Labrador City
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Labrador City clear sky chart from 2005-11-06 to 2025-12-18.

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	16% 14% 5% 11% 7% 6% 6% 4 6% 6% 19%	127938
	Night	13% 14% 5% 12% 7% 7% 6% 5% 6% 7% 18%	123353
Transparency	Day	64% 6% 10% 14% 6%	131242
	Night	64% 6% 10% 13% 6% 1	128141
Seeing	Day	22% 12% 27% 23% 13% 4	17575
	Night	20% 10% 30% 27% 11% 2	25138

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	6% 14% 8% 21% 11% 6% 5% 4 7% 8% 10%	3157
	11th to 20th	Day	4 11% 7% 20% 11% 7% 11% 5% 5% 7% 11%	3134
	21st to end	Day	2 6% 4 13% 9% 7% 8% 9% 11% 14% 19%	3630
February	1st to 10th	Day	3 13% 5% 11% 7% 7% 6% 7% 12% 11% 19%	1620
	11th to 20th	Day	4 15% 7% 15% 9% 7% 7% 5% 7% 11% 14%	1753
	21st to end	Day	5% 15% 5% 11% 7% 8% 8% 5% 9% 10% 19%	1500
March	1st to 10th	Day	11% 14% 4 11% 7% 8% 9% 6% 8% 8% 14%	4558
	11th to 20th	Day	10% 23% 9% 14% 6% 5% 5% 4 6% 6% 13%	4980
	21st to end	Day	12% 19% 7% 11% 5% 5% 11% 6% 5% 5% 15%	5466
April	1st to 10th	Day	14% 18% 6% 16% 9% 8% 6% 4 4 4 12%	2519
	11th to 20th	Day	11% 16% 4 14% 7% 6% 4 3 4 5% 25%	2572
	21st to end	Day	17% 17% 5% 13% 7% 5% 4 4 5% 5% 18%	2600
May	1st to 10th	Day	15% 21% 7% 12% 5% 4 4 3 4 4 21%	6565
	11th to 20th	Day	22% 13% 5% 9% 5% 4 4 3 5% 6% 23%	6775
	21st to end	Day	25% 13% 5% 8% 4 4 4 3 4 5% 23%	7451
June	1st to 10th	Day	24% 13% 4 9% 5% 4 4 3 4 6% 24%	3000
	11th to 20th	Day	23% 11% 4 9% 5% 5% 5% 4 6% 6% 21%	3000
	21st to end	Day	25% 9% 3 9% 6% 6% 6% 4 5% 7% 20%	3000
July	1st to 10th	Day	17% 8% 3 7% 5% 5% 5% 4 6% 7% 33%	6820
	11th to 20th	Day	21% 9% 3 10% 7% 6% 5% 4 6% 6% 21%	6820
	21st to end	Day	16% 10% 4 10% 8% 8% 8% 5% 8% 7% 16%	7428
August	1st to 10th	Day	16% 10% 4 11% 7% 7% 6% 4 7% 6% 21%	4748
	11th to 20th	Day	20% 10% 4 9% 7% 7% 6% 5% 6% 6% 21%	4175
	21st to end	Day	19% 9% 2 7% 5% 4 5% 4 5% 7% 31%	4675
September	1st to 10th	Day	23% 12% 4 10% 6% 6% 5% 3 6% 6% 21%	2512
	11th to 20th	Day	23% 15% 4 11% 7% 5% 4 3 5% 6% 17%	2224
	21st to end	Day	20% 19% 5% 11% 5% 5% 4 3 4 6% 18%	2200
October	1st to 10th	Day	22% 18% 6% 11% 5% 5% 4 2 5% 5% 17%	2014
	11th to 20th	Day	25% 20% 6% 11% 5% 4 4 2 4 5% 14%	1912
	21st to end	Day	21% 22% 9% 13% 5% 5% 4 3 3 3 12%	1910
November	1st to 10th	Day	20% 19% 7% 19% 9% 5% 5% 3 3 4 7%	1645
	11th to 20th	Day	15% 23% 7% 17% 9% 6% 5% 3 4 3 8%	1612
	21st to end	Day	13% 20% 7% 16% 11% 7% 7% 4 4 4 8%	1470
December	1st to 10th	Day	5% 16% 7% 18% 9% 8% 9% 6% 8% 6% 8%	2350
	11th to 20th	Day	11% 16% 5% 15% 13% 9% 7% 4 6% 6% 7%	2667
	21st to end	Day	9% 13% 6% 12% 8% 10% 7% 4 8% 10% 13%	3476
January	1st to 10th	Night	5% 18% 9% 18% 9% 6% 5% 4 7% 9% 10%	6808
	11th to 20th	Night	6% 12% 6% 19% 10% 10% 8% 4 6% 8% 10%	6771
	21st to end	Night	2 6% 3 12% 10% 9% 9% 8% 15% 11% 16%	7340
February	1st to 10th	Night	3 11% 5% 11% 10% 8% 7% 7% 9% 10% 19%	2780
	11th to 20th	Night	5% 16% 7% 14% 8% 7% 6% 4 8% 10% 15%	2533
	21st to end	Night	6% 13% 5% 13% 7% 6% 6% 5% 9% 10% 19%	2129
March	1st to 10th	Night	9% 15% 5% 9% 5% 7% 6% 7% 8% 9% 20%	5281
	11th to 20th	Night	12% 25% 8% 12% 5% 5% 4 4 5% 5% 14%	4979
	21st to end	Night	9% 17% 6% 13% 7% 5% 7% 6% 5% 6% 19%	5466
April	1st to 10th	Night	12% 18% 7% 14% 7% 7% 5% 3 4 5% 18%	1880
	11th to 20th	Night	14% 15% 4 10% 6% 4 5% 3 4 5% 29%	1778
	21st to end	Night	17% 14% 5% 11% 7% 5% 5% 4 4 5% 24%	1800
May	1st to 10th	Night	19% 19% 6% 11% 5% 3 3 3 3 3 25%	3440
	11th to 20th	Night	23% 12% 4 8% 4 3 4 3 5% 5% 28%	3138
	21st to end	Night	22% 15% 5% 8% 5% 4 4 4 5% 6% 23%	3446
June	1st to 10th	Night	19% 11% 4 8% 5% 5% 5% 3 5% 6% 28%	1400
	11th to 20th	Night	22% 11% 5% 8% 5% 6% 5% 4 4 6% 25%	1400
	21st to end	Night	22% 10% 3 10% 6% 5% 5% 4 6% 6% 24%	1400
July	1st to 10th	Night	17% 8% 3 7% 5% 4 4 3 5% 7% 37%	3160
	11th to 20th	Night	19% 8% 4 10% 5% 6% 6% 3 6% 7% 26%	3160
	21st to end	Night	15% 9% 4 8% 6% 5% 5% 4 7% 8% 28%	3446
August	1st to 10th	Night	13% 8% 4 9% 6% 6% 7% 5% 6% 8% 28%	2382
	11th to 20th	Night	19% 10% 4 11% 7% 6% 6% 5% 7% 8% 18%	2863
	21st to end	Night	14% 8% 2 6% 4 5% 5% 4 7% 9% 35%	3223
September	1st to 10th	Night	20% 11% 3 9% 6% 6% 5% 4 5% 6% 26%	1887
	11th to 20th	Night	21% 13% 4 9% 5% 5% 5% 4 6% 6% 23%	2174
	21st to end	Night	21% 13% 4 9% 6% 6% 5% 4 5% 6% 22%	2200
October	1st to 10th	Night	20% 17% 4 8% 5% 5% 5% 3 5% 6% 22%	2386
	11th to 20th	Night	24% 20% 6% 10% 5% 5% 3 2 4 6% 15%	2485
	21st to end	Night	23% 18% 6% 13% 6% 5% 4 4 4 4 13%	2930
November	1st to 10th	Night	17% 20% 7% 18% 10% 5% 5% 3 3 3 9%	2873
	11th to 20th	Night	17% 20% 8% 16% 9% 7% 4 2 4 4 8%	3006
	21st to end	Night	15% 19% 7% 16% 9% 7% 6% 4 4 6% 7%	3150
December	1st to 10th	Night	5% 15% 7% 17% 11% 10% 7% 5% 6% 7% 9%	5060
	11th to 20th	Night	11% 18% 7% 15% 10% 8% 6% 4 5% 8% 9%	5697
	21st to end	Night	8% 14% 7% 14% 9% 10% 8% 7% 7% 6% 9%	7502

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	70% 5% 5% 13% 7%	3158
	11th to 20th	Day	71% 6% 9% 8% 5%	3160
	21st to end	Day	49% 6% 10% 19% 14% 2	3630
February	1st to 10th	Day	52% 7% 10% 22% 9% 1	1620
	11th to 20th	Day	63% 6% 9% 14% 8%	1761
	21st to end	Day	56% 6% 9% 16% 11% 2	1500
March	1st to 10th	Day	64% 4 7% 9% 15% 2	4562
	11th to 20th	Day	71% 4 6% 9% 9% 2	4980
	21st to end	Day	71% 4 5% 9% 10% 1	5466
April	1st to 10th	Day	74% 7% 8% 7% 4	2519
	11th to 20th	Day	61% 6% 8% 13% 11% 1	2572
	21st to end	Day	67% 7% 10% 9% 7%	2600
May	1st to 10th	Day	66% 5% 9% 11% 9%	6577
	11th to 20th	Day	58% 7% 10% 20% 5%	6779
	21st to end	Day	62% 6% 11% 15% 6%	7451
June	1st to 10th	Day	61% 6% 11% 15% 6% 1	3000
	11th to 20th	Day	60% 7% 11% 15% 6%	3000
	21st to end	Day	62% 8% 12% 13% 4	3000
July	1st to 10th	Day	48% 6% 11% 27% 7%	6745
	11th to 20th	Day	61% 6% 12% 16% 4	6739
	21st to end	Day	63% 8% 15% 14% 1	7216
August	1st to 10th	Day	60% 8% 13% 16% 3	4733
	11th to 20th	Day	60% 8% 14% 15% 4	4214
	21st to end	Day	51% 8% 19% 19% 4	4675
September	1st to 10th	Day	63% 8% 14% 12% 3	2512
	11th to 20th	Day	67% 7% 12% 11% 2	2224
	21st to end	Day	67% 7% 11% 13% 2	2200
October	1st to 10th	Day	63% 5% 12% 17% 2	3274
	11th to 20th	Day	77% 5% 7% 9% 2	3089
	21st to end	Day	75% 5% 8% 10% 2	3066
November	1st to 10th	Day	81% 6% 7% 4 2	1645
	11th to 20th	Day	81% 6% 8% 3 2	1612
	21st to end	Day	78% 8% 6% 6% 2	1470
December	1st to 10th	Day	71% 8% 8% 10% 3	2350
	11th to 20th	Day	74% 8% 10% 5% 2	2667
	21st to end	Day	65% 6% 11% 14% 4 1	3476
January	1st to 10th	Night	69% 6% 6% 12% 6% 1	6808
	11th to 20th	Night	70% 7% 8% 10% 4	6820
	21st to end	Night	51% 6% 12% 18% 10% 3	7340
February	1st to 10th	Night	55% 7% 9% 17% 10% 1	2780
	11th to 20th	Night	63% 6% 8% 15% 9%	2536
	21st to end	Night	56% 7% 10% 15% 10% 2	2129
March	1st to 10th	Night	56% 5% 7% 12% 17% 1	5290
	11th to 20th	Night	71% 4 5% 10% 9% 2	4980
	21st to end	Night	66% 4 6% 9% 14% 1	5466
April	1st to 10th	Night	69% 5% 8% 9% 8% 1	1880
	11th to 20th	Night	57% 6% 9% 15% 13% 2	1778
	21st to end	Night	63% 6% 9% 15% 7%	1800
May	1st to 10th	Night	64% 4 8% 14% 9% 1	3445
	11th to 20th	Night	56% 6% 10% 21% 7%	3139
	21st to end	Night	60% 7% 13% 17% 4	3447
June	1st to 10th	Night	55% 7% 12% 18% 8%	1400
	11th to 20th	Night	58% 8% 11% 19% 4	1400
	21st to end	Night	58% 9% 11% 18% 5%	1400
July	1st to 10th	Night	46% 7% 13% 28% 5%	3125
	11th to 20th	Night	56% 7% 14% 17% 6%	3118
	21st to end	Night	49% 9% 15% 23% 3	3343
August	1st to 10th	Night	52% 10% 17% 20% 2	2373
	11th to 20th	Night	61% 9% 15% 13% 2	2890
	21st to end	Night	44% 8% 20% 24% 5%	3223
September	1st to 10th	Night	58% 8% 14% 18% 2	1887
	11th to 20th	Night	60% 9% 14% 14% 3	2174
	21st to end	Night	61% 8% 14% 15% 2	2200
October	1st to 10th	Night	58% 6% 15% 18% 3	3906
	11th to 20th	Night	72% 6% 10% 9% 3	4047
	21st to end	Night	75% 6% 7% 8% 3 1	4728
November	1st to 10th	Night	80% 6% 7% 6% 1	2873
	11th to 20th	Night	80% 6% 6% 6% 2	3006
	21st to end	Night	77% 8% 8% 5% 2	3150
December	1st to 10th	Night	73% 6% 7% 8% 5%	5060
	11th to 20th	Night	74% 6% 10% 7% 3	5698
	21st to end	Night	70% 7% 8% 10% 4 2	7502

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	8% 10% 32% 28% 19% 6%	200
	11th to 20th	Day	8% 11% 30% 30% 16% 6%	200
	21st to end	Day	10% 9% 38% 30% 10% 4	220
February	1st to 10th	Day	8% 8% 37% 23% 17% 7%	220
	11th to 20th	Day	7% 12% 36% 29% 14% 3	396
	21st to end	Day	10% 10% 35% 27% 15% 3	339
March	1st to 10th	Day	13% 13% 29% 25% 16% 4	500
	11th to 20th	Day	13% 14% 28% 26% 14% 4	500
	21st to end	Day	15% 16% 34% 23% 9% 3	550
April	1st to 10th	Day	19% 15% 34% 21% 8% 3	500
	11th to 20th	Day	15% 15% 26% 26% 12% 5%	492
	21st to end	Day	23% 12% 26% 21% 12% 5%	500
May	1st to 10th	Day	30% 9% 24% 23% 10% 5%	703
	11th to 20th	Day	20% 12% 26% 19% 17% 7%	724
	21st to end	Day	27% 12% 23% 22% 13% 3	790
June	1st to 10th	Day	26% 8% 21% 27% 15% 3	730
	11th to 20th	Day	29% 9% 22% 22% 14% 3	730
	21st to end	Day	27% 9% 25% 20% 14% 4	730
July	1st to 10th	Day	23% 9% 26% 22% 15% 6%	720
	11th to 20th	Day	28% 9% 22% 25% 13% 3	718
	21st to end	Day	24% 7% 21% 26% 15% 5%	795
August	1st to 10th	Day	28% 8% 20% 23% 16% 5%	656
	11th to 20th	Day	22% 9% 19% 23% 22% 6%	519
	21st to end	Day	26% 9% 20% 22% 17% 6%	583
September	1st to 10th	Day	30% 13% 28% 19% 7% 2	530
	11th to 20th	Day	25% 15% 30% 20% 8% 2	530
	21st to end	Day	26% 18% 29% 16% 8% 3	530
October	1st to 10th	Day	25% 19% 30% 16% 7% 3	427
	11th to 20th	Day	33% 12% 24% 20% 8% 3	420
	21st to end	Day	30% 14% 24% 20% 11% 3	462
November	1st to 10th	Day	26% 17% 32% 19% 5% 1	425
	11th to 20th	Day	23% 14% 31% 23% 8% 2	362
	21st to end	Day	15% 16% 37% 20% 10% 3	220
December	1st to 10th	Day	13% 10% 26% 27% 20% 5%	220
	11th to 20th	Day	16% 14% 36% 21% 10% 3	214
	21st to end	Day	14% 13% 33% 23% 15% 2	220
January	1st to 10th	Night	13% 8% 32% 30% 15% 3	900
	11th to 20th	Night	12% 10% 35% 30% 11% 3	900
	21st to end	Night	10% 8% 36% 33% 12% 2	954
February	1st to 10th	Night	7% 9% 32% 33% 15% 4	800
	11th to 20th	Night	11% 11% 36% 27% 13% 2	783
	21st to end	Night	11% 8% 33% 30% 14% 3	660
March	1st to 10th	Night	11% 9% 33% 30% 15% 3	800
	11th to 20th	Night	14% 10% 35% 26% 14% 1	800
	21st to end	Night	16% 13% 34% 28% 9% 2	880
April	1st to 10th	Night	20% 9% 35% 29% 6% 1	655
	11th to 20th	Night	20% 7% 31% 28% 10% 4	594
	21st to end	Night	24% 10% 27% 28% 9% 2	600
May	1st to 10th	Night	27% 8% 25% 28% 10% 1	529
	11th to 20th	Night	24% 8% 26% 25% 14% 3	394
	21st to end	Night	27% 11% 25% 27% 10% 1	433
June	1st to 10th	Night	22% 7% 25% 36% 10%	400
	11th to 20th	Night	25% 10% 24% 29% 13%	400
	21st to end	Night	25% 7% 24% 29% 15% 1	400
July	1st to 10th	Night	24% 6% 23% 32% 14% 1	390
	11th to 20th	Night	23% 7% 25% 34% 11%	388
	21st to end	Night	20% 6% 20% 34% 18% 2	438
August	1st to 10th	Night	25% 5% 16% 35% 18% 1	398
	11th to 20th	Night	22% 7% 22% 30% 17% 2	583
	21st to end	Night	25% 7% 25% 28% 12% 2	660
September	1st to 10th	Night	25% 11% 29% 28% 6% 1	600
	11th to 20th	Night	27% 11% 28% 26% 7% 1	774
	21st to end	Night	25% 15% 31% 21% 8%	800
October	1st to 10th	Night	31% 15% 28% 21% 5%	800
	11th to 20th	Night	33% 9% 23% 25% 8% 2	800
	21st to end	Night	32% 12% 27% 19% 8% 2	919
November	1st to 10th	Night	27% 16% 30% 19% 6% 1	930
	11th to 20th	Night	25% 15% 30% 20% 9% 1	950
	21st to end	Night	23% 10% 32% 25% 9% 1	950
December	1st to 10th	Night	16% 9% 36% 27% 10% 3	950
	11th to 20th	Night	16% 11% 35% 27% 10% 1	936
	21st to end	Night	16% 12% 27% 29% 14% 2	990

Page generated at 2025-12-15 02:13:50. Version ac07

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