La Ronge
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the La Ronge clear sky chart from 2005-11-06 to 2026-01-02.

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	9% 9% 4 9% 6% 5% 5% 4 6% 7% 34%	131532
	Night	8% 11% 4 11% 7% 6% 6% 4 6% 7% 30%	128482
Transparency	Day	46% 4 15% 25% 9% 1	131216
	Night	53% 4 13% 22% 7%	128379
Seeing	Day	15% 5% 22% 32% 21% 6%	17337
	Night	16% 5% 24% 34% 18% 3	26588

By Month

Percentage Cloud Cover NW (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	5% 12% 8% 24% 11% 6% 5% 3 4 3 18%	2725
	11th to 20th	Day	6% 11% 5% 13% 10% 9% 9% 6% 11% 6% 15%	2930
	21st to end	Day	6% 17% 8% 18% 7% 5% 4 4 5% 6% 20%	3561
February	1st to 10th	Day	5% 10% 4 13% 8% 10% 10% 6% 6% 8% 20%	1600
	11th to 20th	Day	6% 10% 5% 9% 7% 8% 8% 5% 6% 6% 30%	1695
	21st to end	Day	4 10% 5% 13% 8% 7% 7% 3 8% 7% 28%	1518
March	1st to 10th	Day	4 11% 6% 14% 7% 7% 7% 4 6% 7% 28%	4500
	11th to 20th	Day	5% 10% 4 10% 8% 8% 5% 4 5% 6% 35%	4783
	21st to end	Day	5% 11% 5% 12% 5% 4 6% 4 5% 7% 36%	5876
April	1st to 10th	Day	7% 9% 3 8% 5% 6% 6% 5% 5% 7% 39%	2400
	11th to 20th	Day	10% 12% 4 10% 6% 5% 5% 4 6% 7% 31%	2574
	21st to end	Day	11% 8% 3 9% 6% 6% 5% 4 7% 6% 35%	2800
May	1st to 10th	Day	9% 9% 4 7% 5% 5% 5% 4 6% 8% 39%	6340
	11th to 20th	Day	17% 9% 4 7% 5% 4 4 4 6% 8% 32%	6778
	21st to end	Day	12% 9% 3 8% 5% 4 5% 4 5% 6% 39%	7907
June	1st to 10th	Day	16% 9% 3 8% 6% 6% 5% 4 6% 8% 31%	3200
	11th to 20th	Day	19% 8% 3 8% 5% 5% 5% 5% 7% 8% 27%	3200
	21st to end	Day	15% 8% 3 6% 5% 5% 5% 5% 8% 7% 32%	3200
July	1st to 10th	Day	6% 3 1 5% 4 5% 6% 5% 8% 11% 47%	7240
	11th to 20th	Day	6% 4 2 5% 4 5% 5% 4 7% 9% 49%	7240
	21st to end	Day	8% 4 2 7% 4 5% 6% 5% 7% 9% 42%	7495
August	1st to 10th	Day	7% 5% 2 6% 4 4 5% 4 8% 11% 45%	4583
	11th to 20th	Day	10% 7% 2 7% 5% 5% 6% 5% 7% 9% 38%	4483
	21st to end	Day	10% 6% 2 6% 5% 4 5% 4 6% 9% 42%	4735
September	1st to 10th	Day	12% 7% 2 8% 6% 5% 5% 5% 6% 7% 37%	2400
	11th to 20th	Day	16% 10% 4 9% 5% 4 5% 4 6% 7% 31%	2400
	21st to end	Day	13% 9% 3 8% 4 4 4 4 5% 8% 40%	2140
October	1st to 10th	Day	13% 11% 4 8% 5% 5% 5% 4 6% 7% 32%	3270
	11th to 20th	Day	11% 11% 4 8% 6% 5% 6% 5% 7% 8% 30%	3029
	21st to end	Day	15% 15% 6% 12% 6% 5% 5% 4 6% 6% 21%	3043
November	1st to 10th	Day	15% 20% 7% 13% 6% 5% 4 3 4 4 17%	1645
	11th to 20th	Day	13% 15% 6% 16% 9% 6% 5% 4 4 4 17%	1470
	21st to end	Day	8% 17% 7% 16% 9% 7% 4 3 6% 5% 18%	1375
December	1st to 10th	Day	8% 18% 7% 15% 9% 5% 8% 4 4 6% 15%	2020
	11th to 20th	Day	7% 10% 4 15% 10% 8% 8% 5% 7% 5% 22%	2319
	21st to end	Day	3 12% 5% 15% 9% 5% 4 3 5% 5% 34%	3058
January	1st to 10th	Night	5% 12% 8% 22% 9% 7% 6% 4 5% 5% 18%	7243
	11th to 20th	Night	4 10% 5% 15% 11% 10% 9% 8% 8% 6% 16%	6953
	21st to end	Night	6% 15% 7% 15% 8% 7% 6% 5% 5% 5% 22%	7397
February	1st to 10th	Night	7% 12% 4 11% 8% 7% 8% 6% 7% 7% 23%	2800
	11th to 20th	Night	5% 10% 5% 11% 7% 6% 9% 7% 5% 5% 31%	2611
	21st to end	Night	3 11% 4 11% 9% 7% 6% 5% 7% 7% 29%	2112
March	1st to 10th	Night	6% 11% 6% 13% 7% 7% 6% 4 6% 7% 27%	5374
	11th to 20th	Night	6% 12% 4 11% 8% 6% 5% 4 6% 8% 29%	5203
	21st to end	Night	5% 11% 5% 12% 5% 5% 4 3 5% 6% 40%	5081
April	1st to 10th	Night	8% 11% 3 9% 6% 6% 5% 4 6% 7% 35%	2000
	11th to 20th	Night	12% 9% 4 9% 7% 5% 5% 4 5% 7% 33%	1775
	21st to end	Night	11% 10% 4 7% 5% 5% 6% 4 5% 8% 36%	1600
May	1st to 10th	Night	12% 10% 3 8% 5% 5% 5% 4 6% 6% 35%	3640
	11th to 20th	Night	18% 7% 2 6% 4 5% 5% 5% 6% 8% 35%	3124
	21st to end	Night	12% 10% 3 7% 4 3 3 2 5% 9% 44%	2968
June	1st to 10th	Night	15% 7% 3 7% 6% 5% 5% 5% 8% 8% 33%	1200
	11th to 20th	Night	16% 6% 3 9% 6% 4 6% 5% 7% 9% 28%	1200
	21st to end	Night	15% 8% 3 8% 4 5% 4 3 7% 8% 34%	1200
July	1st to 10th	Night	6% 3 1 5% 4 4 6% 5% 9% 12% 44%	2720
	11th to 20th	Night	6% 4 1 6% 4 4 4 4 6% 9% 51%	2720
	21st to end	Night	10% 5% 2 5% 4 4 5% 4 7% 9% 45%	3345
August	1st to 10th	Night	9% 4 2 5% 4 3 5% 4 7% 10% 48%	2576
	11th to 20th	Night	9% 4 2 6% 5% 5% 5% 5% 7% 9% 44%	2576
	21st to end	Night	9% 4 2 5% 3 4 5% 5% 7% 8% 48%	3170
September	1st to 10th	Night	11% 6% 3 7% 5% 4 5% 4 6% 9% 40%	2000
	11th to 20th	Night	15% 8% 2 6% 4 4 5% 4 6% 8% 37%	2000
	21st to end	Night	11% 5% 2 5% 4 4 4 4 7% 9% 44%	2258
October	1st to 10th	Night	15% 10% 3 7% 4 3 3 3 5% 8% 38%	3920
	11th to 20th	Night	10% 13% 4 9% 5% 4 5% 4 5% 7% 33%	4086
	21st to end	Night	14% 17% 6% 11% 5% 5% 5% 4 5% 6% 23%	4753
November	1st to 10th	Night	15% 18% 6% 14% 8% 5% 4 3 4 6% 18%	2872
	11th to 20th	Night	12% 15% 6% 15% 10% 7% 5% 3 4 4 19%	3150
	21st to end	Night	7% 16% 6% 14% 10% 7% 5% 5% 5% 5% 20%	3242
December	1st to 10th	Night	8% 17% 7% 17% 11% 10% 7% 4 4 4 12%	5380
	11th to 20th	Night	8% 12% 4 15% 7% 7% 8% 7% 5% 6% 21%	6093
	21st to end	Night	4 13% 6% 14% 7% 5% 5% 4 5% 5% 32%	8140

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% 2 9% 14% 5%	2725
	11th to 20th	Day	61% 4 11% 18% 5%	2950
	21st to end	Day	65% 3 13% 14% 5%	3561
February	1st to 10th	Day	58% 4 10% 20% 8%	1600
	11th to 20th	Day	52% 3 12% 25% 9%	1704
	21st to end	Day	52% 3 14% 22% 8% 1	1518
March	1st to 10th	Day	52% 4 13% 26% 4 1	4500
	11th to 20th	Day	49% 3 12% 23% 13%	4784
	21st to end	Day	43% 4 7% 25% 20% 1	5876
April	1st to 10th	Day	43% 3 15% 24% 13% 1	2400
	11th to 20th	Day	49% 3 13% 22% 12% 1	2574
	21st to end	Day	46% 3 9% 28% 12% 2	2800
May	1st to 10th	Day	42% 2 9% 31% 13% 1	6340
	11th to 20th	Day	50% 2 12% 25% 10% 1	6782
	21st to end	Day	45% 2 10% 25% 16% 2	7908
June	1st to 10th	Day	49% 3 11% 24% 12% 1	3200
	11th to 20th	Day	52% 3 13% 22% 8% 1	3200
	21st to end	Day	46% 5% 15% 24% 9% 1	3200
July	1st to 10th	Day	27% 5% 22% 37% 8%	7161
	11th to 20th	Day	27% 6% 16% 41% 10%	7153
	21st to end	Day	33% 7% 22% 33% 5%	7285
August	1st to 10th	Day	30% 4 28% 34% 4	4566
	11th to 20th	Day	39% 7% 26% 24% 4	4525
	21st to end	Day	38% 5% 24% 30% 4	4734
September	1st to 10th	Day	43% 5% 20% 22% 9% 1	2400
	11th to 20th	Day	51% 4 19% 22% 4	2400
	21st to end	Day	43% 4 19% 26% 7% 1	2140
October	1st to 10th	Day	50% 4 16% 25% 5%	3270
	11th to 20th	Day	50% 6% 15% 23% 4	3029
	21st to end	Day	64% 7% 13% 14% 2	3043
November	1st to 10th	Day	71% 4 8% 13% 4	1645
	11th to 20th	Day	71% 4 11% 10% 3	1470
	21st to end	Day	68% 5% 12% 11% 4	1375
December	1st to 10th	Day	70% 5% 10% 12% 3	2020
	11th to 20th	Day	61% 4 15% 16% 4	2320
	21st to end	Day	53% 3 12% 22% 10%	3058
January	1st to 10th	Night	69% 3 9% 16% 4	7243
	11th to 20th	Night	64% 3 11% 17% 4	6995
	21st to end	Night	63% 5% 15% 13% 5%	7397
February	1st to 10th	Night	55% 5% 13% 17% 10%	2800
	11th to 20th	Night	53% 4 13% 23% 7%	2612
	21st to end	Night	52% 4 11% 23% 9%	2112
March	1st to 10th	Night	55% 3 12% 22% 7% 1	5374
	11th to 20th	Night	54% 2 9% 27% 8%	5203
	21st to end	Night	45% 3 5% 25% 21% 1	5081
April	1st to 10th	Night	48% 3 12% 23% 13% 2	2000
	11th to 20th	Night	50% 3 8% 21% 16% 2	1775
	21st to end	Night	47% 4 9% 26% 13% 2	1600
May	1st to 10th	Night	49% 2 6% 26% 16% 1	3640
	11th to 20th	Night	48% 3 10% 26% 11% 2	3124
	21st to end	Night	41% 1 9% 25% 22% 2	2968
June	1st to 10th	Night	46% 4 12% 21% 15% 2	1200
	11th to 20th	Night	50% 6% 11% 21% 11% 1	1200
	21st to end	Night	47% 4 14% 23% 11% 1	1200
July	1st to 10th	Night	27% 8% 20% 39% 6%	2690
	11th to 20th	Night	28% 5% 17% 40% 10%	2684
	21st to end	Night	34% 6% 18% 36% 6%	3250
August	1st to 10th	Night	29% 5% 23% 37% 6%	2569
	11th to 20th	Night	36% 6% 25% 27% 7%	2600
	21st to end	Night	32% 5% 20% 38% 5%	3170
September	1st to 10th	Night	41% 4 20% 25% 8% 1	2000
	11th to 20th	Night	45% 5% 19% 27% 5%	2000
	21st to end	Night	36% 4 17% 32% 9% 1	2258
October	1st to 10th	Night	45% 4 16% 29% 6%	3920
	11th to 20th	Night	50% 5% 14% 26% 5%	4086
	21st to end	Night	63% 7% 13% 15% 3	4753
November	1st to 10th	Night	70% 4 10% 12% 4	2872
	11th to 20th	Night	70% 4 12% 11% 3	3150
	21st to end	Night	67% 6% 11% 13% 3	3242
December	1st to 10th	Night	76% 5% 8% 9% 2	5380
	11th to 20th	Night	62% 4 12% 17% 4	6091
	21st to end	Night	56% 3 10% 23% 8%	8140

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	10% 5% 29% 32% 20% 5%	202
	11th to 20th	Day	14% 5% 29% 34% 14% 5%	200
	21st to end	Day	15% 6% 25% 35% 15% 3	233
February	1st to 10th	Day	7% 5% 29% 37% 18% 3	300
	11th to 20th	Day	6% 4 24% 39% 21% 6%	300
	21st to end	Day	8% 6% 26% 30% 27% 3	249
March	1st to 10th	Day	11% 4 22% 32% 23% 7%	300
	11th to 20th	Day	10% 5% 24% 35% 21% 5%	401
	21st to end	Day	14% 3 26% 31% 20% 6%	550
April	1st to 10th	Day	11% 4 23% 41% 15% 6%	500
	11th to 20th	Day	15% 4 25% 34% 17% 5%	586
	21st to end	Day	14% 4 23% 35% 20% 5%	700
May	1st to 10th	Day	13% 5% 21% 35% 19% 7%	703
	11th to 20th	Day	14% 5% 21% 32% 22% 5%	725
	21st to end	Day	16% 3 17% 34% 23% 7%	789
June	1st to 10th	Day	20% 7% 21% 28% 19% 4	730
	11th to 20th	Day	21% 5% 19% 31% 19% 4	730
	21st to end	Day	17% 2 17% 31% 24% 9%	730
July	1st to 10th	Day	13% 3 17% 32% 27% 7%	721
	11th to 20th	Day	12% 4 17% 29% 27% 11%	718
	21st to end	Day	12% 2 16% 31% 28% 9%	794
August	1st to 10th	Day	12% 4 15% 30% 30% 9%	726
	11th to 20th	Day	14% 2 20% 31% 23% 9%	715
	21st to end	Day	15% 5% 19% 31% 24% 7%	685
September	1st to 10th	Day	16% 8% 23% 32% 18% 3	530
	11th to 20th	Day	18% 5% 20% 35% 17% 5%	530
	21st to end	Day	14% 8% 27% 29% 19% 3	345
October	1st to 10th	Day	18% 8% 26% 31% 16% 1	330
	11th to 20th	Day	18% 10% 31% 26% 10% 3	330
	21st to end	Day	23% 9% 26% 26% 13% 4	363
November	1st to 10th	Day	21% 7% 28% 29% 15% 2	330
	11th to 20th	Day	18% 12% 34% 28% 8%	330
	21st to end	Day	15% 6% 33% 35% 10% 2	280
December	1st to 10th	Day	13% 7% 28% 28% 20% 5%	220
	11th to 20th	Day	14% 6% 34% 33% 12% 1	220
	21st to end	Day	12% 2 27% 34% 19% 7%	242
January	1st to 10th	Night	16% 5% 27% 33% 18% 2	1006
	11th to 20th	Night	13% 3 30% 38% 13% 2	1000
	21st to end	Night	18% 8% 28% 33% 12% 2	1100
February	1st to 10th	Night	13% 3 29% 35% 17% 4	1000
	11th to 20th	Night	9% 3 23% 40% 21% 4	862
	21st to end	Night	6% 3 23% 41% 24% 3	660
March	1st to 10th	Night	13% 4 22% 37% 20% 3	800
	11th to 20th	Night	14% 3 28% 38% 15% 2	800
	21st to end	Night	14% 2 21% 32% 26% 5%	705
April	1st to 10th	Night	15% 1 22% 39% 20% 3	600
	11th to 20th	Night	17% 3 24% 39% 15% 3	593
	21st to end	Night	15% 3 24% 39% 17% 2	600
May	1st to 10th	Night	17% 3 20% 40% 18% 2	600
	11th to 20th	Night	14% 3 24% 36% 19% 4	518
	21st to end	Night	18% 3 13% 42% 20% 4	433
June	1st to 10th	Night	18% 5% 20% 31% 24% 3	400
	11th to 20th	Night	21% 3 20% 31% 21% 5%	400
	21st to end	Night	18% 3 14% 32% 28% 6%	400
July	1st to 10th	Night	12% 2 16% 33% 33% 4	390
	11th to 20th	Night	13% 3 14% 35% 29% 6%	388
	21st to end	Night	15% 2 14% 34% 28% 8%	438
August	1st to 10th	Night	15% 2 13% 30% 31% 9%	577
	11th to 20th	Night	13% 3 21% 32% 24% 7%	594
	21st to end	Night	15% 5% 13% 40% 23% 4	660
September	1st to 10th	Night	16% 3 22% 34% 24% 2	600
	11th to 20th	Night	21% 3 19% 38% 18% 1	600
	21st to end	Night	13% 5% 30% 36% 14% 1	673
October	1st to 10th	Night	28% 7% 25% 28% 12% 1	800
	11th to 20th	Night	21% 9% 26% 29% 12% 2	911
	21st to end	Night	21% 11% 29% 26% 11% 2	1100
November	1st to 10th	Night	25% 8% 27% 27% 12% 2	1025
	11th to 20th	Night	18% 8% 30% 32% 10% 2	1050
	21st to end	Night	15% 5% 35% 32% 11% 2	1050
December	1st to 10th	Night	11% 4 26% 37% 17% 3	1050
	11th to 20th	Night	16% 6% 28% 32% 15% 3	1050
	21st to end	Night	13% 4 21% 39% 20% 3	1155

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