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 2025-01-07.

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	20% 13% 4 10% 6% 5% 5% 4 5% 6% 23%	104913
	Night	19% 13% 5% 9% 5% 4 4 3 5% 6% 26%	104280
Transparency	Day	61% 7% 11% 15% 6% 1	108398
	Night	59% 7% 12% 15% 7% 1	108909
Seeing	Day	26% 16% 31% 19% 7% 1	18332
	Night	26% 14% 32% 22% 5%	25077

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	15% 13% 8% 13% 5% 4 4 3 5% 6% 25%	2258
	11th to 20th	Day	17% 15% 5% 13% 5% 5% 4 3 4 4 25%	2503
	21st to end	Day	12% 14% 6% 12% 7% 4 5% 4 5% 5% 26%	2783
February	1st to 10th	Day	17% 14% 5% 12% 6% 5% 5% 5% 4 6% 22%	1593
	11th to 20th	Day	18% 14% 3 12% 8% 6% 5% 4 5% 5% 19%	1696
	21st to end	Day	12% 13% 4 11% 8% 7% 5% 4 6% 7% 23%	1570
March	1st to 10th	Day	21% 15% 5% 11% 5% 5% 4 3 4 4 23%	3114
	11th to 20th	Day	21% 19% 8% 10% 7% 5% 4 3 4 4 14%	3466
	21st to end	Day	20% 19% 6% 11% 6% 5% 5% 4 4 5% 15%	3865
April	1st to 10th	Day	18% 17% 6% 10% 6% 5% 5% 3 5% 6% 18%	2294
	11th to 20th	Day	21% 16% 5% 11% 5% 4 4 4 4 6% 22%	2441
	21st to end	Day	22% 20% 5% 9% 6% 4 4 3 4 5% 18%	2470
May	1st to 10th	Day	24% 23% 6% 11% 5% 4 3 3 3 4 13%	4105
	11th to 20th	Day	25% 16% 4 10% 5% 5% 4 3 4 6% 19%	4517
	21st to end	Day	23% 16% 5% 9% 5% 4 4 3 5% 6% 20%	5173
June	1st to 10th	Day	30% 15% 4 8% 5% 5% 4 3 4 4 16%	2850
	11th to 20th	Day	25% 13% 3 8% 6% 4 4 4 5% 6% 22%	2850
	21st to end	Day	22% 11% 4 9% 6% 5% 5% 4 5% 7% 23%	2850
July	1st to 10th	Day	23% 11% 4 8% 6% 5% 5% 4 5% 6% 23%	4750
	11th to 20th	Day	13% 9% 4 10% 6% 7% 6% 6% 7% 9% 24%	4700
	21st to end	Day	15% 7% 3 7% 6% 5% 5% 4 6% 7% 35%	4815
August	1st to 10th	Day	19% 9% 4 10% 7% 7% 6% 4 6% 7% 21%	4280
	11th to 20th	Day	16% 8% 3 8% 5% 5% 6% 4 6% 8% 31%	4046
	21st to end	Day	17% 9% 3 8% 5% 5% 5% 3 6% 8% 31%	4532
September	1st to 10th	Day	18% 9% 3 9% 5% 4 4 4 6% 6% 32%	2273
	11th to 20th	Day	25% 9% 3 6% 5% 4 4 3 4 7% 30%	2090
	21st to end	Day	17% 10% 4 9% 5% 5% 4 3 5% 8% 31%	2090
October	1st to 10th	Day	19% 11% 3 7% 4 5% 4 4 4 6% 32%	2015
	11th to 20th	Day	22% 14% 3 9% 5% 5% 4 3 5% 5% 25%	1810
	21st to end	Day	23% 13% 4 10% 6% 5% 6% 3 5% 5% 21%	1881
November	1st to 10th	Day	21% 12% 4 8% 5% 5% 5% 4 5% 6% 26%	1747
	11th to 20th	Day	23% 15% 4 9% 5% 4 4 3 3 6% 23%	1600
	21st to end	Day	24% 15% 4 9% 5% 5% 4 4 5% 4 22%	1470
December	1st to 10th	Day	14% 13% 3 8% 4 4 6% 5% 7% 8% 27%	2290
	11th to 20th	Day	14% 15% 5% 10% 5% 4 4 3 4 6% 29%	2628
	21st to end	Day	20% 17% 6% 12% 6% 4 4 3 4 5% 19%	3498
January	1st to 10th	Night	15% 14% 7% 11% 5% 5% 4 3 5% 5% 25%	4830
	11th to 20th	Night	13% 12% 6% 11% 5% 4 5% 4 6% 7% 27%	4464
	21st to end	Night	12% 12% 5% 12% 7% 5% 5% 4 5% 5% 29%	4884
February	1st to 10th	Night	17% 12% 4 11% 6% 5% 4 4 5% 6% 26%	2585
	11th to 20th	Night	19% 14% 5% 10% 6% 5% 5% 4 5% 6% 22%	2369
	21st to end	Night	10% 15% 5% 10% 6% 5% 4 4 5% 6% 30%	1884
March	1st to 10th	Night	23% 11% 4 11% 4 4 4 3 4 5% 26%	3726
	11th to 20th	Night	16% 15% 7% 13% 7% 5% 5% 4 6% 6% 15%	3493
	21st to end	Night	24% 17% 5% 11% 5% 4 4 3 4 5% 19%	3765
April	1st to 10th	Night	23% 17% 5% 7% 5% 3 3 3 4 5% 24%	1886
	11th to 20th	Night	23% 16% 5% 7% 5% 3 4 3 4 5% 25%	1688
	21st to end	Night	23% 19% 6% 7% 4 4 3 2 4 6% 23%	1710
May	1st to 10th	Night	27% 20% 8% 8% 4 4 3 3 4 5% 14%	2845
	11th to 20th	Night	26% 17% 6% 13% 5% 3 3 3 3 4 16%	2357
	21st to end	Night	23% 13% 5% 9% 5% 5% 4 4 5% 6% 22%	2412
June	1st to 10th	Night	28% 13% 5% 8% 5% 5% 5% 3 4 4 19%	1330
	11th to 20th	Night	25% 11% 4 8% 6% 5% 4 4 4 6% 23%	1330
	21st to end	Night	22% 12% 3 8% 5% 4 5% 5% 5% 8% 23%	1330
July	1st to 10th	Night	25% 10% 4 9% 5% 5% 4 4 5% 7% 22%	2220
	11th to 20th	Night	12% 8% 4 10% 8% 7% 7% 5% 6% 9% 25%	2267
	21st to end	Night	13% 7% 3 8% 6% 5% 5% 4 6% 7% 37%	2750
August	1st to 10th	Night	14% 7% 3 7% 5% 5% 6% 5% 9% 10% 29%	2658
	11th to 20th	Night	21% 8% 3 6% 3 3 3 3 5% 7% 38%	2791
	21st to end	Night	22% 7% 3 7% 4 4 4 3 5% 7% 35%	3135
September	1st to 10th	Night	19% 9% 2 7% 3 5% 4 3 6% 8% 33%	1902
	11th to 20th	Night	22% 9% 2 7% 4 5% 5% 3 4 6% 31%	2090
	21st to end	Night	20% 12% 3 7% 4 4 4 3 5% 7% 32%	2090
October	1st to 10th	Night	21% 11% 3 7% 4 4 4 3 5% 7% 31%	2164
	11th to 20th	Night	21% 13% 3 7% 5% 4 4 4 6% 7% 27%	2369
	21st to end	Night	23% 14% 3 8% 5% 4 5% 3 4 6% 26%	2717
November	1st to 10th	Night	19% 13% 4 8% 5% 5% 5% 4 5% 5% 26%	2548
	11th to 20th	Night	25% 13% 4 8% 6% 4 4 3 4 6% 24%	2800
	21st to end	Night	20% 17% 4 8% 4 4 5% 4 5% 6% 24%	2930
December	1st to 10th	Night	16% 13% 4 8% 5% 4 4 3 5% 6% 31%	4900
	11th to 20th	Night	17% 15% 5% 11% 6% 5% 4 3 4 5% 26%	5581
	21st to end	Night	19% 15% 6% 10% 5% 5% 4 3 4 5% 23%	7480

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	60% 8% 6% 15% 8% 2	2259
	11th to 20th	Day	63% 7% 7% 14% 9% 1	2503
	21st to end	Day	60% 6% 8% 13% 12% 1	2783
February	1st to 10th	Day	63% 6% 11% 10% 9% 1	1593
	11th to 20th	Day	65% 8% 9% 11% 6% 1	1703
	21st to end	Day	59% 7% 10% 12% 9% 2	1570
March	1st to 10th	Day	64% 6% 10% 11% 8% 2	3118
	11th to 20th	Day	74% 7% 7% 8% 4	3466
	21st to end	Day	72% 6% 7% 11% 3 1	3865
April	1st to 10th	Day	67% 7% 8% 12% 5% 1	2294
	11th to 20th	Day	64% 6% 8% 13% 8% 1	2441
	21st to end	Day	68% 6% 8% 9% 7% 1	2470
May	1st to 10th	Day	74% 7% 8% 7% 4	4120
	11th to 20th	Day	67% 7% 11% 11% 3	4521
	21st to end	Day	64% 8% 10% 14% 4	5173
June	1st to 10th	Day	71% 7% 7% 11% 4	2850
	11th to 20th	Day	62% 7% 12% 13% 5% 1	2850
	21st to end	Day	62% 8% 11% 14% 5%	2850
July	1st to 10th	Day	60% 8% 13% 15% 5%	4675
	11th to 20th	Day	53% 11% 19% 12% 5%	4618
	21st to end	Day	46% 8% 17% 24% 6%	4662
August	1st to 10th	Day	59% 10% 13% 15% 3	4266
	11th to 20th	Day	49% 9% 15% 22% 5%	4085
	21st to end	Day	50% 7% 15% 24% 4	4532
September	1st to 10th	Day	51% 7% 12% 20% 8% 1	2273
	11th to 20th	Day	54% 7% 12% 19% 8% 1	2090
	21st to end	Day	51% 7% 16% 18% 7%	2090
October	1st to 10th	Day	61% 7% 9% 17% 5%	3357
	11th to 20th	Day	53% 5% 15% 18% 9%	2997
	21st to end	Day	61% 6% 9% 18% 6% 1	3092
November	1st to 10th	Day	59% 8% 15% 12% 6% 1	1747
	11th to 20th	Day	63% 7% 10% 14% 6% 1	1600
	21st to end	Day	66% 7% 10% 10% 6% 1	1470
December	1st to 10th	Day	55% 6% 12% 20% 7%	2290
	11th to 20th	Day	58% 5% 16% 12% 8%	2627
	21st to end	Day	67% 6% 9% 13% 5%	3498
January	1st to 10th	Night	61% 6% 8% 13% 9% 3	4830
	11th to 20th	Night	55% 8% 11% 16% 9% 1	4464
	21st to end	Night	56% 8% 12% 12% 9% 3	4884
February	1st to 10th	Night	61% 5% 11% 14% 8% 2	2585
	11th to 20th	Night	63% 7% 10% 15% 5% 1	2373
	21st to end	Night	56% 5% 11% 14% 11% 2	1884
March	1st to 10th	Night	60% 6% 9% 16% 9% 1	3735
	11th to 20th	Night	66% 9% 11% 10% 4 1	3494
	21st to end	Night	68% 6% 8% 13% 4 1	3765
April	1st to 10th	Night	64% 6% 8% 12% 9% 1	1886
	11th to 20th	Night	63% 4 8% 16% 7% 1	1688
	21st to end	Night	65% 5% 8% 12% 8% 1	1710
May	1st to 10th	Night	72% 7% 10% 7% 3	2850
	11th to 20th	Night	71% 7% 7% 10% 4	2358
	21st to end	Night	63% 9% 11% 12% 4 1	2413
June	1st to 10th	Night	67% 9% 10% 10% 5%	1330
	11th to 20th	Night	62% 8% 13% 12% 5%	1330
	21st to end	Night	60% 10% 12% 12% 5%	1330
July	1st to 10th	Night	63% 8% 11% 16% 3	2186
	11th to 20th	Night	52% 16% 15% 11% 5%	2225
	21st to end	Night	46% 9% 18% 24% 3	2663
August	1st to 10th	Night	46% 14% 19% 17% 3	2647
	11th to 20th	Night	47% 7% 15% 26% 5%	2818
	21st to end	Night	49% 7% 15% 24% 4	3134
September	1st to 10th	Night	49% 7% 15% 19% 9% 1	1902
	11th to 20th	Night	54% 7% 14% 15% 10% 1	2090
	21st to end	Night	52% 7% 13% 20% 8% 1	2090
October	1st to 10th	Night	58% 6% 15% 15% 5%	3606
	11th to 20th	Night	48% 6% 17% 19% 9%	3931
	21st to end	Night	53% 5% 12% 20% 9%	4467
November	1st to 10th	Night	59% 7% 14% 14% 5%	2548
	11th to 20th	Night	62% 8% 10% 15% 5% 1	2800
	21st to end	Night	59% 8% 12% 13% 7% 1	2930
December	1st to 10th	Night	55% 5% 9% 21% 10%	4900
	11th to 20th	Night	61% 6% 15% 13% 6%	5583
	21st to end	Night	63% 6% 9% 15% 6%	7480

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	29% 19% 31% 17% 3 1	388
	11th to 20th	Day	24% 19% 34% 17% 5% 1	370
	21st to end	Day	21% 21% 35% 18% 4	407
February	1st to 10th	Day	25% 22% 29% 19% 4 1	370
	11th to 20th	Day	24% 24% 34% 14% 3	366
	21st to end	Day	18% 22% 41% 14% 4 1	307
March	1st to 10th	Day	26% 26% 30% 14% 5% 1	370
	11th to 20th	Day	24% 23% 28% 15% 8% 2	370
	21st to end	Day	27% 19% 32% 15% 4 2	419
April	1st to 10th	Day	29% 20% 31% 15% 4 1	474
	11th to 20th	Day	29% 17% 31% 16% 6%	639
	21st to end	Day	31% 16% 30% 18% 5% 1	650
May	1st to 10th	Day	30% 17% 28% 17% 5% 3	653
	11th to 20th	Day	25% 14% 31% 19% 9% 3	674
	21st to end	Day	25% 15% 33% 21% 5% 1	735
June	1st to 10th	Day	38% 12% 25% 18% 7%	680
	11th to 20th	Day	31% 13% 25% 22% 8% 1	680
	21st to end	Day	26% 11% 31% 21% 9% 3	680
July	1st to 10th	Day	26% 11% 30% 22% 8% 2	670
	11th to 20th	Day	19% 8% 36% 26% 10% 1	668
	21st to end	Day	23% 11% 31% 25% 10%	740
August	1st to 10th	Day	24% 9% 29% 27% 9% 2	675
	11th to 20th	Day	22% 10% 26% 28% 12% 2	667
	21st to end	Day	20% 12% 30% 24% 13% 2	748
September	1st to 10th	Day	19% 11% 30% 27% 11% 2	508
	11th to 20th	Day	30% 13% 28% 22% 6% 1	390
	21st to end	Day	23% 13% 35% 21% 6% 2	390
October	1st to 10th	Day	19% 15% 35% 23% 6% 1	390
	11th to 20th	Day	31% 14% 28% 18% 6% 4	390
	21st to end	Day	23% 23% 31% 14% 8% 1	429
November	1st to 10th	Day	30% 19% 30% 16% 5% 1	395
	11th to 20th	Day	35% 16% 27% 17% 6%	400
	21st to end	Day	34% 21% 28% 12% 5%	400
December	1st to 10th	Day	28% 18% 31% 18% 6% 1	400
	11th to 20th	Day	28% 25% 32% 12% 3	400
	21st to end	Day	25% 17% 34% 16% 7% 1	440
January	1st to 10th	Night	26% 18% 33% 19% 3	881
	11th to 20th	Night	25% 20% 34% 17% 4	850
	21st to end	Night	24% 16% 36% 21% 3	935
February	1st to 10th	Night	25% 19% 36% 17% 3	850
	11th to 20th	Night	29% 21% 34% 13% 4	817
	21st to end	Night	17% 18% 37% 22% 5% 1	628
March	1st to 10th	Night	26% 17% 36% 17% 5%	760
	11th to 20th	Night	19% 18% 29% 24% 9% 1	584
	21st to end	Night	30% 15% 29% 23% 3	627
April	1st to 10th	Night	29% 18% 31% 17% 5%	570
	11th to 20th	Night	28% 14% 34% 18% 5%	564
	21st to end	Night	32% 10% 33% 21% 4	570
May	1st to 10th	Night	30% 11% 30% 24% 5% 1	570
	11th to 20th	Night	31% 9% 27% 24% 8%	562
	21st to end	Night	29% 12% 32% 21% 5%	616
June	1st to 10th	Night	34% 12% 27% 22% 5% 1	570
	11th to 20th	Night	28% 9% 30% 27% 6%	570
	21st to end	Night	26% 11% 32% 22% 8% 1	570
July	1st to 10th	Night	22% 8% 35% 27% 7% 1	556
	11th to 20th	Night	21% 10% 35% 28% 5%	552
	21st to end	Night	23% 7% 35% 29% 6%	623
August	1st to 10th	Night	25% 6% 29% 31% 9% 1	568
	11th to 20th	Night	25% 7% 28% 32% 8%	562
	21st to end	Night	22% 9% 27% 32% 10%	627
September	1st to 10th	Night	21% 10% 31% 28% 10%	570
	11th to 20th	Night	26% 11% 29% 29% 4	570
	21st to end	Night	27% 12% 31% 25% 5% 1	570
October	1st to 10th	Night	24% 12% 33% 24% 7%	610
	11th to 20th	Night	28% 14% 30% 21% 7%	759
	21st to end	Night	29% 14% 30% 21% 5% 1	946
November	1st to 10th	Night	27% 18% 31% 20% 4	880
	11th to 20th	Night	31% 17% 27% 20% 5%	900
	21st to end	Night	27% 21% 32% 16% 4	900
December	1st to 10th	Night	27% 17% 31% 20% 6%	900
	11th to 20th	Night	31% 21% 29% 16% 3	900
	21st to end	Night	24% 15% 34% 21% 6% 1	990

Page generated at 2025-01-04 04:24:00. Version ac07

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