Weather, by nature, is complex. Rules to simulate it no less so. A simple campaign may well do without such rules, but days and weeks of campaigning without a foggy morning or a soggy afternoon lacks luster.
A commander of a force consisting of mainly heavy foot avoids a soggy battlefield against a force with longbows. She rather favors dry ground and high winds. A fleet of troop transports rides out a storm at sea. The force it carries is delayed, the mission compromised. Swelling rivers cut off reinforcements. Without them, it is to be a muddy battle against an overwhelming force. These occasions lend verisimilitude to the wargames campaign.
This is the fifth of five articles, which discuss strategic movement in the Valormr Campaign.
The effects described here are general conditions applied to a period, but the conditions do not define the weather for every passing minute. Players are encouraged to embellish for dramatic effect. High winds toss treetops in gusts. A day of light rain is broken up by passing clouds and the occasional ray of sunshine. Hard rain is a steady pour, punctuated by momentary breaks. Fog drifts in banks across the terrain, clearing for an instant, in which the enemy is glimpsed, before another fog rolls in.
To determine daily and nightly weather, we adapt Chainmail’s weather rules (21-2) as follows.
Periods: As stated in the introduction, each 24-hour turn is divided into two periods, day and night.
Starting Weather: The morning of the campaign’s first day—when Anax Archontas raids the citadel—is clear.
Period Weather: Roll on the weather tables on subsequent mornings and evenings, that is, prior to diurnal and nocturnal movement. Thus, weather is determined for each period, twice per turn.
Changing Weather: On a Cloudy or Clears result, the condition takes effect without another dice roll. On a Rain result, roll again on the Rainy table to determine if the rain is light or hard or only threatens (on a Cloudy result).
Fog and Wind Dice
For any period that a weather change is indicated (shown as an arrow on the weather table), roll an additional dice. A result of 1 indicates fog, a 6 indicates a wind phenomenon.
Fog lasts for at least half the period. At the half, roll again: 1-2 the fog persists. In the case of a persistent fog, it continues the next period on a roll of 1-2, rolling for each half period. A persistent fog lifts on a roll of 3-6 or when the weather dice indicates another change.
If a wind phenomenon is indicated, roll another dice. A result of 1 indicates calm wind, a 5 high winds, and a 6 a gale for the half period. A gale effects sea and coast hexes. On land, a gale becomes high winds. Similar to fog, at the half and at each subsequent half period, the wind phenomenon continues on a roll of 1 or until the weather dice indicates another change.
The campaign opens in late autumn. After a few weeks, wintry conditions bring a halt to the campaigning season, which then picks up again in the spring. The campaign is expected to conclude before the next solstice. We ignore, therefore, the extreme weather effects, such as intense heat and cold and snowfall.
Some effects are cumulative. These begin at the end of the triggering period and continue in subsequent periods until the effect is cured by other weather.
Battlefield Weather: Using this system, we arrive at prevailing conditions throughout the days and nights. In addition to strategic movement, weather impacts the condition of a potential battlefield, once opposing forces make contact. In most cases, as in movement, weather effects are the same on the battlefield as on the strategic map. Where effects differ, they are noted.
Advanced: Tactical Weather
To strategic-level weather, we might add changing weather during a battle. The Chainmail system is intended for this purpose. The additional burden of another dice roll every other turn during battle, however, plus tracking cumulative effects, compared to the benefits in verisimilitude push battlefield weather into the bailiwick of an advanced game.
- One period of light rain maintains present conditions.
- Two consecutive periods of light rain equal one period of hard rain.
- During a period of hard rain, overland travel is reduced by 25%.
- One period of hard rain makes fords impassable.
- Two consecutive periods of hard rain renders ferries inoperable.
- Three consecutive periods reduce all movement by half.
- A fourth brings all movement to a halt.
Curing: Following one period of clear or two periods of cloudy, subsequent periods of clear and cloudy reduce the effects of rain in steps. For example, after three consecutive periods of hard rain, a second period of clear reduces the effects to the previous state, as if there had been two periods of hard rain. Two periods of cloudy equal one period of clear.
- Fog prevents seagoing vessels from entering or leaving port.
- Fog reduces the speed of ships at sea by 50% for each half-period it persists. Since a half-period represents one-quarter of a sailed ship’s move, divide its move points by eight, the result being its move points for the half-period.
- Fog does not effect overland strategic movement.
Battlefield: Fog limits visibility to a range of 30 to 180 yards (dice × 30). Any creatures sensitive to bright light suffer no adverse effects from the sun’s glow.
- Calm prevents any movement of sailed vessels. Galleys and longships must take to the oars.
- Calm wind has no impact on overland strategic movement.
- High winds prevent seagoing vessels from entering or leaving port.
- Sailed vessels at sea move 50% faster in each half-period the high winds persist.
- High winds have no impact on overland strategic movement.
Battlefield: High winds reduce missile-fire hits by one. Catapults are not effected.
- No movement is allowed in gale winds, as all ships at sea must lower sails, drop anchor, and ride out the storm.
- A vessel on a coast hex may beach.
Adapting Chainmail’s weather system, as we have done, leaves little chance for a drought. Using another system or summer season campaigning, though, drought effects should be considered.
After four consecutive weeks without at least four periods of rain, whether hard or light, the land is in a state of drought.
- In the fifth week without sufficient rain:
- Overland move points are reduced by 25%;
- Major rivers are treated as minor rivers;
- Minor rivers are fordable along their length.
- A sixth week of drought further reduces overland movement to half normal.
- A seventh week:
- Major rivers are fordable;
- Minor rivers are no longer navigable;
- Movement is reduced to only 25% normal;
- Forces lose 5% to 15% (half-dice × 5) per week as casualties.
- In the eighth week, loses due to casualties increase to 10% to 30% (dice × 5).
Curing: A drought is eased by one week with each period of light rain, where a hard rain is considered two periods of light rain. So, a light rain in the sixth week brings conditions back to as they were in the fifth week. If it were a hard rain, the fourth week, after which another light rain in the same week ends the drought.