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 2024-11-05.

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	10% 10% 4 9% 6% 5% 6% 4 6% 7% 33%	105542
	Night	12% 12% 4 10% 6% 5% 5% 4 6% 7% 29%	102035
Transparency	Day	48% 7% 15% 19% 9% 2	105296
	Night	54% 7% 14% 16% 7% 1	101927
Seeing	Day	16% 11% 24% 28% 17% 4	15663
	Night	21% 7% 20% 32% 18% 2	24017

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	15% 20% 7% 17% 7% 6% 4 3 5% 5% 11%	2137
	11th to 20th	Day	12% 19% 6% 9% 8% 6% 6% 4 5% 8% 17%	2497
	21st to end	Day	10% 20% 9% 18% 7% 5% 5% 5% 6% 5% 10%	2794
February	1st to 10th	Day	13% 19% 7% 14% 7% 5% 4 4 6% 5% 18%	1522
	11th to 20th	Day	11% 14% 4 11% 7% 5% 6% 5% 6% 7% 25%	1665
	21st to end	Day	10% 13% 5% 15% 7% 8% 6% 6% 6% 5% 19%	1547
March	1st to 10th	Day	6% 14% 6% 15% 8% 7% 6% 5% 7% 7% 20%	3138
	11th to 20th	Day	7% 8% 2 8% 5% 6% 6% 5% 7% 8% 37%	3295
	21st to end	Day	9% 13% 4 10% 7% 7% 7% 5% 6% 8% 25%	4149
April	1st to 10th	Day	10% 15% 5% 12% 8% 7% 6% 4 6% 7% 20%	2280
	11th to 20th	Day	11% 12% 4 10% 8% 6% 6% 5% 7% 7% 26%	2298
	21st to end	Day	11% 10% 5% 12% 7% 6% 6% 5% 6% 8% 24%	2612
May	1st to 10th	Day	8% 8% 4 10% 6% 6% 6% 5% 6% 8% 35%	4420
	11th to 20th	Day	8% 9% 3 9% 6% 6% 6% 6% 8% 10% 28%	4377
	21st to end	Day	16% 12% 4 11% 6% 6% 6% 4 6% 7% 22%	5022
June	1st to 10th	Day	15% 9% 3 9% 6% 6% 7% 5% 7% 6% 26%	2939
	11th to 20th	Day	16% 10% 4 9% 9% 7% 6% 5% 6% 7% 22%	3040
	21st to end	Day	11% 8% 3 8% 7% 5% 5% 4 7% 7% 36%	3040
July	1st to 10th	Day	5% 4 2 5% 4 4 4 3 5% 6% 58%	5006
	11th to 20th	Day	3 3 1 3 3 3 3 3 5% 6% 66%	4562
	21st to end	Day	4 3 2 5% 4 4 5% 4 7% 8% 55%	4790
August	1st to 10th	Day	3 2 1 4 3 4 5% 5% 6% 8% 58%	4401
	11th to 20th	Day	4 3 2 5% 4 4 7% 5% 8% 9% 49%	4330
	21st to end	Day	7% 5% 2 6% 4 5% 6% 5% 7% 9% 44%	4270
September	1st to 10th	Day	8% 5% 2 6% 4 5% 4 4 6% 7% 47%	2280
	11th to 20th	Day	11% 7% 2 8% 6% 6% 5% 4 6% 7% 38%	2252
	21st to end	Day	12% 9% 4 10% 6% 5% 5% 5% 7% 7% 31%	2081
October	1st to 10th	Day	9% 7% 3 9% 6% 5% 7% 5% 6% 7% 37%	3180
	11th to 20th	Day	17% 11% 3 8% 5% 5% 5% 3 6% 6% 31%	3016
	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% 5% 4 6% 17%	1607
	11th to 20th	Day	17% 16% 4 11% 6% 6% 5% 4 6% 6% 18%	1508
	21st to end	Day	16% 20% 4 12% 10% 6% 5% 4 5% 4 13%	1330
December	1st to 10th	Day	15% 17% 5% 13% 8% 8% 7% 4 4 4 15%	1330
	11th to 20th	Day	17% 20% 7% 17% 8% 6% 6% 4 4 4 8%	1636
	21st to end	Day	14% 16% 6% 14% 10% 8% 7% 4 5% 4 11%	2090
January	1st to 10th	Night	15% 25% 8% 15% 8% 6% 5% 3 4 4 8%	4824
	11th to 20th	Night	12% 16% 7% 15% 8% 6% 5% 3 5% 8% 15%	4384
	21st to end	Night	17% 21% 8% 18% 8% 6% 5% 3 4 3 9%	4862
February	1st to 10th	Night	15% 22% 5% 11% 7% 5% 5% 4 5% 4 18%	2656
	11th to 20th	Night	12% 16% 6% 11% 6% 5% 4 3 6% 6% 26%	2402
	21st to end	Night	9% 17% 5% 12% 7% 7% 5% 4 5% 7% 21%	1906
March	1st to 10th	Night	10% 13% 4 10% 6% 6% 5% 5% 7% 8% 25%	3736
	11th to 20th	Night	7% 9% 3 7% 5% 5% 5% 4 6% 7% 41%	3680
	21st to end	Night	9% 12% 4 9% 6% 6% 6% 4 7% 7% 29%	3503
April	1st to 10th	Night	11% 12% 4 9% 5% 6% 6% 5% 7% 6% 28%	1900
	11th to 20th	Night	10% 13% 3 10% 7% 7% 6% 6% 7% 5% 26%	1833
	21st to end	Night	10% 12% 3 8% 6% 5% 5% 5% 7% 8% 31%	1568
May	1st to 10th	Night	8% 10% 4 10% 7% 6% 6% 4 5% 7% 34%	2540
	11th to 20th	Night	10% 8% 3 9% 6% 5% 6% 5% 7% 9% 32%	2516
	21st to end	Night	13% 12% 4 11% 6% 6% 5% 5% 5% 7% 25%	2553
June	1st to 10th	Night	17% 8% 3 9% 6% 5% 6% 5% 6% 6% 31%	1237
	11th to 20th	Night	14% 9% 3 7% 8% 7% 6% 5% 8% 9% 25%	1140
	21st to end	Night	8% 6% 3 6% 6% 7% 6% 5% 7% 9% 36%	1140
July	1st to 10th	Night	7% 4 2 4 4 3 4 4 6% 5% 57%	1951
	11th to 20th	Night	4 3 1 4 3 3 3 3 5% 7% 65%	2398
	21st to end	Night	8% 2 1 4 3 4 4 4 6% 7% 57%	2762
August	1st to 10th	Night	2 2 1 4 3 4 5% 5% 7% 11% 55%	2529
	11th to 20th	Night	4 5% 2 6% 4 5% 5% 4 7% 11% 47%	2497
	21st to end	Night	9% 5% 2 6% 6% 5% 5% 4 6% 7% 45%	3388
September	1st to 10th	Night	8% 4 2 5% 4 5% 4 4 5% 6% 52%	1900
	11th to 20th	Night	11% 7% 2 7% 4 3 4 3 5% 7% 46%	1928
	21st to end	Night	14% 8% 3 7% 4 5% 4 3 5% 7% 40%	2095
October	1st to 10th	Night	10% 6% 2 7% 5% 5% 6% 6% 7% 8% 39%	3800
	11th to 20th	Night	14% 9% 3 8% 4 4 5% 3 6% 8% 36%	3916
	21st to end	Night	13% 9% 3 9% 5% 5% 6% 4 6% 8% 32%	4457
November	1st to 10th	Night	22% 14% 5% 11% 6% 6% 5% 5% 5% 5% 18%	2568
	11th to 20th	Night	17% 17% 5% 10% 6% 5% 5% 4 5% 5% 21%	2660
	21st to end	Night	17% 20% 6% 11% 7% 5% 6% 4 5% 5% 15%	2840
December	1st to 10th	Night	15% 17% 5% 12% 6% 6% 5% 4 5% 7% 17%	2850
	11th to 20th	Night	17% 21% 8% 18% 7% 6% 4 3 4 4 9%	3550
	21st to end	Night	13% 17% 6% 16% 10% 7% 6% 4 5% 5% 11%	5566

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	78% 9% 7% 6% 1	2137
	11th to 20th	Day	65% 8% 13% 8% 3 3	2521
	21st to end	Day	78% 8% 8% 5% 1	2794
February	1st to 10th	Day	69% 8% 10% 9% 4	1522
	11th to 20th	Day	58% 10% 15% 12% 5%	1674
	21st to end	Day	62% 8% 14% 12% 3 1	1547
March	1st to 10th	Day	60% 9% 11% 16% 4 1	3138
	11th to 20th	Day	41% 7% 23% 26% 3	3295
	21st to end	Day	55% 7% 16% 16% 5%	4149
April	1st to 10th	Day	59% 10% 12% 15% 4	2280
	11th to 20th	Day	53% 7% 14% 18% 7% 1	2298
	21st to end	Day	55% 7% 14% 17% 7%	2612
May	1st to 10th	Day	44% 7% 14% 23% 12%	4420
	11th to 20th	Day	45% 9% 15% 23% 7%	4380
	21st to end	Day	58% 8% 14% 15% 5% 1	5023
June	1st to 10th	Day	52% 7% 13% 16% 9% 3	2939
	11th to 20th	Day	56% 7% 13% 17% 6% 1	3040
	21st to end	Day	43% 6% 16% 22% 11% 2	3040
July	1st to 10th	Day	26% 4 10% 23% 25% 12%	4928
	11th to 20th	Day	18% 5% 9% 25% 31% 12%	4482
	21st to end	Day	23% 4 16% 31% 18% 6%	4639
August	1st to 10th	Day	20% 5% 13% 37% 23% 2	4384
	11th to 20th	Day	28% 5% 25% 31% 10% 1	4372
	21st to end	Day	35% 6% 22% 30% 7%	4269
September	1st to 10th	Day	34% 6% 17% 29% 10% 2	2280
	11th to 20th	Day	43% 6% 17% 23% 10% 1	2252
	21st to end	Day	49% 9% 19% 15% 7% 1	2081
October	1st to 10th	Day	45% 6% 23% 21% 4 1	3180
	11th to 20th	Day	54% 5% 17% 22% 2	3016
	21st to end	Day	55% 8% 24% 10% 2	3101
November	1st to 10th	Day	70% 8% 11% 8% 3	1607
	11th to 20th	Day	64% 12% 12% 9% 2 1	1508
	21st to end	Day	75% 7% 11% 6% 1	1330
December	1st to 10th	Day	72% 8% 11% 8% 1	1330
	11th to 20th	Day	80% 8% 6% 4 1	1638
	21st to end	Day	70% 9% 11% 9% 1	2090
January	1st to 10th	Night	81% 6% 7% 5% 1	4824
	11th to 20th	Night	68% 8% 11% 7% 3 3	4422
	21st to end	Night	81% 6% 8% 4 1	4862
February	1st to 10th	Night	72% 6% 10% 7% 4 1	2656
	11th to 20th	Night	61% 7% 13% 13% 5% 1	2404
	21st to end	Night	60% 7% 15% 12% 6%	1906
March	1st to 10th	Night	54% 9% 12% 18% 7%	3736
	11th to 20th	Night	40% 7% 24% 24% 4	3681
	21st to end	Night	52% 7% 13% 19% 9%	3503
April	1st to 10th	Night	52% 10% 15% 17% 6%	1900
	11th to 20th	Night	54% 8% 12% 18% 7% 1	1833
	21st to end	Night	49% 7% 14% 21% 8% 1	1568
May	1st to 10th	Night	46% 7% 11% 23% 12% 1	2540
	11th to 20th	Night	46% 7% 14% 25% 8%	2516
	21st to end	Night	52% 11% 14% 17% 6%	2553
June	1st to 10th	Night	50% 7% 10% 20% 9% 3	1237
	11th to 20th	Night	53% 9% 12% 20% 7%	1140
	21st to end	Night	40% 9% 16% 20% 12% 2	1140
July	1st to 10th	Night	28% 5% 7% 21% 24% 15%	1920
	11th to 20th	Night	20% 4 7% 28% 29% 12%	2355
	21st to end	Night	25% 4 10% 32% 20% 8%	2674
August	1st to 10th	Night	19% 6% 13% 38% 22% 3	2521
	11th to 20th	Night	30% 5% 21% 29% 12% 2	2521
	21st to end	Night	36% 6% 24% 24% 9% 1	3388
September	1st to 10th	Night	31% 6% 15% 30% 15% 2	1900
	11th to 20th	Night	37% 6% 13% 25% 15% 2	1928
	21st to end	Night	45% 7% 16% 21% 10% 1	2095
October	1st to 10th	Night	42% 7% 23% 22% 6%	3800
	11th to 20th	Night	47% 6% 20% 23% 4	3916
	21st to end	Night	53% 7% 21% 18% 2	4457
November	1st to 10th	Night	70% 9% 10% 8% 3	2568
	11th to 20th	Night	66% 10% 11% 9% 4	2660
	21st to end	Night	72% 7% 13% 6% 3	2840
December	1st to 10th	Night	68% 8% 13% 9% 3	2850
	11th to 20th	Night	82% 6% 7% 4 1	3547
	21st to end	Night	72% 9% 11% 6% 2	5566

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	22% 12% 22% 26% 12% 6%	180
	11th to 20th	Day	27% 9% 24% 19% 13% 7%	180
	21st to end	Day	25% 8% 31% 23% 11% 2	198
February	1st to 10th	Day	25% 19% 29% 21% 5% 1	182
	11th to 20th	Day	16% 13% 27% 30% 12% 2	365
	21st to end	Day	15% 9% 34% 27% 13% 3	371
March	1st to 10th	Day	18% 19% 26% 22% 12% 2	460
	11th to 20th	Day	19% 15% 24% 23% 17% 2	460
	21st to end	Day	21% 16% 24% 22% 15% 2	506
April	1st to 10th	Day	22% 19% 26% 20% 12% 1	460
	11th to 20th	Day	18% 19% 25% 24% 12% 4	452
	21st to end	Day	15% 17% 27% 26% 13% 3	460
May	1st to 10th	Day	15% 15% 26% 30% 13% 2	463
	11th to 20th	Day	13% 11% 21% 30% 20% 5%	488
	21st to end	Day	17% 10% 21% 31% 18% 4	647
June	1st to 10th	Day	20% 12% 24% 28% 14% 1	769
	11th to 20th	Day	18% 12% 24% 30% 14% 2	870
	21st to end	Day	12% 9% 24% 29% 23% 3	870
July	1st to 10th	Day	12% 6% 21% 33% 24% 4	829
	11th to 20th	Day	6% 9% 23% 32% 23% 7%	569
	21st to end	Day	5% 6% 20% 36% 24% 8%	531
August	1st to 10th	Day	5% 5% 21% 32% 24% 12%	487
	11th to 20th	Day	8% 5% 20% 32% 24% 11%	477
	21st to end	Day	10% 9% 22% 33% 18% 9%	539
September	1st to 10th	Day	13% 8% 22% 32% 18% 8%	490
	11th to 20th	Day	13% 8% 26% 26% 23% 4	490
	21st to end	Day	16% 12% 25% 27% 16% 3	490
October	1st to 10th	Day	18% 9% 23% 29% 17% 5%	490
	11th to 20th	Day	20% 12% 25% 22% 19% 3	409
	21st to end	Day	26% 10% 24% 25% 14% 1	330
November	1st to 10th	Day	24% 11% 29% 21% 15% 1	233
	11th to 20th	Day	27% 13% 26% 18% 14% 3	180
	21st to end	Day	26% 11% 20% 27% 11% 5%	180
December	1st to 10th	Day	22% 7% 26% 25% 15% 6%	180
	11th to 20th	Day	19% 15% 35% 17% 9% 5%	180
	21st to end	Day	27% 8% 18% 38% 7% 2	198
January	1st to 10th	Night	34% 11% 21% 22% 10% 2	909
	11th to 20th	Night	27% 8% 22% 28% 13% 1	760
	21st to end	Night	24% 8% 24% 29% 13% 2	836
February	1st to 10th	Night	29% 9% 21% 28% 14% 1	760
	11th to 20th	Night	22% 9% 20% 33% 15% 1	744
	21st to end	Night	19% 9% 20% 31% 19% 3	628
March	1st to 10th	Night	23% 9% 22% 28% 17% 2	760
	11th to 20th	Night	19% 9% 25% 29% 17% 1	760
	21st to end	Night	17% 6% 27% 31% 16% 2	836
April	1st to 10th	Night	18% 11% 20% 31% 19% 2	760
	11th to 20th	Night	17% 8% 24% 36% 14% 1	705
	21st to end	Night	17% 8% 25% 37% 14%	428
May	1st to 10th	Night	12% 10% 21% 38% 20%	380
	11th to 20th	Night	12% 6% 20% 41% 20% 1	374
	21st to end	Night	18% 5% 19% 33% 24% 1	411
June	1st to 10th	Night	17% 9% 17% 41% 14% 1	380
	11th to 20th	Night	17% 7% 17% 38% 20% 1	380
	21st to end	Night	12% 5% 16% 39% 25% 3	380
July	1st to 10th	Night	11% 3 14% 37% 34% 1	370
	11th to 20th	Night	6% 4 18% 39% 31% 2	368
	21st to end	Night	8% 2 9% 42% 38% 1	416
August	1st to 10th	Night	6% 2 12% 33% 44% 3	378
	11th to 20th	Night	6% 1 10% 40% 39% 4	376
	21st to end	Night	9% 4 11% 43% 30% 2	765
September	1st to 10th	Night	11% 3 13% 39% 30% 4	760
	11th to 20th	Night	15% 5% 12% 29% 34% 6%	760
	21st to end	Night	19% 4 18% 36% 20% 3	760
October	1st to 10th	Night	16% 4 19% 34% 25% 3	760
	11th to 20th	Night	21% 7% 18% 32% 20% 2	760
	21st to end	Night	24% 7% 22% 31% 13% 3	836
November	1st to 10th	Night	32% 7% 21% 31% 8%	760
	11th to 20th	Night	29% 10% 23% 25% 11% 2	760
	21st to end	Night	29% 8% 21% 27% 12% 3	940
December	1st to 10th	Night	26% 8% 20% 32% 13% 2	950
	11th to 20th	Night	30% 8% 22% 30% 9% 1	963
	21st to end	Night	32% 7% 22% 29% 9% 1	1144

Page generated at 2024-11-02 23:11:13. Version ac07

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