15%
1196
May11th to 20thNight
21%
532
16%
1594
6%
532
30%
532
19%
1106
May21st to endNight
38%
397
10%
1560
10%
397
42%
397
14%
1077
June1st to 10thNight
40%
360
13%
1440
13%
360
47%
360
16%
945
June11th to 20thNight
39%
360
14%
1440
15%
360
47%
360
18%
912
June21st to endNight
47%
360
12%
1440
12%
360
54%
360
20%
889
July1st to 10thNight
45%
350
11%
1400
15%
350
49%
350
18%
901
July11th to 20thNight
54%
348
12%
1392
15%
348
56%
348
19%
889
July21st to endNight
49%
394
16%
1486
17%
372
54%
372
21%
909
August1st to 10thNight
49%
510
15%
1574
12%
508
50%
508
26%
1008
August11th to 20thNight
49%
583
15%
1647
10%
583
51%
583
25%
1119
August21st to endNight
53%
792
20%
1980
10%
792
56%
792
34%
1295
September1st to 10thNight
43%
720
18%
1804
8%
720
48%
720
28%
1253
September11th to 20thNight
45%
720
22%
1980
13%
720
52%
720
33%
1228
September21st to endNight
39%
720
21%
1980
13%
720
47%
720
25%
1367
October1st to 10thNight
35%
720
17%
1980
9%
720
42%
720
22%
1373
October11th to 20thNight
33%
720
22%
2177
9%
720
47%
720
26%
1357
October21st to endNight
22%
792
17%
2574
6%
792
36%
792
20%
1699
November1st to 10thNight
32%
740
21%
2407
10%
740
46%
740
23%
1482
November11th to 20thNight
21%
760
23%
2470
9%
760
38%
760
19%
1559
November21st to endNight
24%
760
22%
2470
8%
760
42%
760
21%
1508
December1st to 10thNight
19%
760
19%
2588
5%
760
35%
760
16%
1698
December11th to 20thNight
17%
760
19%
3196
4%
759
34%
759
13%
1954
December21st to endNight
15%
827
14%
4806
4%
817
35%
817
9%
3084

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%6%35%5%3445%7%41%
78299
Night
17%7%35%5%3445%6%41%
80986
TransparencyDay
42%7%12%21%15%2
78004
Night
44%6%12%21%14%2
80815
SeeingDay
19%16%33%22%8%2
14127
Night
20%14%33%25%7%1
23212

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%7%35%43445%5%46%
2517
11th to 20thDay
17%7%36%6%35%445%40%
2520
21st to endDay
22%11%46%5%33345%35%
2772
February1st to 10thDay
18%8%25%335%5%6%6%38%
1818
11th to 20thDay
14%7%345%345%47%43%
1848
21st to endDay
21%7%35%425%5%45%39%
1520
March1st to 10thDay
15%6%25%44445%8%43%
1797
11th to 20thDay
17%5%344345%6%8%40%
1894
21st to endDay
18%8%36%5%33445%41%
2297
April1st to 10thDay
18%7%35%43346%7%39%
2160
11th to 20thDay
18%6%34425%45%7%42%
2134
21st to endDay
21%6%25%5%3445%6%38%
2335
May1st to 10thDay
24%8%36%434447%34%
2340
11th to 20thDay
18%6%25%5%3445%7%41%
2306
21st to endDay
14%6%25%4345%48%44%
2725
June1st to 10thDay
18%6%35%5%35%5%6%9%34%
2520
11th to 20thDay
15%6%35%5%36%6%7%8%37%
2520
21st to endDay
14%6%35%5%35%5%6%10%39%
2520
July1st to 10thDay
13%5%35%5%36%5%6%9%41%
2520
11th to 20thDay
14%5%25%6%35%5%6%10%39%
2520
21st to endDay
12%5%35%6%35%6%7%9%38%
2744
August1st to 10thDay
11%5%35%5%35%6%7%10%38%
2335
11th to 20thDay
13%5%36%6%45%5%6%8%39%
2250
21st to endDay
12%5%25%5%46%5%6%7%43%
2376
September1st to 10thDay
15%5%35%4345%5%6%44%
2156
11th to 20thDay
13%6%24432446%52%
1980
21st to endDay
19%5%24423445%45%
1980
October1st to 10thDay
24%6%24433345%42%
1980
11th to 20thDay
16%5%2442345%7%47%
1777
21st to endDay
20%5%25%5%3445%5%43%
1782
November1st to 10thDay
16%6%24424445%47%
1671
11th to 20thDay
18%5%2433445%7%45%
1710
21st to endDay
17%5%35%424445%46%
1710
December1st to 10thDay
18%7%35%425%45%7%39%
1587
11th to 20thDay
21%6%34423335%46%
1906
21st to endDay
20%9%36%5%35%345%36%
2772
January1st to 10thNight
17%6%24324345%49%
4429
11th to 20thNight
17%9%47%5%3344441%
4440
21st to endNight
22%11%47%5%3444432%
4884
February1st to 10thNight
17%9%35%6%345%45%42%
2355
11th to 20thNight
16%7%35%5%3445%6%41%
2218
21st to endNight
17%7%35%5%3445%442%
1831
March1st to 10thNight
16%6%3444445%8%43%
2150
11th to 20thNight
16%8%25%6%4445%7%39%
2065
21st to endNight
18%9%35%5%23346%41%
2056
April1st to 10thNight
18%8%35%5%35%45%6%39%
1800
11th to 20thNight
19%6%35%5%3445%7%40%
1775
21st to endNight
21%7%36%5%33345%40%
1624
May1st to 10thNight
23%7%36%6%25%446%33%
1620
11th to 20thNight
20%5%35%7%3445%7%38%
1593
21st to endNight
17%7%36%6%35%45%8%36%
1559
June1st to 10thNight
18%6%36%6%345%5%7%38%
1440
11th to 20thNight
18%6%35%5%3446%8%39%
1440
21st to endNight
15%7%25%42446%10%41%
1440
July1st to 10thNight
13%6%36%5%35%6%7%8%38%
1440
11th to 20thNight
15%6%25%5%35%6%7%10%37%
1440
21st to endNight
12%5%36%6%45%47%9%40%
1574
August1st to 10thNight
9%6%35%6%36%5%7%9%41%
1584
11th to 20thNight
10%6%25%6%45%7%6%9%38%
1647
21st to endNight
13%6%2443445%8%48%
1980
September1st to 10thNight
13%5%36%5%345%5%6%42%
1804
11th to 20thNight
14%6%24423347%51%
1980
21st to endNight
18%7%345%25%445%43%
1980
October1st to 10thNight
21%6%25%434345%42%
1980
11th to 20thNight
16%4245%345%47%47%
2177
21st to endNight
21%6%345%3435%7%40%
2574
November1st to 10thNight
14%5%25%434445%48%
2407
11th to 20thNight
18%7%25%424336%46%
2470
21st to endNight
16%6%2433445%7%47%
2470
December1st to 10thNight
20%7%35%5%2445%5%41%
2588
11th to 20thNight
19%6%25%42435%6%44%
3288
21st to endNight
20%11%46%5%24345%38%
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
39%6%9%28%14%2
2518
11th to 20thDay
45%8%10%24%12%2
2520
21st to endDay
52%5%8%21%12%1
2772
February1st to 10thDay
45%6%14%19%14%3
1818
11th to 20thDay
41%6%11%23%15%3
1857
21st to endDay
47%6%12%19%14%3
1520
March1st to 10thDay
41%5%13%23%14%5%
1800
11th to 20thDay
40%5%13%23%15%3
1894
21st to endDay
46%6%10%17%17%5%
2297
April1st to 10thDay
42%8%12%19%16%3
2160
11th to 20thDay
42%6%9%22%18%3
2134
21st to endDay
46%8%10%19%14%4
2335
May1st to 10thDay
50%7%10%18%12%3
2340
11th to 20thDay
42%8%10%20%16%3
2310
21st to endDay
39%9%16%20%13%2
2725
June1st to 10thDay
44%10%15%20%10%1
2520
11th to 20thDay
42%9%14%20%13%1
2520
21st to endDay
39%10%15%22%12%1
2520
July1st to 10thDay
39%9%14%21%14%2
2450
11th to 20thDay
38%9%15%26%10%2
2445
21st to endDay
37%10%16%19%15%3
2591
August1st to 10thDay
38%10%17%22%13%1
2321
11th to 20thDay
39%11%14%23%12%1
2250
21st to endDay
37%10%13%20%18%2
2376
September1st to 10thDay
38%8%12%22%18%1
2156
11th to 20thDay
32%7%13%23%22%3
1980
21st to endDay
42%6%9%20%21%2
1980
October1st to 10thDay
44%6%10%20%16%3
1980
11th to 20thDay
36%6%13%27%16%1
1777
21st to endDay
43%5%13%21%15%4
1782
November1st to 10thDay
39%7%13%20%19%2
1671
11th to 20thDay
39%5%12%21%20%3
1710
21st to endDay
41%5%11%27%12%3
1710
December1st to 10thDay
46%6%13%16%17%2
1587
11th to 20thDay
43%414%17%17%6%
1906
21st to endDay
49%8%12%20%10%1
2772
January1st to 10thNight
37%5%12%31%12%3
4429
11th to 20thNight
46%5%12%22%12%3
4440
21st to endNight
55%7%9%17%11%2
4884
February1st to 10thNight
46%5%13%22%13%2
2355
11th to 20thNight
45%5%10%19%17%4
2220
21st to endNight
45%5%9%22%15%4
1831
March1st to 10thNight
41%6%12%21%16%4
2160
11th to 20thNight
45%6%11%18%17%4
2066
21st to endNight
45%5%9%18%18%6%
2056
April1st to 10thNight
47%5%10%19%16%3
1800
11th to 20thNight
44%6%11%18%19%3
1775
21st to endNight
48%5%10%19%13%5%
1624
May1st to 10thNight
53%7%10%15%12%2
1620
11th to 20thNight
47%7%12%18%13%3
1594
21st to endNight
48%11%14%16%11%1
1560
June1st to 10thNight
46%9%12%19%13%1
1440
11th to 20thNight
45%6%12%23%13%1
1440
21st to endNight
41%8%15%24%11%1
1440
July1st to 10thNight
44%9%14%20%12%1
1400
11th to 20thNight
40%11%15%24%9%1
1392
21st to endNight
39%9%16%23%11%2
1486
August1st to 10thNight
36%11%17%23%11%2
1574
11th to 20thNight
39%11%15%23%11%
1647
21st to endNight
34%8%13%24%19%2
1980
September1st to 10thNight
42%8%11%22%16%2
1804
11th to 20thNight
34%6%12%22%24%2
1980
21st to endNight
44%7%8%18%20%3
1980
October1st to 10thNight
46%6%11%19%14%4
1980
11th to 20thNight
37%7%14%27%15%1
2177
21st to endNight
45%5%13%21%14%2
2574
November1st to 10thNight
39%6%13%21%18%4
2407
11th to 20thNight
42%5%10%23%18%3
2470
21st to endNight
38%5%14%27%13%2
2470
December1st to 10thNight
46%6%13%20%15%1
2588
11th to 20thNight
42%6%13%19%17%2
3288
21st to endNight
49%6%11%22%12%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
21%25%33%17%4
180
11th to 20thDay
21%31%34%11%4
180
21st to endDay
19%26%37%13%41
198
February1st to 10thDay
25%23%35%15%1
403
11th to 20thDay
25%25%39%10%2
456
21st to endDay
23%24%36%14%3
362
March1st to 10thDay
22%22%35%19%2
420
11th to 20thDay
22%23%37%15%21
420
21st to endDay
24%19%37%12%6%2
462
April1st to 10thDay
24%24%31%15%6%
420
11th to 20thDay
22%22%36%16%4
412
21st to endDay
26%19%34%15%42
420
May1st to 10thDay
29%18%33%15%4
423
11th to 20thDay
20%17%41%17%5%1
447
21st to endDay
17%10%34%29%8%2
485
June1st to 10thDay
17%11%36%25%9%2
450
11th to 20thDay
15%14%37%26%7%1
450
21st to endDay
15%11%35%30%7%1
450
July1st to 10thDay
16%7%28%34%14%1
445
11th to 20thDay
12%7%27%37%16%2
444
21st to endDay
13%7%35%34%9%1
488
August1st to 10thDay
11%8%32%35%11%3
446
11th to 20thDay
16%6%27%33%15%3
439
21st to endDay
12%6%33%29%13%7%
495
September1st to 10thDay
17%10%26%28%15%4
450
11th to 20thDay
14%10%30%26%14%6%
450
21st to endDay
21%10%33%24%9%3
450
October1st to 10thDay
25%12%27%21%11%5%
450
11th to 20thDay
17%17%29%23%11%1
406
21st to endDay
23%17%31%19%9%1
396
November1st to 10thDay
15%17%35%22%8%2
365
11th to 20thDay
22%24%30%18%5%
370
21st to endDay
21%21%31%19%7%1
370
December1st to 10thDay
23%21%35%17%4
247
11th to 20thDay
28%25%33%11%3
180
21st to endDay
21%21%39%13%6%2
198
January1st to 10thNight
20%21%39%17%3
760
11th to 20thNight
27%22%34%15%3
760
21st to endNight
19%24%36%18%3
836
February1st to 10thNight
21%19%38%20%1
760
11th to 20thNight
23%22%41%12%1
743
21st to endNight
23%22%36%17%2
611
March1st to 10thNight
22%19%37%19%4
720
11th to 20thNight
21%15%40%20%3
720
21st to endNight
23%16%38%19%41
792
April1st to 10thNight
23%18%35%21%4
720
11th to 20thNight
20%14%39%22%5%
711
21st to endNight
24%15%35%21%5%
544
May1st to 10thNight
26%11%32%25%6%
540
11th to 20thNight
21%12%40%22%41
532
21st to endNight
22%5%27%36%9%1
398
June1st to 10thNight
20%7%28%36%9%1
360
11th to 20thNight
19%6%28%37%9%
360
21st to endNight
18%5%27%40%10%
360
July1st to 10thNight
15%5%27%38%14%1
350
11th to 20thNight
15%422%44%14%1
348
21st to endNight
14%227%42%14%1
394
August1st to 10thNight
11%428%44%12%
510
11th to 20thNight
12%427%39%18%1
583
21st to endNight
15%421%38%19%3
792
September1st to 10thNight
16%428%34%15%2
720
11th to 20thNight
16%6%27%31%17%3
720
21st to endNight
22%7%26%29%14%2
720
October1st to 10thNight
24%10%28%24%12%2
720
11th to 20thNight
18%11%33%25%11%2
720
21st to endNight
22%13%38%20%7%
792
November1st to 10thNight
17%13%34%24%11%1
740
11th to 20thNight
21%19%34%18%6%
760
21st to endNight
19%21%33%21%6%1
760
December1st to 10thNight
25%18%33%20%41
760
11th to 20thNight
21%22%36%17%31
760
21st to endNight
23%20%37%17%3
836
Page generated at 2024-02-22 06:05:45. Version ac07

Copyright 2024 Attilla Danko


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