---
key: practice/weather-window
type: practice
id: weather-window
lang: en
title: The weather window
summary: Make a random outcome part of a decision rather than just a surprise.
updatedAt: '2026-10-20'
status: active
url: 'https://gamemechanics.pro/en/knowledge/practice/weather-window/'
jsonUrl: 'https://gamemechanics.pro/api/v1/knowledge/en/practice/weather-window.json'
markdownUrl: 'https://gamemechanics.pro/content/knowledge/en/practice/weather-window.md'
aliases: []
tags:
  - Chance and balance
sourceIds:
  - source-3e6c21889ae768e0
  - source-6f794a271cd60b9c
sources:
  - id: source-3e6c21889ae768e0
    title: 'Challenges for Game Designers: author website'
    url: 'https://designgames.wordpress.com/'
    verifiedAt: null
  - id: source-6f794a271cd60b9c
    title: 'Challenges for Game Designers: table of contents'
    url: 'https://designgames.wordpress.com/toc/'
    verifiedAt: null
relations:
  - type: practices
    direction: incoming
    label: What this helps you learn
    key: lesson/controlled-randomness
    title: Randomness and unlucky streaks
    url: 'https://gamemechanics.pro/en/lessons/controlled-randomness/'
    jsonUrl: >-
      https://gamemechanics.pro/api/v1/knowledge/en/lesson/controlled-randomness.json
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      https://gamemechanics.pro/content/knowledge/en/lesson/controlled-randomness.md
  - type: practices
    direction: incoming
    label: What this helps you learn
    key: path/balance
    title: Balance and progression
    url: 'https://gamemechanics.pro/en/learn/balance/'
    jsonUrl: 'https://gamemechanics.pro/api/v1/knowledge/en/path/balance.json'
    markdownUrl: 'https://gamemechanics.pro/content/knowledge/en/path/balance.md'
  - type: uses
    direction: outgoing
    label: Sources in the selection
    key: resource/challenges-for-game-designers
    title: Challenges for Game Designers
    url: >-
      https://gamemechanics.pro/en/resources/#resource-challenges-for-game-designers
    jsonUrl: >-
      https://gamemechanics.pro/api/v1/knowledge/en/resource/challenges-for-game-designers.json
    markdownUrl: >-
      https://gamemechanics.pro/content/knowledge/en/resource/challenges-for-game-designers.md
placements:
  - title: In the original collection
    url: 'https://gamemechanics.pro/en/practice/#weather-window'
supersededBy: []
attributes:
  topic: chance
  level: intermediate
  minutes: 50
endsAt: null
provenance: >-
  Thematic inspiration: Challenges for Game Designers by Brenda Brathwaite and
  Ian Schreiber. These scenarios, constraints and checks are independently
  written around broad game-design learning topics. This is not a translation or
  a sequential retelling of the book exercises.
license: CC-BY-4.0
codeLicense: MIT
attribution: gamemechanics.pro contributors
---
# The weather window

id: weather-window
type: practice
key: practice/weather-window
lang: en
status: active
url: https://gamemechanics.pro/en/knowledge/practice/weather-window/

Make a random outcome part of a decision rather than just a surprise.

## Goal

Make a random outcome part of a decision rather than just a surprise.

## Scenario and materials

An expedition must send fragile cargo today or wait for another weather window. Today's forecast gives known probabilities for three outcomes. Design the cost of waiting, rewards and losses, then compare the choices of a cautious player and a risk-taking player.

Event cards

## Constraints

- Probabilities, rewards and losses are visible to the player.
- A ten-card deck can represent the outcomes.
- Waiting has a cost; it does not grant a free retry.

## Steps

1. Build a deck with the intended proportions of outcomes.
2. Calculate the expected result of sending: sum each outcome's result multiplied by its probability.
3. Compare sending and waiting at two resource levels. Play through a few outcomes and note separately that this small sample does not establish balance.

## Deliverable

The deck, a table of probabilities and consequences, an expected-result calculation and two example decisions.

## Check your work

- The probabilities sum to one.
- The player knows what they can gain and lose.
- Expected gain and the risk of losing the last resources are considered separately.

## Reflect

Why might a player choose the option with a lower expected reward?

## Connected materials

- What this helps you learn: [Randomness and unlucky streaks](https://gamemechanics.pro/en/lessons/controlled-randomness/) (key: lesson/controlled-randomness)
- What this helps you learn: [Balance and progression](https://gamemechanics.pro/en/learn/balance/) (key: path/balance)
- Sources in the selection: [Challenges for Game Designers](https://gamemechanics.pro/en/resources/#resource-challenges-for-game-designers) (key: resource/challenges-for-game-designers)

## Sources and provenance

Thematic inspiration: Challenges for Game Designers by Brenda Brathwaite and Ian Schreiber. These scenarios, constraints and checks are independently written around broad game-design learning topics. This is not a translation or a sequential retelling of the book exercises.

- [Challenges for Game Designers: author website](https://designgames.wordpress.com/) (id: source-3e6c21889ae768e0)
- [Challenges for Game Designers: table of contents](https://designgames.wordpress.com/toc/) (id: source-6f794a271cd60b9c)

CC-BY-4.0 · gamemechanics.pro contributors