Salmon Arm
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Salmon Arm clear sky chart from 2005-11-06 to 2025-10-19.

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% 3 9% 6% 6% 6% 5% 7% 7% 33%	130590
	Night	10% 12% 4 10% 6% 6% 5% 4 6% 7% 30%	127759
Transparency	Day	47% 7% 16% 21% 9% 2	130302
	Night	53% 7% 15% 17% 7% 1	127624
Seeing	Day	15% 11% 24% 28% 17% 4	16930
	Night	20% 7% 19% 33% 18% 2	25224

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	11% 19% 8% 18% 8% 7% 5% 3 5% 6% 10%	3069
	11th to 20th	Day	8% 14% 5% 8% 8% 9% 6% 4 7% 10% 21%	3597
	21st to end	Day	8% 17% 7% 16% 7% 6% 5% 4 6% 6% 18%	4004
February	1st to 10th	Day	13% 18% 6% 13% 7% 5% 4 4 5% 5% 19%	1603
	11th to 20th	Day	10% 14% 4 11% 7% 5% 6% 5% 6% 6% 25%	1755
	21st to end	Day	10% 13% 5% 14% 7% 7% 6% 6% 6% 6% 19%	1626
March	1st to 10th	Day	5% 11% 5% 12% 7% 6% 7% 6% 8% 9% 22%	4518
	11th to 20th	Day	5% 9% 3 10% 7% 6% 6% 5% 8% 9% 32%	4727
	21st to end	Day	11% 14% 4 10% 7% 7% 7% 5% 6% 8% 22%	5940
April	1st to 10th	Day	10% 14% 5% 12% 8% 7% 6% 4 6% 7% 21%	2400
	11th to 20th	Day	10% 11% 4 10% 7% 6% 6% 5% 7% 7% 26%	2421
	21st to end	Day	10% 10% 5% 11% 7% 6% 6% 5% 6% 8% 26%	2750
May	1st to 10th	Day	9% 7% 3 8% 5% 5% 5% 5% 5% 7% 40%	6320
	11th to 20th	Day	8% 10% 3 11% 7% 7% 7% 6% 8% 9% 23%	6277
	21st to end	Day	14% 9% 3 9% 5% 5% 6% 4 6% 9% 31%	7196
June	1st to 10th	Day	15% 9% 3 8% 6% 6% 7% 5% 7% 6% 28%	3094
	11th to 20th	Day	15% 9% 4 8% 8% 7% 6% 5% 6% 7% 23%	3200
	21st to end	Day	11% 8% 3 9% 7% 5% 5% 4 6% 7% 36%	3200
July	1st to 10th	Day	5% 3 2 5% 4 4 4 4 5% 7% 57%	7158
	11th to 20th	Day	5% 3 1 4 3 4 4 4 6% 7% 60%	6518
	21st to end	Day	4 3 1 4 3 3 5% 4 7% 9% 56%	6874
August	1st to 10th	Day	3 2 1 4 3 4 5% 5% 7% 8% 57%	4541
	11th to 20th	Day	4 3 2 5% 4 5% 7% 5% 8% 9% 49%	4470
	21st to end	Day	7% 5% 2 6% 4 5% 6% 5% 7% 9% 45%	4405
September	1st to 10th	Day	8% 5% 2 6% 4 5% 4 4 6% 7% 49%	2400
	11th to 20th	Day	11% 6% 2 8% 6% 5% 4 4 6% 7% 40%	2370
	21st to end	Day	12% 8% 4 10% 6% 5% 5% 5% 7% 7% 32%	2190
October	1st to 10th	Day	8% 7% 3 9% 6% 5% 7% 5% 6% 7% 37%	3280
	11th to 20th	Day	17% 11% 3 8% 5% 5% 5% 3 6% 6% 31%	3094
	21st to end	Day	14% 13% 3 9% 7% 5% 6% 5% 8% 7% 22%	3101
November	1st to 10th	Day	18% 17% 4 11% 6% 6% 6% 4 4 7% 17%	1655
	11th to 20th	Day	17% 17% 4 11% 6% 6% 5% 4 6% 6% 17%	1587
	21st to end	Day	15% 20% 5% 13% 10% 7% 5% 4 5% 4 12%	1400
December	1st to 10th	Day	9% 11% 4 12% 9% 8% 7% 4 9% 6% 20%	2290
	11th to 20th	Day	12% 16% 7% 16% 8% 7% 7% 5% 6% 6% 10%	2568
	21st to end	Day	10% 15% 6% 15% 10% 8% 7% 5% 6% 6% 11%	2992
January	1st to 10th	Night	11% 21% 8% 18% 9% 7% 6% 4 4 4 8%	6906
	11th to 20th	Night	8% 12% 6% 13% 8% 6% 5% 4 7% 9% 22%	6284
	21st to end	Night	12% 16% 6% 15% 7% 5% 4 3 6% 5% 19%	6952
February	1st to 10th	Night	14% 21% 5% 11% 7% 5% 5% 4 5% 4 19%	2795
	11th to 20th	Night	11% 16% 6% 11% 6% 5% 4 3 6% 6% 27%	2532
	21st to end	Night	9% 16% 5% 12% 7% 7% 5% 4 5% 7% 22%	2003
March	1st to 10th	Night	7% 11% 4 8% 6% 6% 6% 5% 8% 10% 29%	5376
	11th to 20th	Night	6% 10% 4 10% 6% 6% 5% 5% 8% 8% 33%	5268
	21st to end	Night	8% 12% 4 10% 7% 7% 7% 5% 8% 8% 25%	5034
April	1st to 10th	Night	11% 12% 4 10% 5% 6% 6% 5% 7% 7% 28%	2000
	11th to 20th	Night	10% 13% 3 10% 7% 7% 6% 6% 7% 5% 27%	1930
	21st to end	Night	10% 12% 3 8% 6% 5% 5% 5% 6% 8% 32%	1650
May	1st to 10th	Night	7% 8% 3 8% 5% 6% 6% 5% 6% 7% 39%	3640
	11th to 20th	Night	10% 8% 4 10% 7% 5% 6% 4 6% 9% 32%	3616
	21st to end	Night	10% 9% 3 9% 6% 5% 5% 5% 5% 8% 35%	3665
June	1st to 10th	Night	16% 7% 3 8% 6% 5% 6% 4 6% 7% 32%	1302
	11th to 20th	Night	14% 9% 3 7% 7% 7% 7% 5% 8% 8% 26%	1200
	21st to end	Night	9% 6% 3 7% 6% 7% 6% 5% 7% 9% 36%	1200
July	1st to 10th	Night	8% 4 2 5% 4 3 4 4 5% 6% 55%	2799
	11th to 20th	Night	6% 4 1 4 3 3 4 3 6% 7% 60%	3428
	21st to end	Night	7% 2 1 4 3 4 5% 4 6% 9% 55%	3969
August	1st to 10th	Night	3 2 1 4 3 4 5% 5% 8% 11% 54%	2609
	11th to 20th	Night	5% 5% 2 6% 4 5% 5% 4 7% 11% 47%	2577
	21st to end	Night	9% 5% 2 6% 5% 5% 5% 4 6% 7% 46%	3495
September	1st to 10th	Night	8% 4 2 5% 4 5% 4 4 5% 7% 53%	2000
	11th to 20th	Night	11% 7% 2 7% 3 3 4 3 5% 7% 47%	2030
	21st to end	Night	14% 8% 2 6% 4 5% 4 3 5% 7% 41%	2206
October	1st to 10th	Night	10% 6% 2 7% 5% 5% 6% 6% 7% 8% 39%	3920
	11th to 20th	Night	13% 9% 3 8% 4 4 5% 3 6% 8% 37%	4014
	21st to end	Night	13% 9% 3 9% 5% 5% 6% 4 6% 8% 32%	4457
November	1st to 10th	Night	21% 13% 5% 11% 6% 5% 5% 5% 5% 5% 18%	2640
	11th to 20th	Night	17% 17% 5% 10% 6% 5% 5% 4 6% 6% 20%	2800
	21st to end	Night	16% 20% 6% 11% 8% 6% 6% 4 5% 5% 15%	2990
December	1st to 10th	Night	9% 11% 3 10% 8% 6% 5% 4 9% 9% 26%	4890
	11th to 20th	Night	12% 21% 8% 16% 8% 7% 5% 4 4 5% 11%	5618
	21st to end	Night	10% 17% 6% 15% 9% 7% 7% 5% 6% 6% 12%	7964

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	77% 8% 9% 6%	3069
	11th to 20th	Day	55% 10% 16% 13% 3 2	3621
	21st to end	Day	70% 7% 12% 10% 1	4004
February	1st to 10th	Day	67% 7% 9% 10% 6%	1603
	11th to 20th	Day	57% 10% 15% 12% 5% 1	1764
	21st to end	Day	61% 8% 14% 13% 3	1626
March	1st to 10th	Day	54% 9% 14% 18% 4	4518
	11th to 20th	Day	44% 6% 19% 27% 4	4727
	21st to end	Day	57% 7% 13% 17% 5%	5940
April	1st to 10th	Day	58% 10% 13% 16% 4	2400
	11th to 20th	Day	52% 7% 14% 19% 6% 2	2421
	21st to end	Day	53% 7% 15% 18% 7%	2750
May	1st to 10th	Day	40% 6% 11% 26% 16% 2	6320
	11th to 20th	Day	50% 7% 16% 21% 5%	6280
	21st to end	Day	47% 6% 16% 25% 5% 1	7197
June	1st to 10th	Day	50% 7% 12% 17% 11% 3	3094
	11th to 20th	Day	55% 7% 13% 18% 6% 1	3200
	21st to end	Day	43% 6% 16% 21% 11% 2	3200
July	1st to 10th	Day	25% 4 12% 27% 24% 9%	7080
	11th to 20th	Day	22% 4 17% 24% 23% 9%	6438
	21st to end	Day	21% 4 23% 32% 15% 4	6681
August	1st to 10th	Day	21% 5% 13% 37% 22% 2	4524
	11th to 20th	Day	28% 5% 25% 31% 10% 1	4512
	21st to end	Day	34% 6% 21% 30% 8% 1	4404
September	1st to 10th	Day	33% 6% 18% 30% 11% 2	2400
	11th to 20th	Day	42% 6% 17% 24% 11% 1	2370
	21st to end	Day	49% 9% 20% 15% 7% 1	2190
October	1st to 10th	Day	45% 6% 23% 21% 4 1	3280
	11th to 20th	Day	54% 5% 17% 22% 3	3094
	21st to end	Day	55% 8% 24% 10% 2	3101
November	1st to 10th	Day	70% 8% 12% 8% 3	1655
	11th to 20th	Day	64% 12% 12% 9% 2 1	1587
	21st to end	Day	76% 7% 11% 6% 1	1400
December	1st to 10th	Day	63% 11% 18% 7% 1	2290
	11th to 20th	Day	75% 7% 10% 6% 1	2570
	21st to end	Day	69% 9% 12% 9% 1	2992
January	1st to 10th	Night	79% 6% 9% 4 1	6906
	11th to 20th	Night	59% 11% 15% 10% 3 2	6322
	21st to end	Night	66% 7% 15% 11% 1	6952
February	1st to 10th	Night	70% 6% 9% 8% 6% 1	2795
	11th to 20th	Night	60% 7% 13% 14% 5% 1	2534
	21st to end	Night	60% 7% 15% 12% 5%	2003
March	1st to 10th	Night	48% 8% 18% 20% 6%	5376
	11th to 20th	Night	46% 7% 20% 22% 5%	5269
	21st to end	Night	54% 10% 13% 17% 7%	5034
April	1st to 10th	Night	52% 10% 16% 17% 6%	2000
	11th to 20th	Night	53% 8% 12% 18% 7% 1	1930
	21st to end	Night	48% 7% 14% 22% 8% 1	1650
May	1st to 10th	Night	41% 6% 9% 27% 15% 1	3637
	11th to 20th	Night	48% 6% 16% 24% 6%	3616
	21st to end	Night	43% 9% 15% 26% 6% 1	3665
June	1st to 10th	Night	48% 7% 10% 21% 11% 3	1302
	11th to 20th	Night	52% 9% 12% 20% 8%	1200
	21st to end	Night	40% 9% 17% 20% 12% 2	1200
July	1st to 10th	Night	30% 4 10% 23% 22% 12%	2768
	11th to 20th	Night	26% 4 14% 27% 22% 8%	3385
	21st to end	Night	25% 4 18% 31% 15% 6%	3857
August	1st to 10th	Night	20% 6% 13% 37% 21% 3	2601
	11th to 20th	Night	31% 5% 21% 29% 12% 2	2601
	21st to end	Night	36% 6% 23% 24% 10% 1	3495
September	1st to 10th	Night	30% 6% 16% 31% 15% 2	2000
	11th to 20th	Night	37% 6% 13% 26% 15% 2	2030
	21st to end	Night	44% 7% 16% 21% 10% 1	2206
October	1st to 10th	Night	42% 7% 24% 21% 6%	3920
	11th to 20th	Night	46% 6% 19% 23% 5%	4014
	21st to end	Night	53% 7% 21% 18% 2	4457
November	1st to 10th	Night	69% 9% 11% 8% 3	2640
	11th to 20th	Night	65% 10% 11% 9% 4	2800
	21st to end	Night	72% 7% 13% 6% 3	2990
December	1st to 10th	Night	55% 13% 22% 9% 1	4890
	11th to 20th	Night	78% 6% 11% 4 1	5615
	21st to end	Night	71% 9% 11% 7% 1	7964

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	21% 12% 25% 25% 12% 6%	200
	11th to 20th	Day	25% 9% 25% 23% 13% 6%	200
	21st to end	Day	23% 8% 32% 24% 11% 1	220
February	1st to 10th	Day	23% 19% 28% 23% 6% 1	203
	11th to 20th	Day	16% 12% 27% 30% 13% 2	395
	21st to end	Day	15% 11% 33% 26% 13% 2	402
March	1st to 10th	Day	18% 18% 27% 23% 13% 2	500
	11th to 20th	Day	19% 15% 24% 23% 16% 2	500
	21st to end	Day	21% 17% 25% 21% 14% 2	550
April	1st to 10th	Day	21% 19% 25% 22% 12% 2	500
	11th to 20th	Day	17% 19% 25% 24% 11% 4	492
	21st to end	Day	14% 17% 26% 27% 13% 4	500
May	1st to 10th	Day	15% 15% 27% 28% 13% 2	503
	11th to 20th	Day	13% 11% 22% 29% 21% 4	528
	21st to end	Day	17% 10% 21% 30% 18% 4	697
June	1st to 10th	Day	19% 12% 24% 29% 14% 1	824
	11th to 20th	Day	17% 11% 23% 31% 15% 3	930
	21st to end	Day	12% 8% 24% 29% 23% 3	930
July	1st to 10th	Day	12% 6% 21% 33% 24% 4	887
	11th to 20th	Day	6% 8% 25% 32% 23% 7%	613
	21st to end	Day	5% 6% 19% 35% 24% 9%	575
August	1st to 10th	Day	6% 5% 21% 31% 24% 13%	527
	11th to 20th	Day	9% 5% 21% 31% 23% 11%	517
	21st to end	Day	10% 8% 21% 32% 19% 11%	583
September	1st to 10th	Day	12% 8% 20% 30% 20% 10%	530
	11th to 20th	Day	12% 8% 25% 26% 24% 6%	530
	21st to end	Day	16% 12% 27% 26% 15% 3	530
October	1st to 10th	Day	17% 9% 24% 28% 17% 5%	530
	11th to 20th	Day	19% 12% 25% 23% 19% 3	439
	21st to end	Day	26% 10% 24% 25% 14% 1	330
November	1st to 10th	Day	24% 9% 29% 22% 14% 1	245
	11th to 20th	Day	25% 15% 27% 18% 14% 3	200
	21st to end	Day	25% 12% 23% 28% 10% 5%	200
December	1st to 10th	Day	20% 7% 25% 25% 18% 6%	200
	11th to 20th	Day	19% 14% 36% 19% 10% 5%	200
	21st to end	Day	25% 8% 19% 37% 8% 3	220
January	1st to 10th	Night	33% 12% 21% 24% 9% 2	962
	11th to 20th	Night	26% 8% 23% 30% 13% 1	800
	21st to end	Night	23% 7% 24% 31% 13% 2	880
February	1st to 10th	Night	27% 10% 21% 28% 14% 1	800
	11th to 20th	Night	21% 9% 19% 34% 16% 1	784
	21st to end	Night	19% 9% 20% 31% 18% 3	660
March	1st to 10th	Night	22% 9% 22% 28% 17% 2	800
	11th to 20th	Night	19% 9% 25% 29% 17% 1	800
	21st to end	Night	17% 7% 27% 31% 16% 2	880
April	1st to 10th	Night	18% 11% 19% 31% 19% 2	800
	11th to 20th	Night	17% 8% 25% 35% 14% 1	742
	21st to end	Night	16% 8% 24% 37% 15%	450
May	1st to 10th	Night	12% 9% 21% 38% 20%	400
	11th to 20th	Night	12% 5% 19% 42% 21% 1	394
	21st to end	Night	17% 5% 18% 33% 25% 1	433
June	1st to 10th	Night	16% 9% 17% 43% 15% 1	400
	11th to 20th	Night	16% 7% 17% 39% 21% 1	400
	21st to end	Night	12% 5% 16% 40% 25% 3	400
July	1st to 10th	Night	11% 3 14% 37% 34% 1	390
	11th to 20th	Night	6% 4 18% 38% 31% 2	388
	21st to end	Night	8% 2 9% 42% 37% 2	438
August	1st to 10th	Night	6% 2 11% 33% 44% 4	398
	11th to 20th	Night	7% 1 10% 41% 37% 4	396
	21st to end	Night	8% 4 11% 42% 32% 2	806
September	1st to 10th	Night	11% 3 13% 38% 31% 6%	800
	11th to 20th	Night	14% 5% 12% 29% 35% 6%	800
	21st to end	Night	19% 4 18% 37% 19% 3	800
October	1st to 10th	Night	16% 4 19% 35% 24% 2	800
	11th to 20th	Night	20% 7% 19% 33% 20% 2	792
	21st to end	Night	24% 7% 22% 31% 13% 3	836
November	1st to 10th	Night	32% 7% 21% 32% 8%	780
	11th to 20th	Night	28% 10% 23% 25% 11% 2	800
	21st to end	Night	28% 9% 21% 28% 12% 3	990
December	1st to 10th	Night	24% 8% 19% 33% 13% 3	1000
	11th to 20th	Night	29% 7% 22% 31% 10% 1	1015
	21st to end	Night	32% 8% 22% 30% 8% 1	1210

Page generated at 2025-10-15 22:50:27. Version ac07

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