Clarenville
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Clarenville clear sky chart from 2005-11-06 to 2024-01-22.

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 Type	Minimum conditions for hour to be usable				Out of hours
	Clear of Clouds	Transparency	Seeing	Sky Brightness
Planetary:	50%	(no limit)	Average	(no limit)	Nighttime Hours
Deep Sky:	70%	Average	(no limit)	5.9	Nighttime Hours
CCD Imaging:	70%	Below Average	Poor	(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

By Month

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 Forecast	Data Points
Cloud Cover	Day	21% 13% 5% 8% 7% 4 5% 5% 5% 6% 23%	74674
	Night	20% 13% 5% 8% 6% 3 5% 4 5% 6% 25%	75270
Transparency	Day	62% 7% 11% 13% 6% 1	74365
	Night	60% 7% 11% 14% 7% 1	75114
Seeing	Day	26% 15% 31% 20% 7% 1	16972
	Night	26% 14% 32% 22% 5%	23775

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
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	17% 16% 7% 9% 7% 4 4 5% 4 6% 22%	1326
	11th to 20th	Day	17% 14% 5% 9% 7% 4 5% 4 4 5% 26%	1505
	21st to end	Day	17% 15% 6% 10% 8% 4 6% 4 4 6% 22%	1593
February	1st to 10th	Day	16% 13% 4 9% 8% 4 5% 6% 4 6% 23%	1509
	11th to 20th	Day	19% 13% 3 10% 9% 5% 6% 5% 5% 6% 19%	1605
	21st to end	Day	13% 12% 5% 10% 9% 5% 5% 5% 5% 7% 23%	1480
March	1st to 10th	Day	17% 15% 6% 8% 7% 4 6% 5% 4 5% 24%	1796
	11th to 20th	Day	17% 15% 6% 8% 8% 4 6% 5% 4 6% 21%	1966
	21st to end	Day	21% 21% 6% 9% 7% 4 5% 4 3 4 17%	2200
April	1st to 10th	Day	19% 14% 6% 9% 7% 4 5% 5% 5% 6% 19%	2173
	11th to 20th	Day	22% 15% 5% 9% 6% 3 5% 4 4 5% 22%	2311
	21st to end	Day	22% 19% 6% 8% 7% 3 4 4 4 5% 18%	2340
May	1st to 10th	Day	22% 17% 6% 10% 8% 3 4 4 4 5% 18%	2340
	11th to 20th	Day	22% 14% 5% 8% 7% 4 5% 4 4 6% 21%	2546
	21st to end	Day	22% 13% 4 7% 6% 3 5% 5% 5% 7% 22%	2918
June	1st to 10th	Day	30% 13% 5% 8% 6% 4 5% 4 4 5% 17%	2700
	11th to 20th	Day	27% 12% 4 7% 7% 3 5% 4 4 7% 21%	2700
	21st to end	Day	22% 10% 4 8% 7% 4 5% 5% 5% 7% 23%	2700
July	1st to 10th	Day	21% 9% 4 6% 7% 4 5% 5% 5% 7% 26%	2700
	11th to 20th	Day	17% 9% 4 8% 7% 4 6% 6% 6% 7% 25%	2676
	21st to end	Day	21% 9% 5% 7% 8% 4 6% 6% 6% 7% 21%	2745
August	1st to 10th	Day	25% 8% 3 7% 7% 3 6% 5% 7% 6% 22%	2431
	11th to 20th	Day	23% 9% 4 8% 6% 3 5% 5% 5% 6% 24%	2305
	21st to end	Day	19% 9% 4 7% 7% 4 6% 5% 6% 8% 26%	2574
September	1st to 10th	Day	18% 8% 3 8% 7% 3 5% 4 6% 6% 31%	2154
	11th to 20th	Day	25% 9% 3 5% 6% 3 4 3 4 7% 30%	1980
	21st to end	Day	17% 9% 4 8% 6% 3 4 4 4 8% 33%	1980
October	1st to 10th	Day	19% 11% 3 6% 5% 4 4 4 5% 6% 33%	1909
	11th to 20th	Day	23% 14% 3 8% 6% 4 4 4 4 5% 24%	1715
	21st to end	Day	23% 13% 4 8% 7% 4 5% 5% 5% 5% 21%	1782
November	1st to 10th	Day	22% 11% 4 7% 6% 3 4 5% 5% 6% 26%	1658
	11th to 20th	Day	21% 13% 5% 8% 6% 3 5% 3 4 6% 24%	1520
	21st to end	Day	23% 14% 5% 7% 6% 3 5% 5% 4 5% 24%	1397
December	1st to 10th	Day	21% 16% 5% 10% 5% 3 5% 5% 5% 6% 20%	1330
	11th to 20th	Day	17% 15% 7% 10% 8% 4 5% 5% 4 5% 21%	1668
	21st to end	Day	20% 18% 7% 9% 6% 3 4 5% 4 5% 18%	2442
January	1st to 10th	Night	18% 13% 5% 9% 7% 3 5% 4 5% 6% 23%	2839
	11th to 20th	Night	17% 14% 5% 9% 6% 3 5% 5% 5% 6% 25%	2672
	21st to end	Night	17% 12% 5% 8% 6% 4 5% 5% 5% 6% 27%	2797
February	1st to 10th	Night	16% 11% 5% 9% 7% 4 5% 5% 4 7% 27%	2449
	11th to 20th	Night	19% 13% 6% 9% 7% 3 5% 4 5% 6% 22%	2241
	21st to end	Night	10% 14% 7% 9% 7% 4 5% 4 5% 6% 29%	1776
March	1st to 10th	Night	18% 12% 6% 9% 5% 3 5% 5% 5% 5% 27%	2151
	11th to 20th	Night	14% 13% 5% 9% 8% 4 6% 6% 6% 6% 23%	1993
	21st to end	Night	22% 18% 6% 9% 7% 3 4 4 4 4 21%	2154
April	1st to 10th	Night	23% 14% 6% 7% 6% 3 4 3 5% 5% 26%	1787
	11th to 20th	Night	23% 14% 6% 6% 6% 3 4 4 5% 5% 25%	1598
	21st to end	Night	24% 19% 6% 6% 4 3 3 3 4 6% 23%	1620
May	1st to 10th	Night	23% 15% 6% 7% 6% 4 6% 4 5% 6% 18%	1620
	11th to 20th	Night	23% 12% 4 6% 6% 3 5% 4 5% 7% 25%	1345
	21st to end	Night	26% 12% 3 7% 6% 3 5% 5% 5% 6% 23%	1356
June	1st to 10th	Night	28% 12% 5% 7% 5% 4 5% 4 4 4 20%	1260
	11th to 20th	Night	26% 10% 4 7% 7% 4 5% 4 4 6% 23%	1260
	21st to end	Night	23% 11% 4 7% 6% 3 5% 5% 5% 9% 22%	1260
July	1st to 10th	Night	19% 9% 3 7% 5% 4 5% 5% 6% 9% 25%	1260
	11th to 20th	Night	19% 8% 4 7% 7% 4 5% 4 5% 8% 28%	1281
	21st to end	Night	21% 9% 3 7% 7% 4 5% 5% 6% 7% 25%	1573
August	1st to 10th	Night	21% 9% 3 6% 6% 3 5% 5% 6% 9% 26%	1506
	11th to 20th	Night	21% 9% 4 7% 5% 3 4 4 5% 7% 30%	1595
	21st to end	Night	19% 7% 3 5% 5% 3 5% 5% 6% 7% 34%	1782
September	1st to 10th	Night	19% 8% 3 6% 5% 3 4 4 6% 8% 34%	1801
	11th to 20th	Night	23% 9% 3 6% 4 3 5% 4 4 6% 32%	1980
	21st to end	Night	20% 11% 3 6% 4 3 3 4 5% 7% 33%	1980
October	1st to 10th	Night	20% 11% 3 6% 5% 3 4 4 6% 7% 31%	2050
	11th to 20th	Night	22% 13% 3 6% 6% 3 4 5% 5% 7% 26%	2244
	21st to end	Night	23% 14% 3 7% 6% 3 5% 4 4 6% 25%	2574
November	1st to 10th	Night	20% 12% 5% 7% 6% 3 6% 5% 5% 6% 26%	2417
	11th to 20th	Night	23% 12% 5% 7% 6% 3 4 4 4 6% 25%	2660
	21st to end	Night	19% 15% 5% 7% 5% 3 5% 5% 5% 6% 25%	2783
December	1st to 10th	Night	20% 16% 6% 8% 6% 3 5% 4 4 5% 24%	2850
	11th to 20th	Night	22% 17% 7% 11% 7% 3 4 4 3 4 19%	3531
	21st to end	Night	21% 13% 5% 7% 6% 3 5% 5% 4 6% 24%	5225

Transparency (when cloud cover <= 30%)
Color Meanings: Too cloudy to forecast Poor Below Average Average Above average Transparent
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	65% 7% 9% 12% 6% 1	1327
	11th to 20th	Day	65% 5% 9% 14% 7% 1	1505
	21st to end	Day	66% 5% 8% 10% 10% 1	1593
February	1st to 10th	Day	62% 6% 11% 11% 9% 1	1509
	11th to 20th	Day	64% 8% 9% 12% 7% 1	1612
	21st to end	Day	59% 7% 10% 13% 9% 2	1480
March	1st to 10th	Day	63% 5% 9% 12% 8% 2	1800
	11th to 20th	Day	66% 6% 8% 13% 6%	1966
	21st to end	Day	73% 4 7% 9% 5% 2	2200
April	1st to 10th	Day	66% 7% 8% 13% 6% 1	2173
	11th to 20th	Day	64% 6% 8% 12% 9% 1	2311
	21st to end	Day	68% 6% 9% 9% 7% 1	2340
May	1st to 10th	Day	69% 6% 8% 10% 6%	2340
	11th to 20th	Day	64% 8% 11% 11% 6%	2550
	21st to end	Day	61% 9% 12% 14% 5%	2918
June	1st to 10th	Day	71% 7% 7% 11% 4	2700
	11th to 20th	Day	64% 7% 12% 12% 4 1	2700
	21st to end	Day	61% 9% 11% 14% 5%	2700
July	1st to 10th	Day	54% 10% 14% 17% 5%	2625
	11th to 20th	Day	57% 9% 14% 13% 6%	2594
	21st to end	Day	61% 11% 13% 12% 4	2592
August	1st to 10th	Day	58% 10% 12% 16% 4	2417
	11th to 20th	Day	59% 9% 13% 13% 6%	2305
	21st to end	Day	55% 9% 14% 18% 4	2574
September	1st to 10th	Day	52% 8% 13% 19% 8% 1	2154
	11th to 20th	Day	54% 7% 11% 18% 8% 1	1980
	21st to end	Day	50% 7% 17% 19% 7% 1	1980
October	1st to 10th	Day	53% 7% 12% 18% 9% 1	1909
	11th to 20th	Day	63% 5% 12% 14% 6%	1715
	21st to end	Day	64% 7% 9% 14% 6% 1	1782
November	1st to 10th	Day	59% 8% 15% 11% 6% 1	1658
	11th to 20th	Day	61% 8% 10% 14% 6% 1	1520
	21st to end	Day	64% 7% 10% 11% 6% 1	1397
December	1st to 10th	Day	67% 6% 9% 12% 6%	1330
	11th to 20th	Day	67% 7% 9% 11% 5%	1667
	21st to end	Day	67% 7% 10% 12% 4	2442
January	1st to 10th	Night	63% 7% 9% 13% 7% 1	2839
	11th to 20th	Night	62% 7% 9% 14% 8% 1	2672
	21st to end	Night	60% 6% 10% 14% 9% 1	2797
February	1st to 10th	Night	59% 5% 11% 14% 8% 1	2449
	11th to 20th	Night	63% 7% 10% 15% 5% 1	2245
	21st to end	Night	57% 5% 11% 14% 11% 1	1776
March	1st to 10th	Night	58% 6% 9% 15% 10% 2	2160
	11th to 20th	Night	59% 7% 12% 14% 8% 1	1994
	21st to end	Night	70% 4 6% 12% 7% 1	2154
April	1st to 10th	Night	62% 6% 9% 12% 10% 1	1787
	11th to 20th	Night	63% 4 9% 17% 7% 1	1598
	21st to end	Night	66% 5% 8% 12% 8% 1	1620
May	1st to 10th	Night	67% 7% 9% 12% 5%	1620
	11th to 20th	Night	60% 8% 10% 15% 7%	1346
	21st to end	Night	61% 9% 11% 11% 6% 1	1357
June	1st to 10th	Night	66% 8% 10% 10% 5%	1260
	11th to 20th	Night	63% 8% 12% 12% 5%	1260
	21st to end	Night	60% 10% 12% 12% 6%	1260
July	1st to 10th	Night	56% 11% 14% 14% 5%	1226
	11th to 20th	Night	56% 10% 14% 15% 5%	1239
	21st to end	Night	59% 8% 13% 16% 3	1486
August	1st to 10th	Night	53% 11% 19% 13% 5%	1495
	11th to 20th	Night	55% 10% 13% 17% 6%	1595
	21st to end	Night	48% 9% 18% 19% 6%	1782
September	1st to 10th	Night	49% 7% 16% 19% 8% 1	1801
	11th to 20th	Night	54% 7% 13% 15% 10% 1	1980
	21st to end	Night	51% 7% 13% 20% 8% 1	1980
October	1st to 10th	Night	53% 6% 14% 18% 8% 1	2050
	11th to 20th	Night	57% 7% 13% 16% 7%	2244
	21st to end	Night	62% 6% 11% 15% 6% 1	2574
November	1st to 10th	Night	59% 8% 14% 14% 5%	2417
	11th to 20th	Night	61% 8% 10% 15% 5% 1	2660
	21st to end	Night	57% 8% 12% 14% 7% 1	2783
December	1st to 10th	Night	63% 6% 9% 14% 7%	2850
	11th to 20th	Night	71% 5% 8% 10% 6%	3533
	21st to end	Night	61% 7% 12% 16% 4	5225

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
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	27% 19% 32% 18% 3 1	370
	11th to 20th	Day	24% 19% 34% 16% 5% 1	370
	21st to end	Day	22% 20% 36% 18% 5%	378
February	1st to 10th	Day	24% 23% 30% 18% 4	340
	11th to 20th	Day	24% 24% 34% 15% 3	336
	21st to end	Day	19% 21% 40% 15% 4 1	280
March	1st to 10th	Day	24% 26% 30% 15% 4 1	340
	11th to 20th	Day	24% 23% 29% 14% 8% 2	340
	21st to end	Day	27% 18% 33% 15% 4 3	384
April	1st to 10th	Day	29% 20% 30% 15% 5% 1	433
	11th to 20th	Day	29% 17% 31% 17% 6%	589
	21st to end	Day	30% 15% 29% 20% 6% 1	600
May	1st to 10th	Day	30% 17% 28% 17% 5% 3	603
	11th to 20th	Day	24% 14% 31% 19% 9% 3	624
	21st to end	Day	25% 15% 33% 21% 5% 1	680
June	1st to 10th	Day	38% 11% 25% 19% 7%	630
	11th to 20th	Day	33% 12% 24% 21% 8% 2	630
	21st to end	Day	25% 10% 31% 21% 10% 3	630
July	1st to 10th	Day	26% 11% 31% 22% 8% 2	620
	11th to 20th	Day	20% 7% 36% 26% 10% 1	618
	21st to end	Day	25% 11% 29% 26% 10%	685
August	1st to 10th	Day	25% 7% 28% 28% 9% 2	625
	11th to 20th	Day	24% 10% 25% 28% 11% 2	617
	21st to end	Day	20% 11% 30% 24% 13% 2	693
September	1st to 10th	Day	19% 10% 30% 27% 12% 2	469
	11th to 20th	Day	31% 12% 28% 22% 6% 1	360
	21st to end	Day	21% 13% 37% 22% 6% 2	360
October	1st to 10th	Day	19% 15% 36% 23% 6% 1	360
	11th to 20th	Day	32% 13% 27% 18% 6% 4	360
	21st to end	Day	22% 22% 32% 14% 8% 1	396
November	1st to 10th	Day	30% 18% 29% 16% 5% 1	365
	11th to 20th	Day	32% 16% 29% 17% 7%	370
	21st to end	Day	31% 22% 30% 12% 4	370
December	1st to 10th	Day	29% 17% 30% 17% 6% 1	370
	11th to 20th	Day	29% 25% 31% 12% 3	370
	21st to end	Day	25% 18% 36% 16% 5% 1	407
January	1st to 10th	Night	25% 19% 33% 19% 3	850
	11th to 20th	Night	25% 20% 34% 17% 4	850
	21st to end	Night	25% 16% 35% 21% 2	889
February	1st to 10th	Night	25% 20% 37% 16% 2	800
	11th to 20th	Night	29% 21% 34% 13% 3	769
	21st to end	Night	17% 18% 38% 22% 5% 1	592
March	1st to 10th	Night	25% 17% 36% 17% 5%	720
	11th to 20th	Night	19% 18% 30% 23% 9% 1	554
	21st to end	Night	30% 15% 30% 22% 3	594
April	1st to 10th	Night	28% 18% 31% 18% 5%	540
	11th to 20th	Night	28% 13% 34% 19% 5%	534
	21st to end	Night	33% 9% 33% 21% 4	540
May	1st to 10th	Night	30% 9% 31% 24% 5% 1	540
	11th to 20th	Night	31% 9% 28% 24% 8%	532
	21st to end	Night	30% 12% 31% 21% 5%	583
June	1st to 10th	Night	34% 11% 27% 22% 5% 1	540
	11th to 20th	Night	28% 7% 29% 28% 6%	540
	21st to end	Night	27% 9% 32% 22% 9% 1	540
July	1st to 10th	Night	22% 7% 36% 27% 7% 1	526
	11th to 20th	Night	22% 9% 36% 28% 5%	522
	21st to end	Night	25% 7% 33% 29% 6%	590
August	1st to 10th	Night	26% 6% 28% 31% 10% 1	538
	11th to 20th	Night	25% 7% 27% 33% 8%	532
	21st to end	Night	21% 8% 28% 32% 10%	594
September	1st to 10th	Night	20% 10% 32% 28% 10%	540
	11th to 20th	Night	26% 11% 30% 29% 4	540
	21st to end	Night	26% 10% 31% 26% 5%	540
October	1st to 10th	Night	23% 12% 34% 24% 6%	576
	11th to 20th	Night	29% 13% 29% 21% 7%	714
	21st to end	Night	29% 14% 30% 21% 5% 1	891
November	1st to 10th	Night	27% 18% 30% 20% 4	830
	11th to 20th	Night	29% 18% 28% 21% 5%	850
	21st to end	Night	25% 21% 34% 16% 4	850
December	1st to 10th	Night	27% 17% 31% 19% 6%	850
	11th to 20th	Night	32% 20% 30% 15% 3	850
	21st to end	Night	23% 15% 35% 20% 5% 1	935

Page generated at 2024-01-19 10:28:32. Version ac07

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